Dan Margulis Applied Color Theory
Adobe RGB v. sRGB
Date: Thu, 19 Feb 2004 01:13:37 -0000
From: “Victoria Bampton”
Subject: AdobeRGB vs sRGB
Hi all!
I’m sorry - I’m sure this is a question
that’s been asked many times, but I’ve trawled back through the
archives, and I can’t find what I’m looking for.
I’ve been lurking on the list for a long time, and I’m
sure that you’re the best people to help me, so thanks in advance...
We have a professional portrait/wedding photographic
studio, and are in the process of changing to digital. The camera
we’ve gone for is a Canon 10d. Our labs print to wet-process
photographic paper, and ask for AdobeRGB files. As far as I
understood, we are therefore best setting the camera to AdobeRGB, and
keeping that colour space right the way through the workflow. But we were
told today by another professional that we should be using sRGB and then
converting to AdobeRGB. Which is best, please???
Sorry for such a basic question! Many thanks
for your help.
Regards
Victoria
___________________________________________________________________________
Date: Wed, 18 Feb 2004 20:30:59 -0800
From:Paul D. DeRocco
Subject: RE: AdobeRGB vs sRGB
First of all, I don’t understand why any
professional lab should be unable to handle _any_ color space, as long as
there’s an embedded profile. You’d think the expensive
equipment they use would be able to keep up with the lowly stuff that we
mere mortals use, like Photoshop, Epson printers, and so on.
But the answer to that question is that you might as
well shoot Adobe RGB. There’s no point in shooting sRGB, which
doesn’t allow quite such saturated greens (and cyans and yellows),
and then converting to Adobe RGB.
However, if you shoot JPEGs in the camera, and use
the Adobe RGB setting on the camera, be aware that it does not actually
embed an Adobe RGB profile in each image. To make sure that the lab gets it
right, you really should embed the profile. You can either run the JPEG
through a photo editor like Photoshop, and tell it to embed the proper
profile, or (better) you can shoot in raw mode and tell the conversion
software you want Adobe RGB, in which case it will do the proper embedding.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Wed, 18 Feb 2004 22:36:33 -0800
From: J Walton
Subject: RE: AdobeRGB vs sRGB
You may as well leave it in Adobe RGB if you have to
deliver that. I’m not sure what the advantage of sRGB would be
if you are delivering RGB files.
___________________________________________________________________________
Date: Thu, 19 Feb 2004 07:27:27 -0500
From: Laurentiu Todie
Subject: Re: AdobeRGB vs sRGB
The lab should have a profile for each machine they
use for printing. If you have a calibrated monitor, you should convert to
that color space (after retouching and saving a version in AdobeRGB) to see
what the picture will look like printed.
Laurentiu
___________________________________________________________________________
Date: Thu, 19 Feb 2004 07:45:09 -0500
From: “Annette Murray”
Subject: RE: AdobeRGB vs sRGB
The lab should have a profile for each machine they use
for printing.
If you have a calibrated monitor, you should convert to
that color space
(after retouching and saving a version in AdobeRGB) to
see what the picture
will look like printed.
Convert or Assign??
Annette Murray
Prepress and Color Consultant
ANRO Inc.
222 Lancaster Ave.
Devon, PA 19333
Website: ANRO.com
800.355.2676 x241
___________________________________________________________________________
Date: Thu, 19 Feb 2004 09:12:15 -0500
From: Jim Rich
Subject: Re: AdobeRGB vs sRGB
Laurentiu,
I am not sure I understand your comment.
Are you saying to use the monitor profile for a
conversion?
Or are you saying that each computer will have a
monitor profile that controls the monitors hardware. And that during the
process of capturing an image you will assign a scanner profile and
then convert to an Adobe working space then do your retouching. And
all the while in that process the monitor will maintain a consistent
view of the color because the monitor is using monitor profile that
controls the monitor.
Or are you saying something else?
Jim Rich
___________________________________________________________________________
Date: Thu, 19 Feb 2004 12:08:47 -0400
From: “Ellie Kennard”
Subject: RE: AdobeRGB vs sRGB
Neither convert nor assign, but use soft proof (View
- Proof and then use the supplied profile for soft proofing).
If you open a duplicate without soft-proofing, you
can then compare to make your colour corrections.
Ellie
—
Ellie Kennard
Innovative Imaging Studio
http://www.iiStudio.com
_____________________________________________________________________________
Date: Thu, 19 Feb 2004 14:25:34 -0500
From: Laurentiu Todie
Subject: Re: AdobeRGB vs sRGB
Your camera assigned the AdobeRGB space to the shot;
you convert for printing only.
___________________________________________________________________________
Date: Thu, 19 Feb 2004 14:40:29 -0500
From: Laurentiu Todie
Subject: Re: AdobeRGB vs sRGB
Jim, The best use of a monitor profile for humans is
to assign to... screen shots : )
Laurentiu
___________________________________________________________________________
Date: Thu, 19 Feb 2004 12:09:05 -0800
From: “Michael Plack”
Subject: Re: AdobeRGB vs sRGB
Victoria,
AdobeRGB is a larger colorspace than sRGB.
Therefore, it stands to reason that if you were to convert from the
larger to the smaller space, no colors would be lost. However, if you
were to convert from the smaller to the larger colorspace, interpolation
would be required resulting in a loss of color fidelity. Therefore,
for your situation, shooting in AdobeRGB would be the way to go (unless you
chose to shoot in RAW mode).
BTW, you mentioned that you were told by
another professional that shooting in sRGB and converting to AdobeRGB would
be the appropriate workflow. Was this ‘professional’
another photographer, or perhaps, hopefully, your accountant?
Michael Plack
___________________________________________________________________________
Date: Thu, 19 Feb 2004 22:15:04 -0000
From: Victoria Bampton
Subject: RE: AdobeRGB vs sRGB
Thanks for all the replies everyone.
You’ve confirmed exactly what I’d
previously understood from this list... but now I have the evidence from
you to show my father that he was told the wrong info. What worries
me more, is that this ‘professional’ runs Digital Photography
and Photoshop for Pro Photographers courses in the UK, is very well known,
but has some very off-the-wall ideas on colour management. Having said
that, my father is very new to digital, and therefore possibly may have
misunderstood. But either way, thanks for the info. This is a
great list!
Victoria Bampton
___________________________________________________________________________
Date: Fri, 20 Feb 2004 12:45:47 -0500
From: Dan Margulis
Subject: RE: AdobeRGB vs sRGB
Michael Plack writes,
AdobeRGB is a larger colorspace than sRGB.
