Date: Thu, 05 Sep 2002 16:33:36 -0000
From: "zumbadan"
Subject: degrading files
Quick question. If color adjustments are done without using an adjustment layer, how much degradation takes place. If the file is not saved as the original, or is not saved at all, does the original still get degraded.Dan Zimmerman
www.brisleyart.com
Date: Fri, 06 Sep 2002 18:34:19 -0400
From: "Jerry L. P'Simer"
Subject: Re: degrading files
zumbadan wrote:> Quick question. If color adjustments are done without using an
> adjustment layer, how much degradation takes place. If the file is
> not saved as the original, or is not saved at all, does the original
> still get degraded.If it is your opinion that an image needs help through editing (color correction). Why on earth would you consider this to be a degradation? And if so why edit in the first place?
Jerry P'Simer
Date: Sat, 07 Sep 2002 01:41:48 -0000
From: "zumbadan"
Subject: Re: degrading files
"Jerry L. P'Simer" wrote:
> If it is your opinion that an image needs help through editing (color
> correction). Why on earth would you consider this to be a degradation? And
> if so why edit in the first place?Jerry, I have heard numerous times that making alot of corrections to a file degrades it. To quote Bruce Fraser "when you use Adjustment Layers to edit the image, all the edits are calculated at the same time when you flatten the image. This approach degrades the image much less than burning successive rounds of corrections into the image one by one."
For this reason I use adjustment layers. However, I personally cant see much of a difference in side by side tests. I prefer to work without using layers. If file degradation is an insignificant difference then I would go ahead without worrying. I posed my question because I would like to know for sure.
If there is a significant difference, then I am interested in knowing if an original can be corrected and the file saved as something else without affecting the original. I do not think color correcting is degrading in itself, or as you say, why would I do it?Dan Zimmerman
www.brisleyart.com
Date: Fri, 6 Sep 2002 20:18:52 -0700
From: Lee Varis
Subject: Re: Re: degrading files
On Friday, September 6, 2002, at 06:41 PM, zumbadan wrote:> Jerry, I have heard numerous times that making alot of corrections
> to a file degrades it. To quote Bruce Fraser "when you use
> Adjustment Layers to edit the image, all the edits are calculated at
> the same time when you flatten the image. This approach degrades the
> image much less than burning successive rounds of corrections into
> the image one by one."
>
> For this reason I use adjustment layers. However, I personally cant
> see much of a difference in side by side tests. I prefer to work
> without using layers.It is a common misconception that using "adjustment layers" is somehow less destructive than simply doing the same edits one after the other. In order for multiple adjustment layers to work at all the transforms applied by each successive layer HAVE to be calculated sequentially - one after the other. There is no difference once the file is flattened or sent through a printing rip to doing the same corrections directly on the file one after the other.
The advantage of using adjustment layers is really the ability to revise a correction later without re-applying (you edit the layer and its like applying a new correction to the original file instead of making an additional successive adjustment) - Thats it!
Stacking up adjustment layers is just as destructive as applying multiple adjustments and should be avoided to the same degree. If, however, you gain some advantage using other features of layer work (layer masks, blending options, ect..) than it may be desirable to use layers rather than successive edits.
regards,
Lee Varis
http://www.varis.com
888-964-0024
Date: Sat, 07 Sep 2002 06:11:24 -0000
From: "zumbadan"
Subject: Re: degrading files
Thanks LeeI figured that was the case. When I was first starting out last year with color editing I did so much trial and error that Im sure using layers at that time might have helped. Now it definately makes no difference except as you say to re-edit individual layers.
Dan Zimmerman
Lee Varis wrote:
> It is a common misconception that using "adjustment layers" is somehow
> less destructive than simply doing the same edits one after the other.
> In order for multiple adjustment layers to work at all the transforms
> applied by each successive layer HAVE to be calculated sequentially -
> one after the other. There is no difference once the file is flattened
> or sent through a printing rip to doing the same corrections directly on
> the file one after the other.
Date: Sat, 07 Sep 2002 01:53:21 -0600
From: Ron Kelly
Subject: degrading files
zumbadan wrote:> Jerry, I have heard numerous times that making alot of corrections
> to a file degrades it. To quote Bruce Fraser "when you use
> Adjustment Layers to edit the image, all the edits are calculated at
> the same time when you flatten the image. This approach degrades the
> image much less than burning successive rounds of corrections into
> the image one by one."For what it's worth, yes, an image is "degraded" by editing. Editing color on computer neccessarily reduces the information in the file. However, this is not REALLY degrading it anymore than throwing out the trash is degrading your household. You're getting rid of something you don't want. Adjustment layers have the added benefit of being reversible, so if you found that something valuable was in the trash you can retreive it.
