How to avoid Rich Black in RGB Mode/CMYK Breakdowns going Nuts

C
Posted By
ColorBomb
Jan 9, 2007
Views
872
Replies
12
Status
Closed
Working in PS CS2 (9.0.2)/mac.
Is there a way to define 100% black in PS while in layered RGB mode without the breakdowns jumping back to a "rich black" status? Example…make a line of text in PS, then go to the color picker and type in (cmyk values) 0-0-0-100. Now go back & highlight the text again and check the color…it changes back to a rich black of 73-63-61-100! (Note, the actual rich black breakdowns you get may vary depending on what "color settings" you’ve picked. I’ve experimented with about all of the color settings and I get a different breakdown each time but can’t get my black to stay 100% non-rich black.) This doesn’t seem to be a text issue; I get the same problem coloring a box from any location in PS.

Gets weirder…The above tests were using "adobe color picker" in the PS preferences. If I change my picker to "apple" I don’t get varied rich-black breakdowns using different color settings, but it’ll still revert to 100-100-100-0/rich black (even though I typed in 0-0-0-100). So basically no matter what color picker I use, or where I define my color, I can’t get a 100% black (with no other colors involved) to stick.

Now get this…I have a cmyk breakdown color I need to use in PS. Back in good ‘ole PS 5.5 all I had to do was click on a layer and define the color as my cmyk I wanted. Now in PS CS2, my cmyk breakdowns I type in don’t "hold". Example, in RGB mode, if I type in 0-cyan 100-magenta 50-yellow 0-black and then fill a box, the cmyk breakdown in the Info pallet changes! Granted, it’s not a "big" change. It seems to depend on what color settings I’m using as to how far off the colors go. But to me PS tossing 3 percent into the Cyan negative/channel and 2% into my Black channel is only making my nice pink look muddy. *This is only a problem when working in RGB mode. If I put in cmyk color breakdowns in CMYK mode, they hold just fine. (Some might not understand the reasoning for working in an RGB mode and then later converting to CMYK and I won’t go into all that; just know it’s important I do it that way and it’s also important that my cmky breakdowns be correct when I type them in.)

Sorry for the long question. I just can’t believe I spent all this money upgrading and I feel like the program was actually better the way it was years ago. I would greatly appreciate anyone who could help me out here. I called "tech-support" and they had no idea; said they’d "call me back if they figured it out." G-thanks

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PT
Phil_Taz
Jan 9, 2007
Hi Colorbomb….

welcome to colour management. Don’t make the common mistake of thinking that colour man’ is some geeky irrelevant topic to be avoided like most people do at first, if you can get your head around it you will be glad in the future.

You can’t have a C0,M0,Y0,K100 in rgb, it doesnt exist, it is like trying to unmake a cake.

There are colours in rgb that dont exist in cmyk, which is the usual reason that colours look muddy…I understand you wanting to work in rgb, I do it all the time and I can control what cmyk values I get out and I can understand what colours can and cannot be created this way.

Take a deep breath and read up on colour management and conversion, the changes you see sound like normal colour management doing its ‘thing’.

Here is a site with some basic info that may help to clarify things. www.goannaprint.com.au
there is a link at the bottom of the page to colour management explanation.

Hope that helps.
PF
Peter_Figen
Jan 9, 2007
This isn’t really a color management problem. It’s more a problem of not understanding both how Photoshop’s color engines are structured and not understanding black generation.

You CAN get your blacks to go to 100% K by using a color separation setting that uses Max black generation, but it will probably screw up everything else in your image. Whenever you spec a CMYK mix while working in RGB, PS can only use the current separation setup to compute the numbers for the info palette. Even with a Max K black gen, you still may need to nudge the mix a bit in Selective Color. The ideal situation for you is to make two separations, one for the black that you want to keep at 100 K and another optimized for the rest of the image, combining the two to create your ultimate file, but don’t expect it to materialize magically from a single RGB file.
AR
alan_ruta
Jan 9, 2007
Actually what Peter is explaining is alwo a very nice tool for checking what the separation values in CMYK (while eyedropping in an RGB file) will be depending on how you set up the black generation/UCR/UCA.

alan
C
ColorBomb
Jan 9, 2007
Oh my, I think I’ve opened up a can of worms here.
Bless you both for responding. I think maybe I should have been more precise as to why this is a problem for me.

