re: Color shift in PhotoShop 8
re: Color shift in PhotoShop 8
- Subject: re: Color shift in PhotoShop 8
- From: Steve Upton <email@hidden>
- Date: Fri, 22 Jul 2005 10:15:55 -0700
At 7:56 AM -0700 7/22/05, Rick Stubblefield wrote:
>First, let me say thank you to the responses so far. But, secondly, I now
>feel that after years of doing this (pre-press), studying Real World Color
>Management, taking various seminars and following this list daily as well as
>using the color and PhotoShop forums at Adobe this morning I now understand
>less today than I did yesterday.
it does get that way I'm afraid. But hang in there, in the world of color management it really does mean you are learning...
>The workflow I have relied upon the last few years came about because of
>things I learned from someone, who knows far more about this than I do. His
>point was that "assigning" a profile is not enough (at least in the
>pre-press world) that a file in question must be "converted" to a color
>space; that by the very nature of imaging to film or plates takes one out of
>a device independent world and puts one square in the middle of a device
>dependent world.
I don't disagree with that. Assigning a profile to a file sets it up for proper future conversions but it doesn't change the CMYK values in the file so conversions are still required. (assuming the CMYK in the file is not the right one to go to press)
>Makes sense to me. But Steve Upton writes:
>
>>this is the one that makes me say whoa! Convert TO the embedded profile?
>
>>I don't even think this is possible, not that you'd want to do it.
>
>>You CAN convert to the std CMYK workingspace profile, also rather
>>heavy-handed...
>
>So, if I can't convert to an embedded profile but I can convert to my
>working space profile I am not sure where this leaves me
Well normally you would not need to convert TO an embedded profile. The file's CMYK values are supposed to be - by definition - IN the embedded profile's flavor of CMYK. The profile is coming along for the ride to explain to the world which flavor of CMYK is in the file.
>(not even debating
>the heavy-handed bit at the moment).
that's mostly just about the idea of converting each and every file you get. If your printing situation is such that all the CMYK you receive is inappropriate (like SWOP CMYK is to a T-shirt printer) then it makes sense, otherwise it seems, well, heavy-handed. Truth is that if it works for you, cool. I hope that the implications are understood though. So when all incoming K--only blacks become 4 color blacks that's OK and expected with you and your clients.
>If I understand what you are saying,
>the only profile I can convert to is my working-space profile. Correct?
no and yes. You can convert to any profile you want in the "Convert to Profile" dialog or if you choose a different one when opening but if you want to streamline it so the conversions happen automatically when you open then yes.
>
>Moving on, C. David Tobie writes:
>
>>You can't open a file that you have clipped the tag from in Photoshop and then
>>apply another profile and get reasonable consistant results. Photoshop has to
>>assume some colorspace for untagged files, and so is opening the file in the
>>default CMYK colorspace, which, if it differs from the space you actually had
>>the file in before removing the tag, causes incorrect colors... such as a
>>yellow cast.
>
>So, does this mean that when PhotoShop gives me the choice, upon opening a
>file, to use the embedded profile, assign a different profile or not to
>color manage that the phrase "don't color manage" is actually incorrect?
>That it is not truly not color managing but using whatever defaults I have
>chosen in PhotoShop?
bing! You've got it. "Don't color manage" is a euphemism that allows non-color management-savvy prepress people to feel comfortable using any version of Photoshop later than 4.x. It is also a workflow that avoids converting CMYK when people don't expect it. When you think about it though the only way CMYK can be viewed on screen is after a color management conversion to RGB and if you want to convert the CMYK to a different flavor of CMYK, CM is used as well. In both of these cases a source profile is required and Photoshop's CMYK working space profile is used.
>Okay, now that I am even more confused and have asked even more questions
>where does that leave me?
further down the path of enlightenment....
> I read into all this that the incorrect thing I
>have been doing (as an aside, up until this one particular file I have never
>experienced a color shift like this before) is converting to the embedded
>profile when I should be converting to my press profile? And Steve, if this
>is "heavy handed" what would my alternative be? My understanding has always
>been that if I only assign a profile I haven't actually changed the file to,
>in effect be, device dependent; i.e. my image setter.
Your original workflow description confuses me a bit. Can you walk us through the path the file would take, including dialog boxes & choices? This would help a lot.
>All I really want to have happen is to be able to have what I see on the
>screen, my high res proof and the final printed piece all look reasonably
>similar; and until this one file that was happening for me consistently.
yeah, it's a reasonable desire. One we all share. One that can be achieved.
>I am not above changing my habits (and it looks like, once again, I do need
>to change my habits) as I never, certainly don't consider myself to be an
>expert in color management. I have seen in this forum that even the experts
>sometimes need to look for answers from other experts.
oh yeah, indeed. This forum is one of the best of any type anywhere.
Regards,
Steve
________________________________________________________________________
o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX
o email@hidden 206.985.6837
o ColorGear ColorThink ColorValet ColorSmarts ProfileCentral
________________________________________________________________________
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