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Archive 2013 · Why essentially no discussion about CYMK?

nolaguy
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p.1 #1 · Why essentially no discussion about CYMK?

Hi guys and gals,

Accurate color has never been a strength of mine and I probably know a tiny fraction of what most here do about color space. That said, pardon (and correct me) if this post/poll should have been worded differently.

I just uploaded InDesign files for a CD packaging project and it occurred to me I rarely see any mention of the CYMK color model on FM and when I do, it's almost always Mr Gardner providing the information.

I'm curious about the perceptions and practices of FMer's on the topic and further, if I'm even asking the right question. For print, do you RGB or CYMK?

Cheers,

Chuck

May 18, 2013 at 01:39 PM

river rover
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p.1 #2 · Why essentially no discussion about CYMK?

Well, I'm a graphic designer in real life as opposed to a photographer and I can tell you that if output is to a press from an InDesign file I will convert to process color, otherwise I leave in RGB. Most photo print shops use inkjet, lambdajet or traditional methods for printing, not an offset press which is the main reason you would convert. If you're submitting your photo to a magazine for publication, most printers would rather do the conversion themselves.

Mark

May 18, 2013 at 01:48 PM

BruceF99
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p.1 #3 · Why essentially no discussion about CYMK?

I use WHCC to print and they use aRGB files. No reason to convert to CMYK for this kind of printing as river rover mentioned.

May 18, 2013 at 01:59 PM

Peter Figen
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p.1 #4 · Why essentially no discussion about CYMK?

Most photographers never send images to an offset press and don't know squat about how to use CMYK anyway, so they tend not to talk about it. I've spent the last seventeen years learning as much as I can about CMYK and have become extremely good at prepping files for all sorts of different presses. If there's anything you'd like to know, ask away. I can probably address it. There's a lot more to it than just a simple mode change. There's black generation. There's black width. There's total ink. There's making and modifying custom profiles. I can't tell you how many print shops make their profiles (when they make them at all) with the default settings in ProfileMaker and never think how those might not be the best settings, but actually most the so called experts in the print shops never really think much outside the box and only know what the previous employee in their position taught them.

Magazines in the U.S. actually have more or less settled on some rough printing standards, but sheetfed higher end printers are all over the map with each one clinging desperately to their own personal standard in a misguided effort to somehow be a little better than their closest competitor.

May 18, 2013 at 03:10 PM

cgardner
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p.1 #5 · Why essentially no discussion about CYMK?

Printers use subtractive CYMK inks or variants but profile based color management has make it unnecessary to "think" of color in terms of CYMK interactions. I do because I started in graphic art in the 1970s doing color separations and color management manually. I thought of color in CYMK dot percentages for about 20 years before getting Photoshop V1 in the early 90s and working in RGB and used Photoshop for creating CYMK files for printing offset.

Editing in CYMK on desktop color managed applications like Photoshop is often misunderstood and misrepresented because of the way CYMK printer profiles compress gamut when RGB > CYMK >RGB "round trip" edits are done. But there are wide-gamut CYMK gamuts available for editing. See: http://www.curvemeister.com/tutorials/widegamutcmyk/ Dan Margulis book "Professional Photoshop" is also a good one for understand CYMK and when it is useful to edit in that mode when making selective color adjustments. But for most things working with RAW is simpler.

With offset printing each press / paper / ink combination needs to be profiled, just like an ink jet printer using a custom paper the printer doesn't have a stored profile for. There are standards like SWOP for inks and papers for proofing, but for actual production a wide range of papers are used and the print shop must have a profile for each one. Different presses also have different characteristics. The same photo printed on the cover printed sheetfed will need to be separarted into CYMK using a different profile than the copy in the web printed text because the inks / paper / press variables like dot gain differ. The profile for the press will also include things like "Gray Component Removal" or GCR which is used to reduce ink useage and make color control during a long press run more consistent. It involves removing percentages C+M+Y in dark colors with combine to form gray and replacing them with more K (black) ink. That saves the printer money and color varies less. The viewer of the magazine doesn't notice the difference.

