Dan Margulis Applied Color Theory

Inadequate Black

disappointing black
Posted by: "Ron Kelly"
Fri Mar 16, 2007 8:45 am (PST)

Folks:

I make calendars and books that are produced on sheet-fed offset. The final results are usually coated with a uv gloss, or laminated. Coated and high quality stocks are used throughout.

My problem is that I don't have the rich blacks that I see in some magazines. Case in point: Sports Car Magazine, a glossy visual treat for those of us who like to dream about driving mid engine Italian thoroughbreds.

The magazine has better blacks than I get on my products.I have taken this up with my off-set company, but they have no answer.

According to Dan Margulis, magazines are commonly produced on a webb press (because of the volume, I should think) and should be constrained to something like 300% TIL. This would seem to tie their hands and give me the advantage with my process, but they beat me hands down.

Because the darkest black is "unavailable" I lose a substantial amount of shadow detail in some pictures. If I want to create an effect like Josuf Karsh, ie a strong low key portrait, I have to somehow engineer violent contrast into the file. This usually upsets the rest of the image because all the channel blending and curving has to bleed back into the rest of the image.

Questions:

1. Are the inks used possibly the reason? The magazine is very glossy, and I'm wondering if they get that from the ink as well as the stock used. I wouldn't think that they could be using a coating applied after the printing, could they?

2. Is there a net effect vis-a-vis the black from the printing order? My off-set uses K first, for what reason I don't know. If the inks are applied in a different order, is the K plate more significant then? What if it were applied last? Is there a best practice with ink order with respect to dmax?

3. Dan has suggested constructing a black of 100K with a lower value of CMY to get a darkest black for some pictures. Is it true that this would only show up on the printed product? I am trying to evaluate various techniques by a digital proof, and it seems to be that no matter how I construct that shadow, it always looks the same darkness at some point. If the file has to be off-set to judge, then I'm wasting my time trying to see it on an ink-jet proof, am I? Would a "composed proof" (I hope that's the right term) show it better?

Thanks for your time and consideration,
Ron Kelly
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Re: disappointing black
Posted by: "Jim Rich"
Fri Mar 16, 2007 10:07 am (PST)

Ron,

The first place to start your detective work is to look at the paper you are printing on. Does the paper allow you to get good rich colors and black areas? If it does then the next place to look is at the color separation. However, if the paper is not capable of giving you the look you want then you have two choices. Live with it or get a better paper. That is usually a financial decision.

In general 4-color printing uses an ink rotation of K, C, M, Y. Specifically, ISO 12647-2 offset printing suggests this ink rotation order. Though it is not mandatory as long as you hit the solid L* a* b* values of the solid ink colors.

As for your color separations. You should inspect the total ink areas and see what the black printer value is in that area. As suggested, using a black with 100% and a lower CMY value would be what to shoot for to arrive at the TAC for your printing process.

In regard to your ink-jet proof, you might want to go back to the paper issue. That is measure the black areas of your printed sheet and the same areas of your inkjet.

One type of measurement to look for is the lowest L* values in the black areas. For example your press sheet might measure an L* value of 10. And the inkjets lowest L* value of 15. If that is the case then you cant get there from here. The inkjet paper you are using is not capable of getting a good black to match your press sheet. The solution is to get a better inkjet paper. This is also a financial decision.

Jim Rich
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Re: disappointing black
Posted by: "Lee Clawson"
Fri Mar 16, 2007 11:43 am (PST)

Ron,

You talk about not having "rich" black but don't say what makes your current black. In addition paper choice and plate order can influence how the deep rich blacks appear. But I'd look first at what makes up your current black.

Lee Clawson
2/\V/\7 Studio
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Re: disappointing black
Posted by: "John Gallagher"
Fri Mar 16, 2007 11:48 am (PST)

Ron,

Assuming as you say that your offset printer is using a high quality coated sheet, then the process ought to be able to print a fairly rich black.

If you are supplying CMYK files to your printer, I would check and make sure the Total Ink on the seps is 340. High quality offset on coated stock can handle 340 to 350 T.I.D. You might want to ask your printer about this. Another issue is what all is running on the same press form. Often one image or area that has problems may force an unwanted compromise in another. For example you have small point size serif type reversing out of black. The pressman may run the black at a lower density to prevent the reversed type from filling in. Matching color on other images on a form can also cause problems elsewhere on the sheet.