Therefore, it stands to reason
that if you were to convert from the larger to the
smaller space, no colors
would be lost.
Precisely the opposite is true. The larger colorspace
can define colors that the smaller one can’t touch. This is always
the problem area in conversions, because no algorithm can make a correct
decision every time on how to handle out-of-gamut colors. It is always
easier to go from smaller to larger. This is particularly so in the present
case where Victoria is presumably (because her work doesn’t seem to
feature particularly brilliant colors) not attempting to access colors that
exist in Adobe RGB but not in sRGB.
However, if you were to convert from the smaller to the
larger colorspace, interpolation would be required
resulting in a loss of
color fidelity.
The larger colorspace can’t support all of the
subtle transitions of the smaller one, true. But even if this were a
real-world problem (which it isn’t) it would be inherent in the
definition of Adobe RGB, not having anything to do with the conversion
process.
As for “interpolation”, this in principle
might happen going from the larger to the smaller space, but in practice it
again isn’t a problem. The files are being cross-referenced to LAB,
which, as part of the process,is generating valid intermediate data, not
random interpolations.
I’ve run lots of multiple sRGB>Adobe
RGB>sRGB conversions. It isn’t quite as lossless as
sRGB>LAB>sRGB, but there’s no realistic danger in doing it.
Adobe RGB>sRGB>Adobe RGB can be quite risky.
I don’t see that there’s any reason in
Victoria’s case to do anything other than the obvious, which is to
capture the image in whichever RGB seems to capture it best, and then
convert it later or not as the case may be.
Dan Margulis
___________________________________________________________________________
Date: Fri, 20 Feb 2004 10:29:57 -0800
From:Paul D. DeRocco
Subject: RE: AdobeRGB vs sRGB
From: Dan Margulis
I’ve run lots of multiple sRGB>Adobe
RGB>sRGB conversions. It
isn’t quite as lossless as sRGB>LAB>sRGB,
but there’s no
realistic danger in doing it.
Actually, if you use the Perceptual rendering intent,
that will desaturate your greens a bit, because the second conversion
compresses the gamut a bit in order to make room for all those nonexistent
colors that are out of gamut for sRGB.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Fri, 20 Feb 2004 20:29:37 -0000
From: Victoria Bampton
Subject: RE: AdobeRGB vs sRGB
Hi Dan
Thanks for your input. So am correct in
thinking, therefore, that as our lab want AdobeRGB files, and our working
space is always AdobeRGB, that is would make the most sense to capture in
AdobeRGB too? We never use sRGB for anything, so there isn’t
any benefit to capturing in sRGB is there? Are we not better to avoid
converting at all if possible?
Thanks for the clarification.
Victoria
___________________________________________________________________________
Date: Sat, 21 Feb 2004 00:35:56 -0000
From: “Robert Catto”
Subject: Re: AdobeRGB vs sRGB
Hi Victoria, sorry to throw a cat among the pigeons
on this one;
Perhaps the reason you were told to shoot in sRGB
& convert was due to an article on the web, which I’ve read (but
can’t locate just at the moment), where Chuck Westfall of Canon USA
recommended exactly that.
It was specifically relating to the 10D, and
essentially stated that while the colour space is indeed larger, the camera
is perhaps ‘better’ at rendering in sRGB? I can’t
give you a better description than that at the moment, I’m afraid,
but I definitely remember coming away with that impression.
I’m guessing it was on Rob Galbraith’s
forum (http://www.robgalbraith.com) as Chuck often writes there; and
I’m sure I’ll find it as soon as I hit send on this message!
R
___________________________________________________________________________
Date: Sat, 21 Feb 2004 21:13:01 -0000
From: “dmargulisnj”
Subject: Re: Adobe RGB vs. sRGB
Victoria writes,
Hi Dan
Thanks for your input. So am correct in thinking,
therefore, that as
our lab want AdobeRGB files, and our working space is
always
AdobeRGB, that is would make the most sense to capture
in
AdobeRGB too? We never use sRGB for anything, so there
isn’t
any benefit to capturing in sRGB is there? Are we not
better to
avoid converting at all if possible?
I wouldn’t worry about the conversion. It was
suggested elsewhere (I don’t know this myself) that the particular
camera produces a better quality capture in sRGB than in Adobe RGB. You can
certainly experiment to find out whether this is so.
I’d recommend staying away from Adobe RGB in
any of the following cases:
1) Your work commonly showcases brilliant colors;
2) CMYK is your principal destination;
3) Your RGB files are likely to be handled by
strangers.
It seems that none of these factors apply in your
case, so if you’re satisfied that the capture quality in Adobe RGB
is good, then your logic is correct, and you should go Adobe RGB all
the way.
Dan Margulis
___________________________________________________________________________
Date: Sat, 21 Feb 2004 19:00:42 -0500
From:Russell Proulx
Subject: Re: AdobeRGB vs sRGB
Victoria,
I find that using a larger colour space such as
AdobeRGB allows one to adapt their files to a wider variety of output
mediums. Some output methods may offer access to colours that would no
longer exist once a file is converted to sRGB. Why not capture as wide a
colour gamut at the shooting stage. Some even recommend scanning in wide
gamut colourspaces such as ProPhotoRGB and saving this as a sort of
‘master’ for the day that a wide gamut colour printer comes
around.
I find it interesting that your lab requests only
AdobeRGB files. Most digital-to-photopaper printers (Noritzu, Pictrography,
Frontier, etc..) are manufactured to reproduce the sRGB colourspace which
represents what 99.9% of consumer digital cameras use, and the consumer
market is what drives the industry.
If your lab wants AdobeRGB then give them AdobeRGB.
The problem I’ve seen here in Montreal is that the workflow of too
many consumer labs is to ignore the embedded colourspace of the original
and simply output it as if the it was in sRGB (the consumer standard). Even
some pro labs have been slow to grasp that RGB comes in different flavours
and they need to convert from the clients colourspace to whatever their
printer expects (or better still convert to the printer profile). The
safest thing to do here is to convert to sRGB before sending the file to a
lab so, even if they don’t check, it’ll at least be in the same
colourspace of 99% of their clients and will print just fine. I have to
wonder how your local pro lab is dealing with the fact that most digital
cameras (except high-end models) can ONLY shoot in sRGB? Are they turning
these clients away? (I think not).