Those technical aspects of the printing process which most photographers are usually blissfully ignorant about is why when submitting files for publication photographers should submit high resolution wide gamut RGB files and let the printer do the conversion to CYMK for printing.

So in a nutshell there's not much discussion of CYMK by photographers in photography forums like this because there is no compelling need for anyone outside of offset printing to use it or really understand it. But as with most things a broader understanding of a subject isn't a bad thing either if you are curious.

May 18, 2013 at 08:48 PM

RustyBug
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p.1 #6 · Why essentially no discussion about CYMK?

Needs based ... CMYK isn't as "needed" for most folks.

When I took my first printing class in 1980's ... the whole CMY think fried my brain, such that I just stuck with shooting chromes and skipped out on it altogether.
Fast forward to digital about three decades later, and several good FM'ers here had to straighten me out on RGB to get things started.
As a student (in recent years) of Dan Margulis' books that others reference, here are a few points that I've synthesized (i.e. my .02 perspective) along the way.

RGB ... Red (0,360), Green (120), Blue (240)
CMYK ... Cyan (180), Magenta (300), Yellow (60), Black
LAB ... Luminance, Green (120) / Magenta (300), Blue (240) / Yellow (60)
NOTE: ... LAB numbers are based on PS Color Checker equivalency, please correct if technically inaccurate.

From Dan's perspective, this represents 10 channels from which to work, and K is one of them ... but after having dedicated some time to learning to work in each, I find that they are all essentially taking the same 360 color circle and dividing them in different ways. As a result, working from RGB (120 degree separation) is the same as working with the reciprocal CMY (120 degree separation) ... just offset by 180 degrees.

So, if you are working in RGB you are basically working in CMY inversely anyway. Notice that many sliders are Cyan/Red, Magenta/Green, Yellow/Blue ... thus, there is little reason to convert to CMY(K) until you have specific needs for working with the K, GCR or ink volume aspect of CMYK vs. RGB, or want to specifically isolate the K channel.

LAB works from the same 360 color circle, but divides the degree of separation into a non- 120 degree trisection, thus differing from the RGB/CMY approach ... and has the luminance channel separate.

In that regard ... for many folks (in practical terms) CMY is only an inverse redundancy to RGB. For myself, if I want to use a Cyan channel, I just use the Red channel followed by Ctrl-I and "voila" I've got the Cyan channel (GCR/K notwithstanding) without ever going to CMYK space.

Dan's point @ 10 channels is pertinent to having multiple ways to slice/dice the 360 degree color wheel ... using whichever slicing paradigm that best suits your ability to isolate things to fit your practical/working needs.

So, to your question @ why not much FM press about CMYK ...
1) most folks don't live in the GCR/K/offset realm
2) those who are well versed in control of RGB, realize that it is simply the inverse of CMY anyway and use it accordingly

Some people will speak to doing some sharpening in the K channel of CMYK that is different from RGB offering, but I usually head for L (Luminance) channel of LAB if I want to go that route. Thus, for me it is mostly RGB (95%), followed by LAB (4.99%) and CMYK (0.01%) ... i.e. CMYK gets very little press, as it gets very little use.

CMYK used to be some magical, mystical thing that only people who really knew color knew CMYK, and I was in awe of it. Now, I just see it as the inverse of RGB (noting that K/GCR/ink volume is a pertinent distinction if needed for output variance) for color correction/pp purposes and printing instructions for those applications that require being told how much black ink to use (i.e. that can't convert from RGB to CMYK or you don't like their conversion process) ... if that makes any sense.

May 19, 2013 at 12:50 PM

Ho1972
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p.1 #7 · Why essentially no discussion about CYMK?

One of the biggest disservices Adobe ever did was bringing out new CMYK profiles with the advent of proper color management in Photoshop -- U.S. Web coated (SWOP) v2, for example -- without enabling them to be modified in the software.

Oh sure, you can load SWOP v2 as your assumed starting point and then generate a custom CMYK in the dialog box, but what you get is not SWOP v2 + the mild dot gain curves tweak you thought you'd made. As soon as you choose "Custom" you revert to Photoshop's legacy conversion which creates something altogether different. Fortunately I didn't make an expensive mistake...