Check that the printer can run at least 340 T.I.D., check that the separations are made to that spec.

Check what else is on the form, if for example you have an area of graphics that is well over 340 T.I.D. ( I see designers building rich blacks of 400% !!!) that may force the pressman to run the black down lower. Also make sure that your blacks in the seps are reasonably neutral so that they are not depending on just one or two inks (which may for other reason be run down) to kick up the density.

Finally assuming the separations are o.k. I would ask the printer what densities they are running to and ask for a press sheet with readings written down. It is not your job to diagnose press problems, but if you cannot be there for a live press check - the best way to make sure it gets done right - then ask for some pull sheets so you can check that the Ink densities are within reason. You might then get a second opinion from another printer on the quality of the press sheets. You really need to see full press sheets with color bars to be able to say much about the quality of a press run. I would be particularly interested in what the Black density is, as running the black to low is a fairly common problem and can happen for a variety of reasons, and can definitely destroy the 'rich black' effect you are looking for.

Stock does make a difference and I would also be interested to know what stock is being used. Uncoated offset will give you the worst results as the blacks are weak, flat, and lacking in detail. Coated stocks are better, with better ink holdout and the ability to preserve more detail and more gloss in the inks, but within that group there are variations in quality. Waht grade sheet are they running?

As far as offset vs swop web that is used for most large circulation magazines, properly done, sheetfed offset can out 'rich black' a web press.

Hope this helps clarify some of the issues at least. Good luck.

John Gallagher
Prepress Manager, Val Print
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Re: disappointing black
Posted by: "Ron Kelly"
Fri Mar 16, 2007 1:52 pm (PST)

Lee:

My current black is about 300. I've also tried 320 and 340, with the same results.

80C-70M-70Y-70K and up, 87C,79M, 82Y and 76K, doesn't make any difference. In the deep shadow it's mud, instead of a contrasty steep darkness.

Ron Kelly
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Re: disappointing black
Posted by: "Todd Shirley"
Fri Mar 16, 2007 2:47 pm (PST)

Ron

I guess a very obvious comment might be that you should use 100% black in your rich blacks. Why is your black down so low?

I often use a rich black of 60C-40M-40Y-100K, and I bet it looks a lot richer than 80C-70M-70Y-70K even though it's 50 points lower TAC.

Just a thought...

-Todd Shirley
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Re: disappointing black
Posted by: "J Walton"
Fri Mar 16, 2007 2:47 pm (PST)

On 3/16/07, Ron Kelly wrote:

80C-70M-70Y-70K and up, 87C,79M, 82Y and 76K, doesn't make any
difference. In the deep shadow it's mud, instead of a contrasty
steep darkness.

I wouldn't expect much of a difference there - the black generation is *way* low. Your numbers are asking for mud and that's what you are getting. Your average magazine advertiser probably uses Adobe SWOP V2 to convert, and will *without question* get darker blacks than you because SWOP V2 has a 90% black in the deepest shadows.

But with sheetfed printing and coated paper you have a lot of room for higher densities. Why not talk to your printer about what he recommends for your darkest shadows? If you know who's printing your art you can talk to them about how your files are prepared and can tell them not to run up the black.

I'd say you could easily get away with 90-93% black and a density of 320-330 for your files. And YES you will get richer blacks than a magazine that way!

--
J Walton
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Re: disappointing black
Posted by: "Jim Donovan"
Fri Mar 16, 2007 2:48 pm (PST)

Hi Ron, Way too high as far as c,m&y,that is causing the mud in my opinion. Try 75c,60y,60m and 90ish black.But the key is to make the black 90ish by using a steep curve in the black channel,not by just conversion or black generation or profile.Lock your K curve at 50ish and steepen from 50% up. I do a lot of snowmachine clothing for print that has all the detail in deepest part of the shadows and it works like a charm,even though tid is only 285ish. The c,m,and y are totally useless in deep,deep black shadows. And of course sharpen the crap out of the black plate only,use blend if on a layer if need be to restrict sharpining else where. Dan taught me in his classes, real men use 500,you just need to know where and when. Jim Donovan
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Re: disappointing black
Posted by: "Lee Clawson"
Fri Mar 16, 2007 3:49 pm (PST)

Ron,

That's even more color than I usually have in my "rich" blacks. I usually have about 90K with the others coming in lower than yours.