I suspect that your lab ‘thinks’
they’re getting more colours out of their equipment by recommending
AdobeRGB from clients who have the option. But they must certainly also
accept sRGB. I’m convinced the lab is making a recommendation only
and would deal with whatever flavour of RGB an image is in and output it
accordingly.
Hope this helps shine some light on the subject :-)
Russell Proulx
Montreal, Canada
___________________________________________________________________________
Date: Sat, 21 Feb 2004 21:17:14 -0500
From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB
From: “dmargulisnj” <
I’d recommend staying away from Adobe RGB in any
of the
following cases:
1) Your work commonly showcases brilliant colors;
2) CMYK is your principal destination;
3) Your RGB files are likely to be handled by
strangers.
Dan,
Is your reasoning for number 1 that the profile might
be ignored by someone further down the line? By my understanding, brilliant
colors will be more easily contained and handled by the larger AdobeRGB
space rather than sRGB.
john castronovo
___________________________________________________________________________
Date: Sun, 22 Feb 2004 10:16:51 -0600
From: “Ronal Walraven”
Subject: Subject: Re: Adobe RGB vs. sRGB / Assign vs
Convert
As a side question. Do digital cameras convert the
image capture to sRGB or Adobe RGB color space (remapping out of gamut
pixels) or just assign the color space to the image (not remapping any
pixels)? This question is not for a specific camera model but for digital
cameras in general or is the answer camera model specific?
Ronal’ Photography & Digital Imaging
___________________________________________________________________________
Date: Sun, 22 Feb 2004 09:09:22 -0800
From: David Cardinal
Subject: Re: Adobe RGB vs. sRGB / Assign vs Convert
As a side question. Do digital cameras convert the
image
capture to sRGB or Adobe RGB color space (remapping out
of
gamut pixels) or just assign the color space to the
image
(not remapping any pixels)? This question is not for a
specific camera model but for digital cameras in
general or
is the answer camera model specific?
The answer is camera specific. Generally there are
(at least) 4 scenarios:
* Cameras which both convert the image to a
colorspace & correctly add the ICC profile to the image. The Nikon D2H,
and the post-firmware-updated D1X and D1H are examples.
* Cameras which convert the image to a colorspace but
don’t tag the image. Pre-firmware updated Nikon D1X and D1H are
examples of this, along with (as I recall) the Canon 1D.
* Cameras which shoot in sRGB but don’t add it
as a profile tag. Many consumer cameras fall into this category. Photoshop
will still often open these images as being from sRGB based on some default
behaviors for an EXIF “colorspace” flag, which is not the same
thing as a real profile being embedded.
* Cameras which don’t shoot in any particular
colorspace. The original D1 is an example (it turns out to have been
factory calibrated on NTSC monitors, so that was a close approximation, but
Nikon never mentioned that until many of us wrote about it as a
“tip”), as are most consumer cameras over a year or two old.
The big caveat is of course how well the cameras do
the conversion. High-end models have gotten quite good at it. I suspect
many consumer cameras that purport to shoot into sRGB aren’t as
close. Even the pro models benefit from a custom profile, as of course the
conversion logic is model specific but not specific to your particular
camera.
—David
___________________________________________________________________________
Date: Sun, 22 Feb 2004 09:55:19 -0800
From:Paul D. DeRocco
Subject: Re: Adobe RGB vs. sRGB / Assign vs Convert
I’ve never found the color from any digicam,
including my 10D, to be so accurate that one could even reasonably say
whether an image supposedly in a particular color space was actually in
that color space, in any meaningful sense. I always always always have to
play with the color, not to mention every other tweak under the sun, to
turn the raw material into a nice-looking finished product.
So unless you’re using the camera to provide
evidence of what precise color something was for a court case, I
wouldn’t worry a whole heck of a lot about it. Just eyeball it
afterwards.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Sun, 22 Feb 2004 14:28:39 -0500
From:Russell Proulx
Subject: Re: Subject: Re: Adobe RGB vs. sRGB / Assign
vs Convert
On 22 Feb 2004 at 10:16, Ronal Walraven wrote:
As a side question. Do digital cameras convert the
image capture to sRGB or
Adobe RGB color space (remapping out of gamut pixels)
or just assign the
color space to the image (not remapping any pixels)?
This question is not
for a specific camera model but for digital cameras in
general or is the
answer camera model specific?
The RAW capture of the CCD or CMOS camera sensor is
converted to sRGB or AdobeRGB colourspace. If you can save your image in a
RAW format then, with the right software, you can convert it to other
colourspaces as well. ie: The Adobe PhotoshopCS RAW convertor offers output
to your choice of AdobeRGB, ColormatchRGB, sRGB and ProPhotoRGB and the RGB
pixel values are adjusted accordingly.
Russell
___________________________________________________________________________
Date: Sun, 22 Feb 2004 17:03:41 EST
From: Dan Margulis
Subject: Re: Re: Adobe RGB vs. sRGB
John Castronovo writes,
Is your reasoning for number 1 that the profile might
be ignored by someone
further down the line?
No.
By my understanding, brilliant colors will be more
easily contained and
handled by the larger AdobeRGB space rather than sRGB.
The problem is that unless considerable care is taken
the brilliant colors are likely to be out of the gamut of whatever the
output device is. There are crutches (like a perceptual rendering intent)
but basically in such situations the choices are to become an expert color
corrector to restore what’s been lost when the file is converted, or
to accept second-quality color.
Dan Margulis
___________________________________________________________________________
Date: Sun, 22 Feb 2004 22:33:43 -0500
From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB
So then it’s your advice to the novice to stick
with sRGB whether the subject has a wide gamut or not? It certainly is
safer all around, but some colors will suffer. Possibly the trade off is
worth it.
john castronovo
___________________________________________________________________________
Date: Sun, 22 Feb 2004 21:00:25 -0800
From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB
From: john c.
So then it’s your advice to the novice to stick
with sRGB whether the
subject has a wide gamut or not? It certainly is safer
all
around, but some
colors will suffer. Possibly the trade off is worth it.
That’s up to you, but remember that the colors
you lose are so saturated that you can’t even see them on typical
monitors. And most printers that can reach them at all can only do so in
the midtones. It’s only green, and by extension yellow and cyan, that
are affected, since Adobe RGB and sRGB have the same red and blue
primaries.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Sun, 22 Feb 2004 23:05:43 -0800
From: Stephen Ray
Subject: Re: Re: Adobe RGB vs. sRGB
I’ve asked this question here before and I know
Dan has already answered:
What in our natural world contains colors outside of
the sRGB color space?