-I get files from clients where they have laid out entire brochures in PS. Most of the time they’ve used tiny black text that is set to be a rich-black. My goal would be to try and trick PS into only putting that black text on the black plate. Now it seems I can’t do that.

It seems I have 2 problems in PS CS2…the program always reverts to a rich black (no matter what I type in) and the cmyk breakdowns I type in (in RGB mode) decide on the fly to change into another cmyk breakdown depending on the color settings I have selected.

Do this test & see what you get: Open PS, make a new doc in RGB mode, fill the background with 50% yellow. Now type a bit of black text, color the black text 0-0-0-100. Now get your eyedropper tool or look over in the info window and see what happens. PS not only changed my 0-0-0-100 black text into a cmyk-rich black, but it also made my nice 50% yellow into a 1-2-50-0 yellow. Problem arises if I place this image into Indesign on top of a 50% yellow background, it won’t match. I would have to make the background in ID match the muddy 1-2-50-0 yellow. (Yes, I know…I wouldn’t put an RGB file into ID, I would convert it to CMYK first, but that doesn’t help this scenario.) Since this is black text on a light yellow background, my goal would be to have the black text "overprint" the yellow, but of course only on the yellow plate (no need to also have the black on the cyan & magenta plates). In theory, I should be able to highlight the black text and color it with 50% yellow and 100%, therefore tricking the black text into an overprint on the negatives. Now that’s impossible since PS refuses to allow me to pick my own "rich black" cmyk breakdown in RGB mode. (Yes, in a perfect world the text would be in ID anyway, just humor me, remembering most files I receive clients have tried to do everything in PS.)

So it’s not only the forced rich-black that concerns me, it’s the fact that in RGB mode you can’t seem to type in a cmyk breakdown without PS converting it on the fly to some other set of numbers. My cmyk numbers only seem to "hold" if I’m in "cmyk" mode. I don’t want to do my layered files in cmyk mode since that ignores the entire reasoning behind have different printer color settings defined (so that the density/ucr/gcr/etc) behaves correctly during an rgb to cmyk conversion.

(Note, what I’m describing would also be a problem if a client sent in an RGB file with black text on a white background with some colored elements elsewhere on the page. You would only want the black text to be on the black plate, but now in PS the black text is going to show up on all the plates. Again, I know PS isn’t the best place to have this black text in the first place, we’re talking about clients who’ve already set up the entire job this way.)

Thanks again…let’s give this a roll and see who wins the cookie. Bueller? Bueller?
B
Buko
Jan 9, 2007
After you convert to CMYK select the text and make it 100% K
PH
Paul_Hokanson
Jan 9, 2007
I get files from clients where they have laid out entire brochures in PS. Most of the time they’ve used tiny black text that is set to be a rich-black. My goal would be to try and trick PS into only putting that black text on the black plate. Now it seems I can’t do that.

Educating your clients to cease this practice would be a helpful first step. If they’ve supplied a layered PSD, then do as Buko suggests. If you only have a flattened RGB to work with, then it may not be possible to get all the small text on the black plate only.
MO
Mike_Ornellas
Jan 9, 2007
Educating clients is futile.
PF
Peter_Figen
Jan 9, 2007
" Now type a bit of black text, color the black text 0-0-0-100. Now get your eyedropper tool or look over in the info window and see what happens. PS not only changed my 0-0-0-100 black text into a cmyk-rich black, but it also made my nice 50% yellow into a 1-2-50-0 yellow. Problem arises if I place this image into Indesign on top of a 50% yellow background, it won’t match. I would have to make the background in ID match the muddy 1-2-50-0 yellow. (Yes, I know…I wouldn’t put an RGB file into ID, I would convert it to CMYK first, but that doesn’t help this scenario.) Since this is black text on a light yellow background, my goal would be to have the black text "overprint" the yellow, but of course only on the yellow plate (no need to also have the black on the cyan & magenta plates). In theory, I should be able to highlight the black text and color it with 50% yellow and 100%, therefore tricking the black text into an overprint on the negatives. Now that’s impossible since PS refuses to allow me to pick my own "rich black" cmyk breakdown in RGB mode."