I hope someone else will write in about plate order. The one you described keeps bothering me. I'm wondering if what you see, a muddy shadow, is quite literally the color we'd get with this plate order.

In this case you (your printer) puts K down first followed by the others. A very dark color that's made from CMY is brownish. Is that the "mud" you speak of ???

Lee Clawson
2/\V/\7 Studio
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Re: disappointing black
Posted by: "Ron Kelly"
Fri Mar 16, 2007 8:37 pm (PST)

Jim:

This sounds like good advice; I'll try it.

It may be that I need to use a 260 or 280 sep with a light black generation and then put a point on the black curve to take the maximum up into the 90's.

Would there be anything wrong with using this for most images? Perhaps I should only use this technique when there's a *lot* of shadow? My work is building products for the tourist market, and so I want happy colours with rich saturation. I don't want to sacrifice brilliant colour for contrasty shadows; I'd like to have them both. Up to this point I have used a light black generation á la Dan Margulis.

The only point no one has addressed so far is how to judge this effect. Obviously, the best proof would be to print a job with this setting. In the long run, that is what I'll do.

My inkjet proofing system lets me down here. I get nice, contrast shadows on my own proofs no matter how I build them. I'm guess I'm going to have to ask my offset printer for a set of proofs that are set up different ways.

Thanks to everyone who's contributed on this thread. I really appreciate hearing from everyone, and I know there are a lot of expert hands on this list.

Cheers,
Ron Kelly
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Re: disappointing black
Posted by: "Louis Dina"
Fri Mar 16, 2007 8:37 pm (PST)

Ron,

I used to send color brochures to a sheetfed press, and our company's main background color was black, so getting a good solid black was critical for us. I always used a rich black for the solid background, usually about 100K, 60-70C, 60-70M, and 50-60Y. This was for a solid black background. Another possibility is to use a 2nd black plate to punch up the black density instead of adding CMY. Most commercial printers have their own preference for a rich black formulation, but the above worked well for me with a number of different printers.

My preferred printer used a KCMY sequence (I think most do) on coated stock on a Komori press and got great, rich blacks. They also understood color management very well and had good profiles, so I usually designed my jobs for them using their profiles. It was nice to have that luxury (which I no longer do).

On our product photos (which also used a lot of black) I tended to use a medium to heavy GCR separation to help keep the image neutral on press (it was industrial machinery with a lot of steel, gray, black and a little color). I'd strive to get the shadows up near 280-300% TIL, but with images, I generally kept the black plate at about 90-95 max after tweaking the CMYK file. Even on images separated with light GCR, I tried to get the neutral shadow areas to have a neutral balance of CMY to beef up the density on press.

On most of our jobs, we applied a gloss or satin aqueous coating (it was the final tower on the press) which did give the brochures a little extra pop and apparent contrast. It definitely made the
blacks look a little deeper.

FWIW, my inkjet proofs always had a little more dynamic range and contrast than I could get on press. But it was always darn close because I was using their supplied custom profile to simulate press output. I measured a rich black density of about 1.9 (L=11) on press, which isn't bad.

Hope something here helps.

Lou Dina
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Re: disappointing black
Posted by: "Jim Donovan"
Mon Mar 19, 2007 8:07 am (PST)

HI Ron, Try it you'll like it. when reducing the c,m,and y in the blacks use selective color,not curves, you will retain those nice saturated colors. Along with deep shadows with detail, the snowmachine clothes I work on has lots of saturated greens, reds and blues and more. Using selective color allows you to keep saturated colors by affecting only the blacks. And yes I always use a light black generation and never,ever anything else with these types of images, good luck Jim Donovan
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Re: disappointing black
Posted by: "mfedecky"
Mon Mar 19, 2007 7:46 pm (PST)

Ron, this might help. My approach to black re CMYK formulas and inkjet proofing is as follows. When I make my separations from RGB to CMYK for "SWOP coated" conditions, I use 300% Total Ink Limit (TIL) and 80-85% Black in "Custom CMYK". After conversion I will steepen the black channel to get me to a maximum of 90% black (and still maintain the shadow detail in the image). The final values would be C= 78 M=66 Y=66 K=90 (TIL=300). For separations printing to a sheetfed press on coated stock the numbers would add up to 340% TIL. I would still maintain the black at 90% and increase the other inks to around C=90, M=80, Y=80, K=90. In both scenarios I get maximum ink coverage, maximum black ink and neutral shadows. This applies to images only. With solid blacks as background colors, the black could go up to 100% and I would ask the printer for their preferred formula for rich black.

