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Getting depth in cmyk conversions

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  #11  
Old 11-04-2015, 05:09 PM
Shoku Shoku is offline
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Re: Getting depth in cmyk conversions

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Originally Posted by andrewrodney View Post
Keep in mind that you simply can't reproduce some colors so attempt to maintain the color relationships you see visually. ICC profiles, any automatic process simply can't do this. We humans have to view pixels in context and make intelligent and artistic decisions.

NEVER show the client the RGB data! Always show them the soft proof in CMYK.
I agree with this one hundred percent. We get lots of out of gamut RGB files and the best way to deal with them is to adjust while still in RGB to reduce saturation in the problem areas, then convert, and then adjust again as needed.
Doing this will help maintain detail that otherwise would be lost.

Some clients have difficulty understanding these limitations because they work only in RGB.
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  #12  
Old 11-04-2015, 05:14 PM
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andrewrodney andrewrodney is offline
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Re: Getting depth in cmyk conversions

There's an old saying: God (I prefer Dog) created RGB, man created CMYK, which would you rather use?
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  #13  
Old 11-04-2015, 05:17 PM
klev klev is offline
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Re: Getting depth in cmyk conversions

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Originally Posted by rl-retouch View Post
Great, it's just disheartening when cmyk destroys so much after all the hard work
It doesn't necessarily do so. If it's going to be shown online anywhere, they could still use that. For print it usually looks better to err on the side of preserving detail. It's not as big of a deal as it seems. Some of the camera profiles are much wider than Adobe 1998, yet none of them are an easy fit into a workflow involving photoshop.
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  #14  
Old 11-04-2015, 09:02 PM
klev klev is offline
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Re: Getting depth in cmyk conversions

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Originally Posted by andrewrodney View Post
So you're seeing this on the proof or just on-screen? You know this is the specific profile to be using?

Be useful to post a small low rez RGB version (300x300 pixels) which I could load into ColorThink and examine the actual gamut of the image itself compared to the profile. But look, the gamut is what it is, you can't do anything about it. OOG colors will clip or render based on the profile and the RI you use, you really don't need to be overly concerned with clipping per se but rather, soft proof to the CMYK profile while still in RGB! See if in the larger gamut space there's any selective color tweaks you can apply to those areas you mention. Keep in mind that you simply can't reproduce some colors so attempt to maintain the color relationships you see visually. ICC profiles, any automatic process simply can't do this. We humans have to view pixels in context and make intelligent and artistic decisions.

NEVER show the client the RGB data! Always show them the soft proof in CMYK.
Okay now I'm really confused. I said to tweak it before converting and you became angry. As I mentioned you should favor detail. I think hue/saturation or channel mixer combined with a mask are appropriate for something product oriented. I'll also mention that matrix based profiles don't really have lookup tables in the same sense. They're defined by basis changes from rgb to and from some pcs (typically LAB), so rgb->lab->cmyk. Lookup tables work differently. After reading this I'm not sure why you were angry before. I referred to photoshop for most of it, but perceptual is still a really bad mode. They tried to fix it with v4 profile specifications because of that.
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  #15  
Old 11-04-2015, 09:51 PM
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andrewrodney andrewrodney is offline
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Re: Getting depth in cmyk conversions