If there are PRACTICALLY no colors outside that
space, why open a can of worms by working in a space that’s contains
an even wider gamut?
I’ve seen demonstrations where Adobe98 was used
and resulted in a more brilliantly colored Epson print over the sRGB
version. All these demonstrations were of photographs. Bright, but solitary
in their use. My experience tells me that one with such prints would have a
difficult or impossible time reproducing that color on typical presses or
photo devices if they were required, and that’s often the case.
I find designers and photographers who are using
Adobe98 are far more disappointed when they see output from service bureaus
that those using sRGB. Usually the first thing they learn is the bureau has
no device to image that gamut. If they can possibly soft-proof,
they’re shocked at the gamut reduction and begin making phone calls
asking if what they see is correct.
The best Epson prints I’ve seen were color
managed to mimic a 3M Match Print which is a very small gamut compared to
Adobe98 or sRGB. The inkjet matched actual 3M, the original photo
transparency, some Pantone samples, stocastic press work, Xerox, and Lambda
display all in their exhibit booth. A PRACTICAL use of color gamut.
I find sRGB more practical than Adobe98 and I still
have huge issues recommending it!
-Stephen Ray
___________________________________________________________________________
Date: Mon, 23 Feb 2004 08:46:27 -0500
From: Terry Wyse
Subject: Re: Re: Adobe RGB vs. sRGB
On Feb 23, 2004, at 12:00 AM, Paul D. DeRocco wrote:
It’s only green, and by
extension yellow and cyan, that are affected, since
Adobe RGB and sRGB
have the same red and blue primaries.
Humm...really? Try taking an image of
people/fleshtones that’s in sRGB and then ASSIGN AdobeRGB to that
same image. The fleshtones will be bleeding red and oversaturated. Since
the red/blue primaries are the same and the gamma is identical, then what
is going on?
Terry
_____________________________
WyseConsul
Color Management Consulting
704.843.0858
___________________________________________________________________________
Date: Mon, 23 Feb 2004 06:25:02 -0800
From: “Michael Stokes”
Subject: RE: Re: Adobe RGB vs. sRGB
For color gamut, rain forest foliage (the really nice
blue/green Spring leaves, not late Fall yellowing ones), red/orange
Japanese maple leaves, human blood. If you consider textiles
“natural” then most dark saturated velvets...and many more.
For dynamic range, technically the sRGB standard
targets 80-100 cd/m^2 (typical CRT) and thus leaves out a lot of high
dynamic range imagery.
The family of P22 phosphor set which HDTV is based on
which in turn sRGB is directly derived is limited to what it is capable of.
Michael Stokes, Microsoft Corporation
___________________________________________________________________________
Date: Mon, 23 Feb 2004 07:26:43 -0700
From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB
on 2/23/04 12:05 AM, CitizenRay wrote:
What in our natural world contains colors outside of
the sRGB color space?
Natural world as seen by what? Humans? Look at sRGB
on top of a plot of CIE:LAB and you1ll see how tiny a color space it is
compared to what we can see.
Now plot sRGB on top of even CMYK Ink on paper and
it1s not fully contained. Take a 7 color ink jet and there are all kinds of
colors outside of sRGB.
Do you want to capture and use those colors? If so,
you do NOT want sRGB. If you don1t care, it1s fine and dandy.
Andrew Rodney
http://www.digitaldog.net
___________________________________________________________________________
Date: Mon, 23 Feb 2004 10:28:18 -0500
From:Russell Proulx
Subject: RE: Re: Adobe RGB vs. sRGB
On 22 Feb 2004 at 21:00, Paul D. DeRocco wrote:
the colors you lose are so saturated
that you can’t even see them on typical monitors.
I teach a Photoshop Class at a local college and can
easily demonstrate loss. Create a rainbow in in AdobeRGB and then convert
to sRGB (not the other way around) and even cheap monitors will show a
loss.
On 23 Feb 2004 at 8:46, Terry Wyse wrote:
Try taking an image of people/fleshtones that’s
in sRGB and
then ASSIGN AdobeRGB to that same image.
That’s a incorrect use of colour management.
You need to CONVERT the image from one space to another. Otherwise the RGB
numbers result in nonsense on the screen which is what you’re seeing.
All you’re proving is that RGB numbers for the same colour are
different in different colour spaces. When converted the numbers are
remapped to their closest equivalent and the difference from sRGB to
AdobeRGB will be ‘no difference at all’.
On 22 Feb 2004 at 23:05, CitizenRay wrote:
I’ve seen demonstrations where Adobe98 was used
and resulted in a more
brilliantly coloured Epson print over the sRGB version.
All these
demonstrations were of photographs. Bright, but
solitary in their use.
My experience tells me that one with such prints would
have a difficult
or impossible time reproducing that color on typical
presses or photo
devices if they were required, and that’s often
the case.
Almost every RGB image gets hurt somewhat when
converting to SWOP CMYK, especially the blues. You already know this. I
don’t feel better off by having a ‘dumbed down’ RGB so I
lose even less in the conversion to CMYK. Why not just scan in CMYK and
avoid all those needless colours altogether? You said it yourself
“resulted in a more brilliantly coloured Epson print over the sRGB
version. All these demonstrations were of photographs.” Most
photographers are replacing film with digital and want to keep as many
colours as they had before. Many photographers have always been
disappointed with how some of their images die on the press. That’s
the reality of that limited gamut. But there are many output options with
larger gamuts than a press and photographers need to make best use of these
print options as well. This includes multi-ink inkjet printers and
traditional silver photo prints which both offer better colour than CMYK.
And their gamuts will only get larger due to competition.
Photographer’s need to use a compromise
colourspace that makes the best use of diverse output technologies. Some
find that AdobeRGB works best for them or even larger colourspaces
(ProPhotoRGB). My advice to photographers is to learn to do their own CMYK
conversions (take Dan’s class, read his books!) and thus be much more
accurately aware of what’will be lost and how to deal with it. I
don’t see how someone working in sRGB will be any less disappointed
if they expect to reproduce exactly what they see on their screens on a
press.
Russell Proulx
Montreal
___________________________________________________________________________
Date: Mon, 23 Feb 2004 09:47:56 -0800
From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB
From: Terry Wyse
Humm...really? Try taking an image of people/fleshtones
that’s in sRGB
and then ASSIGN AdobeRGB to that same image. The
fleshtones will be
bleeding red and oversaturated. Since the red/blue
primaries are the
same and the gamma is identical, then what is going on?