I tried your scenario after changing my CMYK Setup to Custom CMYK – Maximum Black, and while the yellow did contaminate, the black type, even after rasterizing, flattening and converting to CMYK, remained 0,0,0,100, exactly as you would have wanted. A quick nudge in Selective color would take care of the yellow and you’d be done.

Your real problem is that you need to educate your clients as to how to properly prepare files, inlcuding which appllications are better for their and your purposes. Ultimately, no one should be setting fine type destined for offset, in Photoshop.
PT
Phil_Taz
Jan 9, 2007
You need to recognise the difference between the principles of CMYK/RGB printing compared to your real intention.

CMYK process is a method of specifying screen/ink values in patterns that give an acceptable, predictable image on paper it does not care about matching original hues or sharp text.

RGB is for specifying satisfactory colouring of pixels with no regard for sharpness, matching original hues etc.

What Colorbomb is trying to achieve is clear, but the method is wrong.

To use a cake analogy, CB is taking all the chemicals that make up milk, eggs, flour and raisins and expecting to get a tasty teacake, in theory it sounds good but in practice it does not work.

If you want a specific black in cmyk then make it in cmyk, if you want to make images in rgb, that is fine, but don’t expect the cmyk to be a perfect cake. All your colour conversions must be done through an asymmetrical interpretation so, like the cake, you have the ingredients but not the process. You need to understand how your plan is not working and you will find a way to do what you want….
MO
Mike_Ornellas
Jan 10, 2007
There is a RGB-K workflow, but your brains may pour out of your ears…
C
ColorBomb
Jan 10, 2007
Thanks so much to everyone for your help. Your tips/work-around have helped. I suppose I was hoping that somewhere in the PS CS2 preferences I had overlooked some sort of option (like "don’t mess with my cmyk breakdowns if I tell you to make them as such" or maybe "please allow me to make something the exact color I wish it to be.") LOL

Phil: You’re cracking me up. I know how to bake a cmyk cake, the problem is not many of my clients do. I’ve been doing this for 15 years now (10 of which in a prepress environment), so I’m on board with all you’re saying. Although, I pity someone who is just starting out and needs some helpful advice as opposed to a sermon. Is it ok that I called your advice a sermon? It’s only fair…you compared my PS methods to baking. LOL (please find humor in this…life is short!)
My real intention is to compose a successful PS RGB document, correctly using my color management settings while still having the ability to look far enough ahead in the prepress process to realize when my CMYK conversion occurs I may need to tweak some things for a better (less muddy) output. In essence, PS developers have tried to make PS "idiot-proof" and have therefore thrown a monkey wrench in my personal workflow dealing with clients who may not understand the reason why it’s not good to do "everything" in PS. amen

Thanks again everyone & happy posting!
PT
Phil_Taz
Jan 10, 2007
CB, I am writing like a sermon because I am addressing you AND the others reading this thread….no offence taken!

But you are missing the point, you are trying to get an egg out of a cake by using rgb values to drive cmyk…of course it is possible, but my assertion is that it is not a good workflow.

Colour these days is (generally speaking) a concept in LAB which is interpreted into rgb or cmyk or whatever, and any translation between those colour spaces is through a conversion, managed by a CMM. These conversion are asymmetrical, so you can’t just pass them back and forth without harm.

And…aiming for a particular cmyk mix is not a valid task in colour managed workflow. cmyk is a symptom, like the cake.

Nothing wrong with putting RGB (or greyscale) into your ID layout either, if you do the CM correctly.

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