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Originally Posted by klev View Post
Okay now I'm really confused.
I so agree!
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I said to tweak it before converting and you became angry.
I didn't get angry, I called you out for some ridiculous text about perceptual rendering of ALL ICC profiles.
It's rather clear you're not paying attention to the text! IF you were, you'd see that the first post made after the OP (by ME) stated:
Quote:
Open the original and soft proof with the CMYK profile, edit on layers on the RGB data and see if edits prior to CMYK will help.
Yet you think I'm angry because you said what I already did before you arrived? Really?
Quote:
As I mentioned you should favor detail.
You should when that's an important aspect of the image! And further, as I attempted to point out to you, that decision must be conducted by a human with some taste and ability to view the image in context and make such decisions, NOT dismissing a profile table.
Quote:
I'll also mention that matrix based profiles don't really have lookup tables in the same sense.
So what?
Quote:
They're defined by basis changes from rgb to and from some pcs (typically LAB), so rgb->lab->cmyk. Lookup tables work differently. After reading this I'm not sure why you were angry before
So people who don't agree with you, people who ask you to prove your points (about how the ICC didn't get perceptual right from day one; nonsense), that's what you call angry? Maybe English is a 2nd language and if so, I'll cut you more slack.
Quote:
I referred to photoshop for most of it, but perceptual is still a really bad mode.
So we should take you as a perceptual table bigot? Because you've provided zero proof or evidence of what you keep saying, despite the facts of the color science I've provided that easily dismisses this bigotry.
Quote:
They tried to fix it with v4 profile specifications because of that.
Who is 'they'? Not Adobe, they have very little to do with how the ICC org as a group spec's V4 functionality, there's absolutely nothing to gain from V4 profiles as there isn't a single product I'm aware of that even supports the PRMG (the 'big deal' about V4 anyway).

Your concept that everyone should never use a Perceptual rendering has no merit. I'm not angry, I'm disappointed that you can't back up any of your claims and don't seem to be following the text well. Sorry.
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  #16  
Old 11-07-2015, 10:26 PM
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Benny Profane Benny Profane is offline
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Re: Getting depth in cmyk conversions

Good lord. Have you been to the dentist's office and handled and looked still a magazine printed in 2015? The stuff is printed on material you would use as an alternative to something else in your vacation cabin. That's your problem. It ain't midpoint black compensation, blah, blah. Try all you may, but print is dying.
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  #17  
Old 11-08-2015, 08:41 AM
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andrewrodney andrewrodney is offline
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Re: Getting depth in cmyk conversions

The resident troll returns with words without wisdom or an attempt to aid the OP, hiding behind an aliases to provide immunity to his lack of chops, (experience) or the fact he sneaked again into his daddy's office and once again got control of the keyboard.

Doug, do we really need this again?

Last edited by andrewrodney; 11-08-2015 at 08:55 AM.
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  #18  
Old 11-11-2015, 11:35 PM
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Benny Profane Benny Profane is offline
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Re: Getting depth in cmyk conversions

Shouldn't it be "Daddy, Benny is being a jerk again! Sniffle. Make him shut up and stop. Sniffle"
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  #19  
Old 02-14-2016, 02:17 PM
zackahern zackahern is offline
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Re: Getting depth in cmyk conversions

Personally, and it may be incorrect, I would convert to CMYK and then try to match it to the RGB version with curves. It's the only way you're going to get your colors as close as possible. It's not going to come from a perfect conversion because you're always going to have shifts, especially in saturated colors. Pick your battles! Convert a CMYK version and adjust it to match the RGB rather than trying to make RGB adjustments and then predict what that's going to do in CMYK.
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  #20  
Old 02-14-2016, 02:23 PM
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andrewrodney andrewrodney is offline
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Re: Getting depth in cmyk conversions

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Originally Posted by zackahern View Post
Personally, and it may be incorrect, I would convert to CMYK and then try to match it to the RGB version with curves. It's the only way you're going to get your colors as close as possible. It's not going to come from a perfect conversion because you're always going to have shifts, especially in saturated colors. Pick your battles! Convert a CMYK version and adjust it to match the RGB rather than trying to make RGB adjustments and then predict what that's going to do in CMYK.
The main issue here is, while you can attempt to make the two appear the same, you're not taking into account a huge can of worms, namely black generation, GCR/UCR. IOW, you can have half a dozen CMYK files that visually appear the same, on-screen to each other and/or an RGB document with vastly different black gen which WILL affect the actual output!
For example: color appearance IN Photoshop looks the same, Black Gen, vastly different:
digitaldog.net/files/BlackGenCMYK_Skin.jpg
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