Actually, the gamut is larger in the red direction,
but only in the 3D space where luminance is included. Adobe RGB and sRGB
have the same xy values for red, but Adobe has a higher Y value, which
means you can represent brighter reds, not more saturated ones. When I
compare this to various printer profiles, the extra red area doesn’t
overlap with any of them. For instance, the Epson 2200 on glossy paper
exceeds Adobe RGB in the brighter yellows, midtone magentas, and darker
cyans, but can’t do particularly bright reds.
Also, by the way, the gamma isn’t identical.
Adobe RGB is a true 2.2 curve, while sRGB is about 2.3 or 2.4 with a linear
segment at the bottom.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Mon, 23 Feb 2004 09:14:49 -0800
From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB
From: CitizenRay
What in our natural world contains colors outside of
the sRGB color space?
Various paints and cloth dyes are very saturated, and
I think even occasionally some flower colors. Not a whole heck of a lot,
though, and in reality desaturating these colors doesn’t necessarily
destroy the aesthetic effect of the image.
I find designers and photographers who are using
Adobe98 are far more
disappointed when they see output from service bureaus
that those using
sRGB. Usually the first thing they learn is the bureau
has no device to
image that gamut. If they can possibly
soft-proof, they’re shocked at the
gamut reduction and begin making phone calls asking if
what they see is
correct.
It’s certainly pointless to increase the size
of your editing gamut beyond what your monitor can do, if your printer
can’t do it. Since I make inkjet prints, I often use Adobe RGB.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Mon, 23 Feb 2004 10:46:56 -0800
From: Steven Barton
Subject: Re: Re: Adobe RGB vs. sRGB
From: “Russell Proulx”
My advice to photographers is to
learn to do their own CMYK conversions (take
Dan’s class, read his books!)
and thus be much more accurately aware of
what’will be lost and how to deal
with it. I don’t see how someone working in sRGB
will be any less
disappointed if they expect to reproduce exactly what
they see on their
screens on a press.
Converting images to CMYK well can be quite an art.
It certainly requires an investment in time and learning. Can the
photographer charge extra for this additional service and higher level of
control?
Steven Barton
Imaging Sciences & Partners
___________________________________________________________________________
Date: Mon, 23 Feb 2004 13:50:29 -0500
From: Terry Wyse
Subject: Re: Re: Adobe RGB vs. sRGB
On Feb 23, 2004, at 10:28 AM, Russell Proulx wrote:
That’s a incorrect use of colour management. You
need to CONVERT the image
from one space to another. Otherwise the RGB numbers
result in nonsense on
the screen which is what you’re seeing. All
you’re proving is that RGB
numbers for the same colour are different in different
colour spaces. When
converted the numbers are remapped to their closest
equivalent and the
difference from sRGB to AdobeRGB will be ‘no
difference at all’.
Of course it’s a “wrong”
application of color management but in the context of what I was responding
to, it was a valid statement. The original statement was something to the
effect of “the only difference between sRGB and AdobeRGB is the green
extension since the red/blue chromaticities are identical”. I was
only trying to demonstrate that there’s more going on than simply
having a different green coordinate. Not that I can tell you WHY exactly
that is the case, only that the difference between the two profiles goes
beyond simple chromaticities and gamma.
Terry
_____________________________
WyseConsul
Color Management Consulting
704.843.0858
___________________________________________________________________________
Date: Mon, 23 Feb 2004 11:30:37 -0800
From: Stephen Ray
Subject: Re: Re: Adobe RGB vs. sRGB
From: “Michael Stokes”
For color gamut, rain forest foliage (the really nice
blue/green Spring
leaves, not late Fall yellowing ones), red/orange
Japanese maple leaves,
human blood. If you consider textiles
“natural” then most dark saturated
velvets...and many more.<<
Do you actually have, or know of, LAB values for
these and where they fall regarding the sRGB space? Granted, anyone would
be hard pressed to measure velvet, blood, or exotic foliage.
For dynamic range, technically the sRGB standard
targets 80-100 cd/m^2
(typical CRT) and thus leaves out a lot of high dynamic
range imagery.
Is gamut not the same as dynamic range?
I’m afraid I bear a trait from my mother who
was from Missouri, the Show Me state.
-Stephen Ray
___________________________________________________________________________
Date: Mon, 23 Feb 2004 12:03:56 -0800
From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB
From: Russell Proulx
I teach a Photoshop Class at a local college and can
easily demonstrate
loss. Create a rainbow in in AdobeRGB and then convert
to sRGB (not the
other way around) and even cheap monitors will show a
loss.
It’s certainly true that some monitors can
display colors outside sRGB, but most not by much. (My LCD, not at all.) My
guess is that you’re doing the conversion in either Perceptual or
Relative Colorimetric mode. If the former, the color management engine will
desaturate even some of those Adobe RGB colors that theoretically fit
within sRGB, just to make room for the extended colors that don’t
fit. It does this even if those colors don’t actually exist in the
image. This is, I believe, a nonlinear desaturation, not as brutal as
merely assigning sRGB, but it does affect in-gamut colors.
If you try it in Relative Colorimetric mode, there is
still a white point change between the two color spaces, which means that
some colors still need to be pushed around to adapt to the different white
space. I wonder if you see the same degradation in Absolute Colorimetric
mode.
An odd quirk that most people may have not noticed is
that if you create an image with saturated greens in sRGB, and then convert
it to Adobe RGB, the greens will get slightly duller. Counterintuitive?
That’s because you’re actually seeing not the real colors but
the colors after converting to the monitor color space. If you’ve
selected the Perceptual rendering intent, it thinks it has to squeeze the
color space more when you display an Adobe RGB image than when you display
an sRGB image, even though your Adobe RGB was just converted from sRGB and
doesn’t have any of those super-saturated colors.
I suppose this happens with printers as well. Try to
use a color space that isn’t hugely out-of-range for the printer, or
stay away from Perceptual mode, or better yet, soft proof if you’re
lucky enough to have printer profiles that do that well.
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Mon, 23 Feb 2004 15:20:03 -0500
From:Russell Proulx
Subject: Re: Re: Adobe RGB vs. sRGB
On 23 Feb 2004 at 10:46, Steven Barton wrote:
Converting images to CMYK well can be quite an art. It
certainly requires an
investment in time and learning. Can the photographer
charge extra for this
additional service and higher level of control?