Re inkjet proofs, I can get my Epson inkjet printer to simulate samples I have had printed previously with different presses. I've had an ICC profile made for my Epson printer (printing onto photo quality paper to get the dark blacks). So when I print from within Photoshop, the file uses the profile (in conjunction with the Working CMYK) to generate a proof. This gets me in the ballpark at least when it comes to maximum printable shadows. I don't have to send out for printer's proofs to know that my shadows are plugging up.

I also make sure that all the images in the job have similar TIL values, so the printer does have to "ink down" because of one image that's over the limit. Then before the job goes to press I will have the printer print their contract proof which they are obligated to match. If your monitor is calibrated, and you've figured out "soft-proofing" then you need not rely on the inkjet proofs.

Michael Fedecky
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Rich Black for a Black&White image
Posted by: "cbdurr"
Thu Mar 22, 2007 2:58 pm (PST)

I've been lurking around here for about a year and this is my first post, so be gentle! I am working on a piece that will run as 4-color on a Komori offset press. One of the images is a black & white photo which will run adjacent to saturated, full-color images. I'm worried that it will look flat, so I proposed that we use rich black in the darkest shadow areas. There is some concern that the image won't be as crisp because of registration issues.

If you recommend using a rich black, what CMYK values would you try to hit to get a neutral midtones? Any advice on converting a greyscale image to process would be most helpful.

Many thanks,
Crystal Beasley

H O R I Z O N M E D I A G R O U P
. . . . . . . . . . . . . . . . . . . . . . . . .

233 North Eighth Street . Paducah, KY 42001
www.horizonmediagroup.com . 270.443.5383
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Re: Rich Black for a Black&White image
Posted by: Stephen Marsh
Thu Mar 22, 2007 9:12 pm (PST)

Crystal Beasley wrote:

I'm worried that it will look flat, so I proposed that we use rich black in the
darkest shadow areas.

Keep that in mind Crystal, you say the darkest shadows will be rich, the rest K only - is this correct???

There is some concern that the image won't be as
crisp because of registration issues.

The majority of the image has no rego, it is one colour, is it not?

If you recommend using a rich black

The CMY values depend on the stock/ink/tvi etc. Some use SWOP or GRACOL type aimpoints when they don't know any better details.

I thought the midtones were K only, and the deep shadows rich?

What is more critical, density or neutrality?

Regards,

Stephen Marsh.
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Re: Rich Black for a Black&White image
Posted by: "Lee Clawson"
Fri Mar 23, 2007 9:55 am (PST)

Crystal,

There's 2 things that come to mind. One is what we called a "double black". A 2nd sep was made from the darkest areas of the B&W and over-prints the 1st black.

You could also print this as a duotone. Or if 4 process colors are a limit convert to a duotone and then back to CMYK. Then using curves or selective color to bump the black channel. Its not unusual to see a very slight warm or cool tone to these in magazines. That way you have a bit more tolerance for off-neutral casts.

Lee Clawson
2/\V/\7 Studio
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Re: Rich Black for a Black&White image
Posted by: "Henry"
Fri Mar 23, 2007 9:57 am (PST)

More density is possible using all four inks, but that doesn't necessarily mean that the image will appear less "flat" if printed with 4 inks, even when printed along side of a color image. If you wish, you can make a separation having a black plate that exceeds the percentages of the other inks to help keep the image printing neutral. But, a better course might be to make the very best greyscale that you can, printing with black ink only. A comparison of both methods will reveal that they *do* look different, perhaps as they should - a black and white picture is supposed to look different than a color picture.

Printing a well-prepared greyscale may even appear to be less flat. Having only black ink, there is the opportunity for more of the paper to be seen, thus increasing the apparent contrast, compared to an image that has very little of the paper showing between the dots. The paper is the lightest part of the tonal range.

It is most important to make a really good greyscale.