CMYK output may be trickier now than it's ever been, especially for people like me who do it only rarely and don't have anything other than Photoshop for separations. Print shops buy paper and ink based on whatever is cheapest when they make the buy, so the parameters are, now more than ever, a moving target.</rant>

Good thing I don't land any high-end work.

May 19, 2013 at 02:36 PM

nolaguy
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p.1 #8 · Why essentially no discussion about CYMK?

Thank you all for your replies. I don't fully understand it all but am processing. No pun intended.

Chuck

May 19, 2013 at 03:09 PM

mshi
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p.1 #9 · Why essentially no discussion about CYMK?

The whole world has moved to screen. If you don't believe in that, ask Adobe what it has bet the farm on. CMYK sounds superannuated already.

May 19, 2013 at 03:15 PM

Peter Figen
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p.1 #10 · Why essentially no discussion about CYMK?

I dunno. Everywhere I look I see people reading books, magazines, newspapers, brochures, CD covers. Vinyl LPs are making a big comeback as well. CMYK is very very much alive, just not in the sights or capabilities of most photographers. Unfortunately, there's far too much mediocre quality printing going on and far too little people or clients who give a damn enough to spend a few extra dollars on that last little extra to make things pop.

May 19, 2013 at 03:50 PM

RustyBug
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p.1 #11 · Why essentially no discussion about CYMK?

Peter Figen wrote:
Unfortunately, there's far too much mediocre quality printing going on and far too little people or clients who give a damn enough to spend a few extra dollars on that last little extra to make things pop.

+1 @ "good enough" vs. "good" ... i.e. not necessarily the same thing.

Striving to learn to be "good" in world that limits their valuation to "good enough" can be a bit challenging & frustrating at times. Someday, I hope to be "good" ... sometimes wondering if there will be anyone left who actually wants "good", even if I ever do achieve "good". Likely, not so much in my neck of the woods, I'm afraid.

May 19, 2013 at 05:35 PM

river rover
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p.1 #12 · Why essentially no discussion about CYMK?

OK I'm going to rant a bit. I spend at least ten hours a day within various print, web and video applications. I'll freely admit that I'm a generalist but I'm still expected to be fluent in Photoshop, Illustrator, InDesign, Dreamweaver, Final Cut Pro, Premiere, After Effects, Motion, Cinema 4d, and Flash as well as HTML, CSS and Javascript, in addition to making sure that files move smoothly between all these apps with a minimum of quality loss. When I started in the print business I could spec GCR and UCR, Trap Illustrations,convert Spot to process including Duotones out of Photoshop(What a nightmare that is) . The sheer volume of expectations with in the "creative professional" genre has forced me to trust specific professionals at print shops to handle the prepress stuff. DO i cringe every time something comes back from the printer with a slight color shift? Oh yeah, do I say good enough? Yeah. Because somewhere in there there still exists the reason I was hired, the actual creative designing.

OK rant off and thanks for letting me blow off some steam. Now if you'll excuse me I've got to story board a 7 minute dynamic typography animation and convert a couple HTML websites to drupal themes.

Signed,

Wait, I forgot my name.

(Yeah I know, I've got first world problems)

May 19, 2013 at 05:56 PM

river rover
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p.1 #13 · Why essentially no discussion about CYMK?

I'll add one more thing back on subject. Expectation of the general public have radically changed. They expect prints to have the same POP as a screen. Ain't ever gonna happen. Color Gamut shifts are one thing, but expecting reflective media to have the same pop as transmissive color is a recipe for disappointment. It's the equivalent to someone shooting transparencies for the first time and expecting the print to pop like it did on the light table.

May 19, 2013 at 06:28 PM

Peter Figen
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p.1 #14 · Why essentially no discussion about CYMK?

"One of the biggest disservices Adobe ever did was bringing out new CMYK profiles with the advent of proper color management in Photoshop -- U.S. Web coated (SWOP) v2, for example -- without enabling them to be modified in the software."