> For this reason I use adjustment layers. However, I personally cant
> see much of a difference in side by side tests. I prefer to work
> without using layers. If file degradation is an insignificant
> difference then I would go ahead without worrying. I posed my
> question because I would like to know for sure.Ah, for sure. I'm beginning to think there is no such thing, for sure.
Computers allow us to see "into" very dark corners when we zoom. When do we pass "significance"? There is no certainty on this point.
Use adjustment layers, my friend. You've got little to lose and much to gain.
When you want to send a "lean" file such as a tif or jpeg, lose the layers and your output is as small and as good as it can be. And you will have "a way back" if you need it.
Ron Kelly
Date: Sat, 07 Sep 2002 15:54:35 -0000
From: "zumbadan"
Subject: Re: degrading files
Thanks RonI probably will keep using layers for most projects. I still have one question. If you do an edit and then reverse it, has that action affected the file or does the reversal return the file to its original state.
I know how hard it is to justify significance. In my case I work for an artist who is a perfectionist. Significance would be any loss of percieved detail, another hard to justify concept.
Dan Zimmerman
www.brisleyart.comRon Kelly wrote:
For what it's worth, yes, an image is "degraded" by editing. Editing
> color on computer neccessarily reduces the information in the file.
> However, this is not REALLY degrading it anymore than throwing out the
> trash is degrading your household. You're getting rid of something you
> don't want
Date: Sat, 07 Sep 2002 11:56:51 -0500
From: David Riecks
Subject: Re: Re: degrading files
zumbadan (really Dan Zimmerman) wrote:>If there is a significant difference, then I am interested in
>knowing if an original can be corrected and the file saved as
>something else without affecting the original. I do not think color
>correcting is degrading in itself, or as you say, why would I do it?
I think there is one fatal assumption that you are making that needs to be addressed. Not everyone is color correcting images for one and only one type of output! There are many of us on the list (I believe) that are scanning and color correcting for "multiple output."
I do a lot of work preparing images that are intended for several different "flavors" of 4-color output (web offset coated, sheetfed coated, newsprint, etc) but I also prepare images for large-format inkjet (epson & HP plotters), Direct digital printing (Chromira, Pegasus), and even film recorders (LVT, Solitaire). Thus I alway begin work and save my archives in RGB.
Each of these devices have different requirements (CMYK for some, RGB for others) and corrections for one may be moving 45, 90, or even 180 degrees from what needs to be done for one of the others. Case in point, I tend to prepare images containing Skin-tones with the idea that they will be converted to CMYK and offset/sheetfed printed on coated stock. Thus I tend to follow the guidelines of Yellow equal to or 15-25 percent higher than the Magenta value, with the Cyan at 1/3 to 1/5 of the Magenta value. However, when I send RGB files prepared this way (with offset as the intention) for output on a local labs Chromira (printing on Fuji Crystal Archive photo paper) the skintones print extremely yellow. After running a number of tests, I've concluded that these images need significantly more Cyan, and Magenta that what I would normally do for standard color offset printing (these seem to be "programmed" for what most digital cameras create which makes sense).
In this situation, I've found that prepping the image to a point where the yellow and magenta are about equal, with the Cyan about 1/3 to 1/4 of the M/Y value gives me a good "base" image. I can then save two curve adjustment layers, one for Chromira, and one for offset in the same file (naming them for convenience). The "Press" setting swings the yellow value higher and cyan lower, and the "photo" setting keeps the cyan value high and swings the magenta value higher.
This way I don't have to create and store two versions of the same image (at least till the client needs it) or go back and "re-process" an image and risk "degradation" or worse yet, have to go back and scan again.
With the advent of "hexacolor" printing, and clients that need the same image used for both printed pieces as well as banners, web-use, etc.
Adjustment layers make life so much easier that I can't imagine not using them.Hope that helps.
David
David Riecks
http://www.riecks.com, Chicago Midwest ASMP membe
Date: Sat, 7 Sep 2002 16:08:24 -0400
From: Dolores Kaufman
Subject: Re: Re: degrading files
Jerry,If you make color corrections to a file and "Save" the file at any point, those corrections will be saved with the file and the file will undergo some degree of degradation from its original state. If you do a "Save As", however, BEFORE any "Save", the original file will remain untouched and you will be creating a new file. Be sure to give it a new name.