I do, and it’s increased my bottom line. I can
give clients work that they can rely on and charge more than I previously
did for film and processing (which I had to pay to someone else). It also
insures that my images won’t suffer at the hands of too may graphic
artists who still don’t know what they’re doing with hi-rez
images. I also supply images in RGB for those who do know what
they’re doing.
Russell Proulx
Montreal
___________________________________________________________________________
Date: Mon, 23 Feb 2004 12:56:09 -0800
From: Stephen Ray
Subject: Re: Re: Adobe RGB vs. sRGB
Andrew Rodney wrote:
Natural world as seen by what? Humans? Look at sRGB on
top of a plot of
CIE:LAB and you1ll see how tiny a color space it is
compared to what we can
see. Now plot sRGB on top of even CMYK Ink on paper and
it1s not fully contained.
Take a 7 color ink jet and there are all kinds of
colors outside of sRGB.
Do you want to capture and use those colors? If so, you
do NOT want sRGB. If
you don1t care, it1s fine and dandy.<<
Andrew,
We all know we can SEE huge extremes of color but
only use a very small portion of the range with both our eyes and in print.
We can’t really differentiate millions of blended tones and inked
prints only really need thousands. (This reminds of working with Kai Krause
and portraying continuous tone with 256 dithered colors on Ektachrome just
to prove a point.)
My notion is much like that of an audio engineer. We
use compression to make the product palatable. The garage band burns a CD
with dynamics so extreme it will never pass RIAA specs to get to the air
waves. A photographer or designer uses Adobe98 across all their Adobe apps
and images a fabulous comp on their Epson only to find no vendor in their
hemisphere can match the color. Compression is virtuous at times.
Yes, capturing everything I can but I wouldn’t
start or stop at Adobe98 unless I had no choice. Using a work space is
another issue and for me, that’s not Adobe98.
Stephen Ray
___________________________________________________________________________
Date: Mon, 23 Feb 2004 14:24:42 -0700
From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB
on 2/23/04 1:03 PM, Paul D. DeRocco wrote:
It’s certainly true that some monitors can
display colors outside sRGB, but
most not by much.
I1ve actually got a display (from Mitsubishi) that
displays 98% of the Adobe RGB gamut! It1s a pre-production unit but the
point is, this is technically doable. Funneling color into a tiny
colorspace based upon the notion that all display and output devices are as
tiny as sRGB is really painting yourself into a big corner.
Andrew Rodney
http://www.digitaldog.net
___________________________________________________________________________
Date: Mon, 23 Feb 2004 14:04:19 -0800
From:Paul D. DeRocco
Subject: RE: Re: Adobe RGB vs. sRGB
From: Andrew Rodney
I1ve actually got a display (from Mitsubishi) that
displays 98% of the Adobe
RGB gamut! It1s a pre-production unit but the point is,
this is technically
doable. Funneling color into a tiny colorspace based
upon the notion that
all display and output devices are as tiny as sRGB is
really painting
yourself into a big corner.
Is this monitor something I ought to look into
buying, or is it going to be some expensive monster like the Barco?
Ciao,
Paul D. DeRocco
___________________________________________________________________________
Date: Mon, 23 Feb 2004 17:41:28 -0700
From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB
on 2/23/04 3:04 PM, Paul D. DeRocco wrote:
Is this monitor something I ought to look into buying,
or is it going to be
some expensive monster like the Barco?
Not released yet and it will be inexpensive!
Andrew Rodney
___________________________________________________________________________
Date: Mon, 23 Feb 2004 22:28:55 -0500
From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB
From: “Andrew Rodney”
Funneling color into a tiny colorspace based upon the
notion that
all display and output devices are as tiny as sRGB is
really painting
yourself into a big corner.
Don’t you mean a little corner?
I just wanted to jump in here to say that I
agree with you. We never had a problem working in DonRGB (for many years
now), and I don’t think that I would say that if we were working in
sRGB. If we all limited ourselves to that smallest of color spaces that was
common to ALL devices, there would be few surprises - quite safe, but
certainly not beautiful color.
john castronovo
___________________________________________________________________________
Date: Mon, 23 Feb 2004 23:08:37 EST
From: Dan Margulis
Subject: Re: Re: Adobe RGB vs. sRGB
John Castronovo writes,
So then it’s your advice to the novice to stick
with sRGB whether the
subject has a wide gamut or not? It certainly is safer
all around, but some
colors will suffer. Possibly the trade off is worth it.
For a total novice, it’s probably best to do
what the majority does. sRGB has clearly become the industry default over
the last couple of years. Anybody who doesn’t have a good grasp
of what RGB definitions are (and total novices probably don’t)
shouldn’t be messing with Adobe RGB.
For people who are not particularly skilled with
color, but are shrewd enough to avoid any possibility of other people
misinterpreting their files, Adobe RGB is a good choice. Although in theory
it shouldn’t matter, in practice the use of Adobe RGB will favor
relatively more colorful files, which are generally a good thing.
I think that Adobe RGB is not particularly suitable
for most intermediate users. One of the biggest issues that the
professional photographers who attend my classes come in with is loss of
detail in brightly colored areas. Usually, this is an Adobe RGB problem. I
just got back from an on-site where the images were digital captures of
flowers, and CMYK output was the only consideration. That type of scenario
screams out for something other than Adobe RGB.
Expert users know the advantages and disadvantages of
using Adobe RGB and are well positioned to decide whether it makes sense
given their own workflow. Expert users are also ready and willing to assign
an sRGB profile to an Adobe RGB image where necessary, or vice versa. In
this area, I agree with everything that Russell Proulx has been posting.
Dan Margulis
___________________________________________________________________________
Date: Tue, 24 Feb 2004 10:35:56 -0000
From: Victoria Bampton
Subject: RE: Re: Adobe RGB vs. sRGB
Hello all!
I seem to have opened a can of worms on this one!
Everyone has a different opinion, and all have good reasons for that
opinion. Are you trying to confuse me now??
Ok, so having spent the last 3 years following this
list closely, and studying Dan’s book in detail (Dan, how about doing
a course in the UK?), so I’ve managed to follow the debate fairly
well. I understand which colours are compressed/lost in sRGB vs
AdobeRGB, and the benefits of not capturing detail that can’t be
printed/shown on screen, but considering our lab want AdobeRGB and
we’ve used AdobeRGB as our working space for the last 4 years with no
problems, what would be the benefits of capturing in sRGB, only to later
convert and therefore have to interpolate info? I’d be really
interested to read that article that Robert mentioned by Chuck Westfall - I
couldn’t find it.