Overall, that's one of the best things they did. That profile did a better job of describing web offset printing, on average, in the U.S. than the old Custom CMYK ever could. For the most part, and of course, there are exceptions, those separations faired quite well on all sorts of magazine presses around the country. It also didn't hurt that the biggest magazine printer in the country actually got on board with standardizing their press runs and everyone benefitted from that.

"Oh sure, you can load SWOP v2 as your assumed starting point and then generate a custom CMYK in the dialog box, but what you get is not SWOP v2 + the mild dot gain curves tweak you thought you'd made. As soon as you choose "Custom" you revert to Photoshop's legacy conversion which creates something altogether different. Fortunately I didn't make an expensive mistake..."

That was one of the biggest misunderstandings - that the ICC engine and the Custom CMYK engine were somehow related. They weren't other than in later years you could save out your Custom CMYK "profile" as it were, in the ICC profile format.

If you were creative enough, there were ways to alter the characteristics of the SWOPv2 profile, which, in general had a bit too much ink and too heavy a black plate, but you couldn't do it with Adobe software. You could use the free ColorLab app (free and unsupported, but great nevertheless) to basically reverse engineer the measurement data that Adobe left out of their SWOP and Sheetfed profiles, then import those new data sets into ProfileMaker Professional and rebuild the profile using whatever new parameters you needed. Sure, it took a few extra steps with arcane software, but it did work pretty well and got me out of a couple jams. The ProfileMaker Edit Module allowed you to do all sorts of tweaks you could not do anywhere else, including Selective Color and Media White Point alterations. That Edit Module might have been the best piece of software Gretag ever made. It was easy to use and understand but has now been orphaned to older operating systems only with nothing new to replace it from X-Rite.

"CMYK output may be trickier now than it's ever been, especially for people like me who do it only rarely and don't have anything other than Photoshop for separations. Print shops buy paper and ink based on whatever is cheapest when they make the buy, so the parameters are, now more than ever, a moving target."

The only thing that makes CMYK trickier now is that there are so many different standards. Many shops now claim to be GraCol compliant, but many are saying that just because it sounds good. A good print shop can come damned close to their proofing system, and as long as you're not using some weird off the wall paper, there are not too many problems. Usually we profile the proofing system and not the press itself, as the proofer is far more stable and repeatable. Much easier for the press operator to massage the press to match the proof than the other way around.

May 19, 2013 at 06:42 PM

Ho1972
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p.1 #15 · Why essentially no discussion about CYMK?

Overall, that's one of the best things they did. That profile did a better job of describing web offset printing, on average, in the U.S. than the old Custom CMYK ever could.

No argument about the results. I didn't mean to imply that Custom was anywhere close to equivalent (far from it), it's just that I think Adobe should have given some advance warning that the new CMYK ICC profiles were incompatible with the old curve editing functions in PS. I came to that understanding before any real damage was done, but I'm sure others weren't as fortunate.

The only thing that makes CMYK trickier now is that there are so many different standards.

It's a witches brew of variables in my book. Maybe paper stocks and ink aren't the culprits I give them credit for, but it's kind of annoying to rerun a job and be told that the paper you liked so well from a few of months ago is no longer available.

Overall, I've dodged the bullets pretty well for someone who got into doing separations as a by product of graphic design. I guess I've been lucky enough to work with good printers. Any success I've had is more about them making me look good than anything else.

May 19, 2013 at 07:22 PM

Peter Figen
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p.1 #16 · Why essentially no discussion about CYMK?

Adobe did tell everyone about the differences between the ICC engine and the Custom CMYK, but they did a piss-poor job of it and there were too many people who, and people who should've known better, were broadcasting that all you had to do was load your SWOP v2, jump over to Custom CMYK and tweak away. It was way too easy a mistake to make and too many were suckered into it. Personally I never had an issue with having to buy third party apps to do what I needed to do, but more than a few thought that Adobe should build everything into Photoshop for every purpose.

May 19, 2013 at 07:30 PM


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