Saving with an adjustment layer also preserves the original file (which resides on the bottom layer). None of your "Saves" will alter that layer unless you flatten the file and save it with the same name. You can store that layered file indefinitely (for later edits) and choose to flatten a copy, or flatten and "Save As", which will leave the layered file un-flattened. I prefer to use adjustment layers for several reasons. First, you can go back and see what you did to "correct" it. Secondly, you can go back and tweak it further if you find out after printing that it needs further correcting, and third, you can use the same file for a completely different purpose without degrading it further. Yes, I do believe that successive edits can degrade a file. Just take a look a the histogram after changing an RGB file to CMYK, then back to RGB again - especially after an edit or two. You'll find that it's getting pretty chewed up.
Dolores
On Friday, September 6, 2002, at 09:41 PM, zumbadan wrote:
> Jerry, I have heard numerous times that making alot of corrections
> to a file degrades it. To quote Bruce Fraser "when you use
> Adjustment Layers to edit the image, all the edits are calculated at
> the same time when you flatten the image. This approach degrades the
> image much less than burning successive rounds of corrections into
> the image one by one."
Date: Sat, 07 Sep 2002 17:29:57 -0500
From: David Riecks
Subject: Re: Re: degrading files
zumbadan (really Dan Zimmerman) wrote:>I probably will keep using layers for most projects. I still have
>one question. If you do an edit and then reverse it, has that action
>affected the file or does the reversal return the file to its
>original state.Dan:
In theory if you have thrown out some data from an image file, and then try to "recreate" it afterwards (not an "undo") you may get it close to the same state, but it is not the original. Depending on the extent of the original change it may simply not be possible. If you want to test this, take the original file, duplicate it, perform the state change and then attempt to "recreate" the original. Then using the move tool "drag" the recreation on top of the original. Set the "layer mode" to "difference. If you have a totally solid black image, then the two are the same, pixel for pixel. Any parts of the image that have changed will show up as various colors or white lines.
I recall not too many years ago, when asked this question about resolution. A video artist was working on some items for print, and decided it was taking too long, so he kept the height and width the same, downsampling the file to a lower resolution, and then "upsampled the final to the original resolution. He was very unhappy with the results, but didn't understand why, because it "looked good on his screen"!!
In reality, depending on the form of output, these changes may not be that noticeable, especially if you have nothing to compare the final to. If you have a deeply saturated image that was scanned RGB, convert to CMYK, and then convert back to RGB to print out on a large format inkjet; you may not notice the loss of color. However if you compared it to an image done from the original RGB, you would probably notice the difference right away.
In your case if the artist you are working for compares the finished printed piece to his original painting or watercolor, he's probably going to notice differences. The best you can hope for is something that remains as "true" to original as possible.
David
David Riecks
http://www.riecks.com, Chicago Midwest ASMP member
Date: Sat, 07 Sep 2002 12:36:45 -0600
From: Ron Kelly
Subject: Re: Re: degrading files
zumbadan wrote:> I probably will keep using layers for most projects. I still have
> one question. If you do an edit and then reverse it, has that action
> affected the file or does the reversal return the file to its
> original state.Not if you use an adjustment layer. Say you have your white point set to 2,2,1 but then later you decide that it should be 5,2,2. No problem, you just go back to the adjustment layer. No loss of data, good as new.
Ron Kelly
Date: Sun, 08 Sep 2002 00:50:02 -0000
From: "zumbadan"
Subject: Re: degrading files
Thanks Everyone. My questions have been answered and then some. Now if I could just get an answer to the other 4,562 questions I have this whole business would be a piece of cake.Dan Zimmerman
www.brisleyart.com
Date: Sat, 07 Sep 2002 21:20:49 -0400
From: Jerry P'Simer
Subject: Re: Re: degrading files
Dolores Kaufman wrote:> If you make color corrections to a file and "Save" the file at any
> point, those corrections will be saved with the file and the file will
> undergo some degree of degradation from its original state.This is actually an old argument that for me is still quite lame. Certainly any edit will alter an image from its original state but in no way does it cause damage or degredation if the edit is worthy and makes the file correct for its intended output. It is my belief that if an image is incorrect at the start than it is already a degraded or damaged image and it would be my purpose to fix it through editing.
Jerry
Date: Mon, 09 Sep 2002 09:25:29 -0400
From: Ric Cohn
Subject: Re: Re: degrading files
> Dan Zimmerman wrote:> Jerry, I have heard numerous times that making alot of corrections
> to a file degrades it. To quote Bruce Fraser "when you use
> Adjustment Layers to edit the image, all the edits are calculated at
> the same time when you flatten the image. This approach degrades the
> image much less than burning successive rounds of corrections into
> the image one by one."As I understand it, this is one of the rare times that Bruce mis-spoke. Adjustment layers are great, and they let you try a lot of different things over a longer period of time without committing to changes. They also let you see all the corrections working together so it is possible that you can avoid correcting for earlier "corrections", which would definitely damage the data. However, AFAIK when the adjustment layers are committed, Photoshop applies them one at a time as it flattens the file.