Dan, what makes you say that sRGB has become the
industry default? In the UK, I haven’t yet come across a pro
lab who don’t want AdobeRGB. Is this just a case of they
don’t yet understand, or are wet-process photograph machines able to
cover the larger gamut? I understand that they should be able to
print from any colour space, but there does appear to be a noticeable
difference when I’ve sent sRGB files. CMYK output isn’t
an issue for us, as everything we do is either screen based (converted to
sRGB) or printed on inkjet now and again. Mostly it’s
wet-process photographs.
Thanks for everyone’s expert input - this has
been very interesting - I’ve learnt a lot!
Regards
Victoria
___________________________________________________________________________
Date: Tue, 24 Feb 2004 07:52:51 -0700
From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB
on 2/24/04 3:35 AM, Victoria Bampton wrote:
I understand which colours
are compressed/lost in sRGB vs AdobeRGB, and the
benefits of not capturing
detail that can’t be printed/shown on screen, but
considering our lab want
AdobeRGB and we’ve used AdobeRGB as our working
space for the last 4 years
with no problems, what would be the benefits of
capturing in sRGB, only to
later convert and therefore have to interpolate info?
None! Debate ended. Any color working space can be
hosed if the user doesn1t understand how to handle the files. Dumbing down
the process isn1t the right answer IMHO.
Dan, what makes you say that sRGB has become the
industry default?
Dan usually has his ear on the 3industry2 and thus
can tell us what is or isn1t a default. If the definitional of a default is
one that1s not all that great that a lot of color clueless vendors are
using as an excuse for good color practices (mostly consumer products in
this case) then I guess it1s a default. Where I come from and based upon
the PROFESSIONAL users I work with, Adobe RGB 1998 is far more a 3default2.
That is, far more users that have a clue about color avoid sRGB expect for
web use or purely display output.
UK, I haven’t yet come across a pro lab who
don’t want AdobeRGB.
Then you guys are far more advanced then a lot of
labs over here. Many have no idea about working in a color managed
workflow, have un-calibrated displays and no output profiles for their
devices. So the 3easy answer2 for customers who really don1t understand the
process any more than the lab is to simply suggest files come in as sRGB.
It might as well be monitor RGB (the users monitor ala Photoshop 4 and
earlier).
Is this just a case of they don’t yet understand,
or are wet-process photograph
machines able to cover the larger gamut?
There1s a nasty myth that such device can1t exceed
sRGB (not true) or that no output devices can output a color space larger
than sRGB (again not true).
I understand that they should be
able to print from any colour space, but there does
appear to be a
noticeable difference when I’ve sent sRGB files.
CMYK output isn’t an issue
for us, as everything we do is either screen based
(converted to sRGB) or
printed on inkjet now and again. Mostly
it’s wet-process photographs.
Even SWOP v2 (TR001) is slightly larger than sRGB.
Andrew Rodney
http://www.digitaldog.net
___________________________________________________________________________
Date: Tue, 24 Feb 2004 23:08:03 -0500
From:Russell Proulx
Subject: Re: Re: Adobe RGB vs. sRGB
On 24 Feb 2004 at 7:52, Andrew Rodney wrote:
There1s a nasty myth that such device can’t
exceed sRGB (not true)
Andrew,
If it’s wrong then I really want to know what
it right. Except for the few books available, such as those from
Fraser/Murphy/Bunting book and Abhay Sharma, the main source of info on how
ICC color management works are email lists like this one and websites such
as
http://www.shootsmarter.com/infocenter/wc025.html
which offer up info on photo printers that appears to
be well founded.
If the info on this website is wrong then I do wonder
why don’t they know it? Where’s the motive to spread untruths?
I REALLY DO want colour management to work (at least
in my RGB workflow) and find it disturbing to read so many contradictions
and witness debates akin to Julia Child vs Jacques Pepin <g>
I’m sure I even read an old list posting
(colorsync list?) where someone (no kidding, I really thought it was YOU)
revealed that Fuji engineers specifically used the sRGB colourspace as
their target for the color gamut characteristics of the Pictro.
I’m not looking for an argument (seriously). I
only want to know what the right answer is. What I have noticed is that
sRGB files sent unconverted (ie: processor doen not check for embedded
profiles of incoming images) to Kodak/Noritzu minilab printers come out
looking VERY close to what I see on the screen. Files in other colourspaces
come out wrong.
Russell :-)
___________________________________________________________________________
Date: Wed, 25 Feb 2004 00:51:44 EST
From: Dan Margulis
Subject: Re: Re: Adobe RGB vs. sRGB
Victoria writes,
Dan, what makes you say that sRGB has become the
industry default? In the
UK, I haven’t yet come across a pro lab who
don’t want AdobeRGB.
Adobe RGB has always been most popular among
professional photographers. The question to which I was responding,
however, pertained to “novices” and to Photoshop users as a
whole. In that group, sRGB clearly has become the standard. In fact, posts
to this group indicate that most professional labs in this hemisphere are
looking for sRGB. Of course, this is all being driven by consumer-level
digital cameras and printers, almost all of which operate in sRGB. Also,
you’ve seen in this thread several suggestions from others that Adobe
RGB carries disadvantages. Such commentary would have been unusual even two
years ago.
A couple of months ago, in a significant milestone,
several prominent members of the group that I call the Conventional Color
Management Wisdom suggested that at this point, it is proper and desirable
to assume that an RGB file without an embedded profile is an sRGB file.
Previously, the CCMW had been that any untagged file is meaningless mystery
meat.
In making this suggestion, the CCMW by no means is
saying that sRGB is good, only that it has achieved a dominating position.
If you decide to use some other RGB definition, fine, but you have to
realize that you are living in an increasingly sRGB world, so the onus is
on you to make sure that your non-sRGB files will be handled properly by
others.
I don’t think novice users are capable of doing
that, so I recommend that they stick with sRGB. In fact, I think all users
should be looking at their workflow. There’s an advantage to working
in a standard space, even if isn’t the standard space you yourself
would want. If you look at your workflow and see a bigger
advantage in working in some other RGB (as Russell does) fine. But if you
can’t think of any reason to choose something different, I’d go
with the flow at this point.