Henry Davis
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Re: Rich Black for a Black&White image
Posted by: "Louis Dina"
Fri Mar 23, 2007 10:26 pm (PST)

Crystal,

If you are running some B&W images in the same print run as 4/C, the press operator will probably set a limit on black to accomodate type or the 4/C images, and this may leave your 1/C B&W images looking a little weak. If you are running only B&W images, you can instruct the printer to bump the black a little to get good density in your images, but you may be more limited when mixing text, B&W and color in the same run. I ran into this once, and at the time I was chicken to try 4/C B&W for fear of color shifts. My B&W's looked rather flat and didn't have the desired density and contrast range I wanted.

As mentioned in another post, you can add a 2nd bump plate with another shot of black in the shadows, or separate with heavy GCR to reduce the possibility of color shift and use 4/C printing on your B&W's for greater density. Your choice of separation will depend on the type of press (sheetfed or web), type of stock, etc.

Lou Dina
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Re: Rich Black for a Black&White image
Posted by: "cbdurr"
Mon Mar 26, 2007 5:11 pm (PST)

Thanks for the excellent responses already. I'm going to try to address the questions posed thus far. Forgive me if this is too much information.

It's going on a sheetfed press, running as 4 color. No extra spot colors are possible on this job, so converting to duotone with a second black isn't an option. There will be CMYK color photos and a little bit of type. The type shouldn't be a problem because I'm setting it in a thin serif on white background. Type is definitely not critical on this piece. Images are the priority. The paper isn't set in stone at this point, but I'm hoping it will go on Utopia 1X Premium gloss with a satin aqueous coating.

The photos are placed into InDesign. I export a postscript which is processed by Apogee.

-Crystal Beasley

H O R I Z O N M E D I A G R O U P
. . . . . . . . . . . . . . . . . . . . .

233 North Eighth Street . Paducah, KY 42001
www.horizonmediagroup.com . 270.443.5383
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Re: Rich Black for a Black&White image
Posted by: "Lee Clawson"
Mon Mar 26, 2007 8:11 pm (PST)

Crystal,

I really like what Henry said, make an excellent B&W. However, if you convert to CMYK in the desire to use more ink and get a the richer black and are unsure of the maintaining gray balance I would look to pushing the balance towards a very slight warm or cool cast.

Lee Clawson
2/\V/\7 Studio
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Re: Rich Black for a Black&White image
Posted by: Henry Davis
Tue Mar 27, 2007 11:12 am (PST)

I understand your suggestion Lee, and it is a good approach in cases where print conditions limit the possibility of neutral printing with four inks.

If CMYK is desired over a well-made greyscale, and if the intent is for it to print as neutral as possible, then a separation that maintains black at a higher percentage than CMYK will help keep the image neutral. If the image is slightly biased to either warm or cool, it could get out of hand. If it is so slight a bias that the press operator believes that it is supposed to be neutral, then other elements on the sheet may be altered in the attempt to make the suspected neutral element print neutral. It could even go the other way - it is biased a little warm or a little cool and during the run it becomes too warm or too cool? With black leading the bias, neutral has a pretty good chance.

As I said before, I wouldn't give up on well prepared greyscales. They are what they are, and well-made ones are appealing. The trade-off for higher density(4-color) can sometimes be less apparent contrast, which ironically is one of the goals of higher density 4-color approach.

Henry Davis
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Re: Rich Black for a Black&White image
Posted by: "Lee Clawson"
Tue Mar 27, 2007 3:46 pm (PST)

Henry,

The more you respond to this the more I want to tell her to ignore me and follow your ideas. I had hoped that Crystal would have understood that I was thinking of an analogy to a B&W "toned" print. And then, along with a proof, the idea would be explained to the printer.

In the mean time I finally came up with an idea for this that I like and minimizes some possible bias problems. (sent this earlier Off-List, **see below)

Lee Clawson
2/\V/\7 Studio
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** Here's what was sent Off-List:

Crystal,
Here's some more info.

You can make grayscale file. And then convert it to a CMYK file that only prints from the black channel of the CMYK file*.

And then make a mask from the darkest tones, those from 90 to 100% black. This is used on the CYM channels to add ink. The added ink only prints where the black channel is 90 to 100% and gives you a rich looking black.