I always keep an untouched bottom layer in case I feel there might be a different interpretation of the image or I decide that I messed up the original correction in some way.
Ric Cohn
http://www.riccohn.com
212.924.4450
Date: Mon, 09 Sep 2002 16:51:37 -0600
From: Karl Snyder
Subject: Re: Re: degrading files
Ric Cohn wrote:>As I understand it, this is one of the rare times that Bruce mis-spoke.
>Adjustment layers are great, and they let you try a lot of different things
>over a longer period of time without committing to changes. They also let
>you see all the corrections working together so it is possible that you can
>avoid correcting for earlier "corrections", which would definitely damage
>the data. However, AFAIK when the adjustment layers are committed, Photoshop
>applies them one at a time as it flattens the file.One trick to flatting when you do not want to flatten is to make a new layer...say a top layer - make it the active layer, then HOLD down the [ALT] while (don't let the mouse button up until this next step is done, click on the Layers menu button and move the mouse down to the "Merge visible" option...THEN LET THE MOUSE UP. You have now "merged all vi sable layers" to this layer without destroying the existing one below...your original and all the adjustment layers.
Don't know if this helps, but it is not well documented.
Karl Snyder
Boulder, Colorado
http://www.RockyMountainNationalPark.Info
http://www.EstesPark.US/
http://www.EstesParkWeddings.com/
http://www.MtEvans.Com/
Date: Mon, 9 Sep 2002 19:25:35 -0400
From: Michael Demyan
Subject: Re: Re: degrading files
I find it easier just Linking the layers I want flattened and if I want to, hiding the layers I don't want to flatten before clicking on "merge visible". You still have the other layers (visible or not) as part of the file.M. Demyan
> One trick to flatting when you do not want to flatten is to make
> a new layer...say a top layer - make it the active layer, then
> HOLD down the [ALT] while (don't let the mouse button up until
> this next step is done, click on the Layers menu button and move
> the mouse down to the "Merge visible" option...THEN LET THE MOUSE
> UP. You have now "merged all vi sable layers" to this layer
> without destroying the existing one below...your original and all
> the adjustment layers.
Date: Tue, 10 Sep 2002 14:06:00 -0400
From: Ric Cohn
Subject: Re: Re: degrading files
My preferred way to make duplicate layers is:
Command A> Command C> Command-Shift-V. This puts a copy of all visible layers into a new layer.Hope this helps.
Ric Cohn"Michael Demyan" wrote:
> I find it easier just Linking the layers I want flattened and if I want to,
> hiding the layers I don't want to flatten before clicking on "merge
> visible".
Date: Thu, 12 Sep 2002 18:06:44 -0400
From: Dolores Kaufman
Subject: Re: Re: degrading files
Jerry L. P'Simer wrote:> This is actually an old argument that for me is still quite lame. Certainly
> any edit will alter an image from its original state but in no way does it
> cause damage or degredation if the edit is worthy and makes the file correct
> for its intended output. It is my belief that if an image is incorrect at
> the start than it is already a degraded or damaged image and it would be my
> purpose to fix it through editing.Jerry,
I apologize for misdirecting my comments to you when they were really meant for Dan who wanted to know if a file would be changed, or degraded, once an edit had been saved. (I forgot to mention in my remarks that if he is working in Photoshop 5.5 or later, he can use the history palette to undo most edits (even if saved) as long as the file remains open.
In response to your comments above; believe it or not, I agree with you wholeheartedly. I think the operative words here are ' if the edit is worthy and makes the file correct for its intended output.'
I alter nearly every file I open, as virtually nothing arrives onto my hard drive, whether from film or a digital camera, in a perfectly balanced or 'Best That It Can Be' condition. I never think of what I do as "degrading" the image, but I have learned to follow certain procedures to avoid doing so. When I was fumbling around in the beginning I dare say I degraded more than an image or two until I gained a better grasp of what I was doing. By the way, Dan (Margulis)'s book "Makeready" was a great help in this regard.
I would still maintain that you want to work in a manner that allows you to apply a minimum number of successive edits to an image. This is why, from my perspective at least, adjustment layers and the history palette were the most useful additions to Photoshop.
Respectfully,
Dolores
Adobe Photoshop training classes are taught in the US by Sterling Ledet & Associates, Inc.