In your case, there does seem to be an advantage, and
you don’t seem to have the risk of someone misunderstanding your
file. Your lab wants Adobe RGB, and that’s what you should give them.
(Dan, how about doing a course in the UK?)
Find me a sponsor, and I’ll be happy to do it.
It seems kind of silly to me that I’ve given small-group
classes in three different European countries, but never in my native
language.
Dan Margulis
___________________________________________________________________________
Date: Wed, 25 Feb 2004 03:01:15 -0500
From:John Castronovo
Subject: Re: Re: Adobe RGB vs. sRGB
As the owner of a digital lab that is quite similar
to the Frontier (an Agfa DLab which is also the Kodak lab you say
you’ve used, Russell) I have some input here. I’ve profiled our
lab, and it’s certainly not sRGB - it’s a little larger with a
gamma closer to 1.8 than 2.5 and a warmer white point.
In our workflow, we prefer to have the client supply
us with files that have embedded profiles so that we can properly convert
them to the lab’s space. Neither sRGB nor AdobeRGB could produce
correct results. This is in spite of the fact that the manufacturer says to
use sRGB and many lab owners do. If you probe deeper, however, you’d
discover that they say to use sRGB1.8 which isn’t even typically
found on most systems (Dan, maybe it’s more common in Germany?).
Russell, the reason many portrait labs want sRGB
files is that it’s quick and easy for them and the photographer. I
tell my customers that the ‘s’ stands for ‘safe’.
The color won’t be a perfect match to the display, it won’t be
the optimal gamut for the printer, but there won’t be many surprises
either. When you’re printing files by the pound for a low price,
that’s all that matters.
The website you mention is full of half truths and
misinformation. For example the concept that if the originating color space
is larger than the destination’s then the out of gamut colors
won’t print at all. This would be true of an absolute rendering (or a
meatball sandwich) which is never done when converting to a smaller space.
Then the claim that all the digital labs are sRGB, which they aren’t.
Then, that the software doesn’t convert color spaces, some do, or
that all labs want sRGB, I don’t and apparently neither do labs in
the U.K.
There’s no motive for such misinformation, just
one’s right to be wrong. They don’t know it because
they’ve never seen better. If people think that a Whopper is a
hamburger, then who am I to confuse them?
john castronovo
tech photo & imaging
___________________________________________________________________________
Date: Wed, 25 Feb 2004 11:04:27 +0000
From: Andrew Haley
Subject: Re: Re: Adobe RGB vs. sRGB
john c. writes:
The website you mention is full of half truths and
misinformation. For example the concept that if the
originating
color space is larger than the destination’s then
the out of gamut
colors won’t print at all.
The oddest thing about the site is that the redering
of the colour space for Epson 2200 clearly shows that there is a
substantial part of the printer’s gamut that is outside sRGB.
[*] However, because the volume of the printer colour space is
smaller than sRGB, you might as well shoot in sRGB! This seems like a
total non sequitur.
Andrew.
[*] Actually, there’s more around the other
side that they don’t show.
___________________________________________________________________________
Date: Wed, 25 Feb 2004 10:00:18 -0500
From:Russell Proulx
Subject: Re: Re: Adobe RGB vs. sRGB
On 25 Feb 2004 at 3:01, john c. wrote:
In our workflow, we prefer to have the client supply us
with files that have
embedded profiles so that we can properly convert them
to the lab’s space.
Neither sRGB nor AdobeRGB could produce correct
results. This is in spite of
the fact that the manufacturer says to use sRGB and
many lab owners do.
Thanks for the great info John! It does make a good
argument for “when in doubt, send it in sRGB”. Obviously
there’s a problem with mis-information that needs correcting.
Russell Proulx
Montreal
___________________________________________________________________________
Date: Wed, 25 Feb 2004 09:11:14 -0600
From: “Cliff White”
Subject: Re: Adobe RGB vs. sRGB
Dan wrote:
—-I just got back from an on-site where the
images
were digital captures of flowers, and CMYK output was
the only consideration.
That type of scenario screams out for something other
than Adobe RGB.—-
Dan, what RGB space does it scream out for?
sRGB or something else?
We are a shop that shoots digital almost entirely for
CMYK output (monthly magazine, some books, pamphlets, etc.) Since
switching to digital capture and boning up w/ Dan’s book and others
we have started doing our own prepress prep of images. We will very
soon be getting our RIP installed to close the loop on that process.
I had been under the impression that, assuming we had
total control of our files, it was better to shoot and work in a
larger-gamut space in order to have more options and control when selecting
what to clip when you convert to a smaller gamut space, be it CMYK, or
another RGB. Is this still a good assumption or is there something
I’m missing?
CLIFF WHITE
Staff Photographer
Missouri Department of Conservation
(573)522-4115 ext. 3854
P.O. Box 180
Jefferson City, MO 65102
___________________________________________________________________________
Date: Wed, 25 Feb 2004 07:32:05 -0700
From: Andrew Rodney
Subject: Re: Re: Adobe RGB vs. sRGB
on 2/24/04 10:51 PM, Dan Margulis wrote:
A couple of months ago, in a significant milestone,
several prominent members
of the group that I call the Conventional Color
Management Wisdom suggested
that at this point, it is proper and desirable to
assume that an RGB file
without an embedded profile is an sRGB file.
Previously, the CCMW had been
that any untagged file is meaningless mystery meat.
I certainly wouldn1t agree with that in total. IF the
file came untagged from a PC user, I1d first assume sRGB. If however the
file came from a Mac user I1d suspect Apple or perhaps ColorMatch RGB.
Anyone using untagged files on a Mac will find sRGB ugly (and vise versa on
the PC with Apple RGB).
These files are still mystery meat and considering
that there are no less than four matrix settings for sRGB in many digital
cameras (including Adobe RGB), the file is still totally meaningless sets
of numbers until a tag is provided that produces what the end user has to
GUESS is the right color appearance.
I don’t think novice users are capable of doing
that, so I recommend that
they stick with sRGB.
Which causes as many problems for Mac users working
with sRGB in non ICC savvy aware applications. If the application is aware,
then the file is tagged, previews correctly and this entire issue is moot.
In your case, there does seem to be an advantage, and
you don’t seem to have
the risk of someone misunderstanding your file. Your
lab wants Adobe RGB, and
that’s what you should give them.
True to a point but this will not allow the user to
soft proof to the device and edit accordingly. Telling the lab yo