The amount added in the CMY channels could be 20 to 30% of each color. For example it might read 20C-20M-20Y and 100%K.

Below 90%K there would be no tones in the CMY channels.

Lee

*-- If you simply do a straight conversion to CMYK it won't work. You have to make the grayscale file into multi-channel. Then from the "Channel" palette add 3 channels. And then make sure your original B&W is in the 4th channel (you can select it and drag it down in the channel palette).

Then with this multi-channel file you convert it to CMYK. If you inspect the channels individually you'll see blank CMY and all the image on the black channel.
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Re: Rich Black for a Black&White image
Posted by: Henry Davis
Tue Mar 27, 2007 4:07 pm (PST)

On Mar 27, 2007, at 1:34 PM, Lee Clawson wrote:

I was thinking of an analogy to a B&W "toned" print. And then, along with a
proof, the idea would be explained to the printer.

It is an interesting approach, especially if the halftone dots would actually lay directly on top of each other. The point I am making is that when more paper that is seen between the dots, the more apparent contrast the image has. A well-prepared greyscale(one that has been made to have good contrast) will achieve this. Preparing a good greyscale is not quite as easy as it may seem. Of course it won't look the same as a color picture, but that is the point - it isn't the same. It seems to me that there is more made of this notion of avoiding printing greyscale pictures now than there has been in the past. The newer crop of designers maybe haven't consulted with their predecessors about this. If others perceive this to be the case, I would like to know.

Converting it to CMYK will allow for less paper to be seen between the dots. One option that is used, thought it may not be an option in Crystal's case, is to use a spot color black ink that itself has a higher density than a normal black. This isn't very cost-effective, but has been done for specialty printing. The same, but opposite, trick is used for simulating original pencil illustrations where the regular black ink may be too dense - an extended, less dense spot black is used to more closely match the original art. Again, it is a specialty, and not for normal projects.

Henry Davis
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Re: Rich Black for a Black&White image
Posted by: Dan Margulis
Wed Mar 28, 2007 6:17 am (PST)

Henry writes,

Preparing a good
greyscale is not quite as easy as it may seem. Of course it won't look
the same as a color picture, but that is the point - it isn't the same.
It seems to me that there is more made of this notion of avoiding
printing greyscale pictures now than there has been in the past. The
newer crop of designers maybe haven't consulted with their predecessors
about this. If others perceive this to be the case, I would like to know.

The biggest objection to just printing grayscale when 4/c is available is not so much contrast as a coarser appearance, particularly at lower screen rulings. In a newspaper, mixed color and B/W images on the same page can create the illusion of two different printing processes, particularly in the quarter- to midtone areas. A 4/c B/W looks somewhat smoother in these areas than one printed K only, and this sways some designers to use 4/c B/w when it appears on the same page as color photographs.

As for adding contrast by adding inks, it's not a very big deal--95K is plenty dark if the printing conditions are good. But if anyone wanted to squeeze the last drop out, one option would be to create a good B/W, paste it into the black channel of a blank CMYK document, and then Convert to Profile, Custom CMYK, Maximum GCR, Maximum Black=100%, and 50% UCA. This would put a dollop of CMY into the deepest shadows for added darkness, but otherwise the picture would be K only.

Dan Margulis
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Re: Rich Black for a Black&White image
Posted by: "Lee Clawson"
Wed Mar 28, 2007 7:55 am (PST)

Dan,

The "dollop" of CMY in the deep shadows is what I'm suggesting be achieved with the multi-channel method. Your idea sounds easier.

Lee Clawson
2/\V/\7 Studio
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Re: Rich Black for a Black&White image
Posted by: Henry Davis
Wed Mar 28, 2007 9:37 am (PST)

On Mar 28, 2007, at 8:10 AM, Dan Margulis wrote:

The biggest objection to just printing grayscale when 4/c is available is not so
much contrast as a coarser appearance, particularly at lower screen rulings.
In a newspaper, mixed color and B/W images on the same page can create
the illusion of two different printing processes, particularly in the quarter- to
midtone areas. A 4/c B/W looks somewhat smoother in these areas than one
printed K only, and this sways some designers to use 4/c B/w when it appears
on the same page as color photographs.

This is a matter of taste, and to each his own. Personally, a well-made greyscale is a nice thing to see in print.

What I have been noticing is a gradual increase in attempts at 4-color neutral pictures, and for the most part, they are not very well made. For these designers, a good greyscale would have been the better option than a lackluster, flat poorly-made 4-color. It's as if designers seem to want something that they don't understand, or, and here is a big guess - they understand that their job will print on a 4 color press and somehow assume that a greyscale must be converted to CMYK. A "canned" conversion is made, and the printed result is disappointing. It is a trend that seems to be going around. You would think that making a real good greyscale would be enough of a challenge, but nooo.

As for adding contrast by adding inks, it's not a very big deal--95K is pretty
dark if the printing conditions are good. But if anyone wanted to squeeze the
last drop out, one option would be to create a good B/W, paste it into the black
channel of a blank CMYK document, and then Convert to Profile, Custom
CMYK, Maximum GCR, Maximum Black=100%, and 50% UCA. This would
put a dollop of CMY into the deepest shadows for added darkness, but
otherwise the picture would be K only.

This is a real good method. It is easy for some to understand, but may not be the kind of task that would appeal to a lot of designers. Once again, you have put it out there for anyone to take advantage of, and those who want to set their work apart from the rest of the pack will do so. Unless Custom CMYK disappears.

Henry Davis
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Re: Rich Black for a Black&White image
Posted by: "Louis Dina"
Wed Mar 28, 2007 10:24 am (PST)

Henry....a question, not a rebuttal. I have sometimes been disappointed by the results I have gotten with a well made grayscale on a 4/C sheetfed press using process black. And this is with a pretty good printer. At least the few times I tried it, (a mixture of 4/C images, grayscale and text), my grayscales lacked the dynamic range and pop I expected and looked a little flat and weak in the shadows. These grayscale images definitely were full range. Maybe it is the way the pressman ran the black, or didn't want to plug up other images, text, or whatever. If I recall, the best density you will get using process black without any supporting CMY inks is about 1.7. If they run light on the black, it will be even less leading to washed out look.

That is the main reason I have gone to 4/C B&W images on press, but I convert to CMYK using heavy GCR and a moderate TIL to keep CMY components from climbing too high, and tweak the image and check grayscale balance in CMYK before submitting it. If I had a job that was solely B&W, without any color images, I might be more inclined to try grayscale again, and possibly ask the printer to use a different black (instead of process black) for some added punch.

I'd be interested in your comments.

Thanks,

Lou Dina
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Re: Rich Black for a Black&White image
Posted by: Henry Davis
Wed Mar 28, 2007 12:47 pm (PST)

On Mar 28, 2007, at 12:24 PM, Louis Dina wrote:

Henry....a question, not a rebuttal. I have sometimes been
disappointed by the results I have gotten with a well made grayscale on
a 4/C sheetfed press using process black. And this is with a pretty
good printer. At least the few times I tried it, (a mixture of 4/C
images, grayscale and text), my grayscales lacked the dynamic range and
pop I expected and looked a little flat and weak in the shadows. These
grayscale images definitely were full range. Maybe it is the way the
pressman ran the black, or didn't want to plug up other images, text,
or whatever. If I recall, the best density you will get using process
black without any supporting CMY inks is about 1.7. If they run light
on the black, it will be even less leading to washed out look.

1.7 is a proper target density for black, but you are right that for a particular run, black density may actually be less or more. The density of the ink itself may be less an issue than is the gain - either more gain or less gain. You might expect that black will plug somewhere above 95 percent, and pushing the ink on press will have more effect on this end than it will in the highlights.

I know what you mean. There are "art" books about black and white photography that have flat looking, washed out greyscale pictures. The photographer was probably disappointed.

But then, what is the maximum density to be had on various black and white photographic print papers used for traditional enlargements (2.0ish?)? Contrast expectation is more for some photo papers than on others (I am not a photographer, so I'm out on a limb here). Offset printing is just different, and it is a project to figure out the best way to imitate black and white photography with offset.

You might expect density of 2.0 - 2.2 for 400 percent ink, which isn't going to print without problems, if at all.

I am also a fan of 4/c neutral images that are well-made, and used in the right context, but I still hold out that good greyscale printing can be done.

That is the main reason I have gone to 4/C B&W images on press, but I
convert to CMYK using heavy GCR and a moderate TIL to keep CMY
components from climbing too high, and tweak the image and check
grayscale balance in CMYK before submitting it. If I had a job that
was solely B&W, without any color images, I might be more inclined to
try grayscale again, and possibly ask the printer to use a different
black (instead of process black) for some added punch.

But then Louis, you know what you are doing.

For what it's worth, I like to use a well-made greyscale for side-by-side comparison of the same picture that I am making into a 4/c neutral. This seems to tip me off if I am getting away from the goal.

Gloss overcoating often helps greyscales (and color) pop a little better.

Just pressing the button for conversion to CMYK will cause more of the paper to get ink in the mid-tones and in the highlights. The paper is the lightest tone available. Eliminating the lightest tone, risking grey-balance, and muddying up the picture isn't very nice. I see more of this than in the past, and wondered why. Your experience, and your disappointment in greyscale is appreciated. Your solution is well thought out and reasoned too.

Half-tone dots aren't continuous-tone, and a good imitation is not always easy. Folks don't seem to like those dots.

Henry Davis
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Re: Rich Black for a Black&White image
Posted by: "Lee Clawson"
Wed Mar 28, 2007 8:06 pm (PST)

on 3/28/07 3:56 PM, Henry wrote:

But then, what is the maximum density to be had on various black and
white photographic print papers used for traditional enlargements
(2.0ish?)? Contrast expectation is more for some photo papers than on
others (I am not a photographer, so I'm out on a limb here). Offset
printing is just different, and it is a project to figure out the best
way to imitate black and white photography with offset.

A regular B&W print would be about 1.8 with added density with gloss paper, 2 to 2.1. There are some specialty papers that are a slight bit higher but for the most part 1.8 to 2 is more typical.

I am also a fan of 4/c neutral images that are well-made, and used in
the right context, but I still hold out that good greyscale printing
can be done.

I think the designers, myself included, are seeing a lot more in fashion & hi-technology advertising. The rich looking print compared to usual B&W is appealing. And as you suggest the added over-coating really helps.

If I could make one suggestion it would be to look at the paper choice. Very good paper can make a big difference.

Lee Clawson
2/\V/\7 Studio
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Re: Rich Black for a Black&White image / double dot black
Posted by: Dan Remaley
Thu Mar 29, 2007 8:10 am (PST)

Here©ˆs another thought- we used a technique called Œdouble dot black©ˆ, using black twice as if it were a duotone. Adjusting the contrast of the second black accordingly.

Dan Remaley PIA/GATF
412.259.1814
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Re: Rich Black for a Black&White image
Posted by: "michael.aery"
Thu Apr 26, 2007 9:42 am (PST)

I understand the purpose of choosing Max GCR, Max Black, and UCA 50%.

I've also tried changing each of these settings and I have a good grasp of how it affects my images.

But I'm not sure why one should paste the B/W into the K of a new CMYK doc.

Are there any specific advantages to the paste into K that I'm missing if I skip that step and Convert to Profile straight from the B/W?

I've tried it both ways and it appears that the paste into K step restricts the added inks slightly more than a straight Convert.

But I haven't used this technique in production yet. I just want to make sure that skipping the paste into K step is not a mistake.

Regards,

Michael Aery
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Re: Rich Black for a Black&White image
Posted by: Dan Margulis
Fri Apr 27, 2007 2:46 pm (PST)

Michael Aery writes,

I understand the purpose of choosing Max GCR, Max Black, and UCA 50%.

I've also tried changing each of these settings and I have a good
grasp of how it affects my images.

But I'm not sure why one should paste the B/W into the K of a new CMYK
doc.

Are there any specific advantages to the paste into K that I'm missing
if I skip that step and Convert to Profile straight from the B/W?

In this case we are assuming that the B/W original is correct as is and all we wish to do is add CMY to the deep shadows.

Converting to CMYK with these settings directly from the grayscale will give the same results as pasting the B/W into the black channel of an otherwise blank CMYK document and converting that, *provided* that the dot gain setting in the user's grayscale workspace matches that of the black ink dot gain in the Custom CMYK that he is using.

While such a setup is definitely recommended, many users have settings that differ. If so, the two methods would yield different results, and since we accept as a given that the original B/W is correct, converting the grayscale to CMYK directly would give these users an incorrect result, whereas pasting and then converting would work.

Dan Margulis