CMYK file_EPS file setting_question

[studio347]

Hi,
I want to ask a question to printing professionals.
I need to prepare CMYK EPS file for a client.
I'm working my files as prophoto color profile at 16 bit in photoshop.
What's the best way to convert to CMYK_EPS file in photoshop?

I got an advice below_
~change the RGB tiff file to Lab color first then~ changing to CMYK tiff file.
Is this a right way to do it?
And ~ save as photoshop EPS file.
When saving to EPS file, what's the right selection to choose?
ASCII85 or JPEG Maximum?
What's the right way? I noticed that the ASCII selection makes about 4 times bigger file size but it has very very little more highlight and shadow details.
What's the real meaning for these in printing?
Many thanks in advance!!

[digitaldog]

You're getting some bad advise (the Lab part). Danger Will Robinson, DANGER!

First things first. Do you have the specific and exact output profile that will be used for the CMYK conversions? Not something built into Photoshop. If not, you don't even want to think about this task!

http://www.ppmag.com/reviews/200703_rodneycm.pdf

http://digitaldog.net/files/CMYKPart2.pdf

[studio347]

thanks for the infos.
I can use the US web coated (swap)v2. Or at least, let's assume it's correct for now.
My question is is there benefit to this GRB>Lab Color>CMYK conversion method?
I mean the conversion to Lab color without any adjustment. The person who advised this, implied that this 2 way process might produce best RGB to CMYK conversion. Is there any reason for this advice if this is a correct advice?

For the EPS, the JPEG maximum setting is any practical weakness compared with ASCII85 setting in real printing world?

[digitaldog]

I can use the US web coated (swap)v2. Or at least, let's assume it's correct for now.

That's a hugely dangerous assumption but whatever.

My question is is there benefit to this GRB>Lab Color>CMYK conversion method?

Unnecessary, time consuming, damaging.

Is there any reason for this advice if this is a correct advice?

No.

[Schewe]

My question is is there benefit to this GRB>Lab Color>CMYK conversion method?
I mean the conversion to Lab color without any adjustment. The person who advised this, implied that this 2 way process might produce best RGB to CMYK conversion. Is there any reason for this advice if this is a correct advice?

Totally bogus and backwards...first off, transforming from ProPhoto RGB to Lab is silly because both are large gamut color spaces with different gamuts and gamut shapes, so your image data will face a useless color transform for no good reason. The ONLY reason to go to Lab is if you needed some severe color corrections that you can't do with RGB. But this will be very unlikely to be the case.

You will get a better color transform going from ProPhoto RGB > CMYK after soft proofing and optimizing for CMYK. I've been doing separations like this for over 12 years...and I do all the separations for my own printed books this way and the color repro is excellent (given the limitations of the CMYK gamut).

But...the are CMYK profiles and there are CMYK profiles–and they are all over the map. If you are talking about web press for run of book magazine repro, yes, the US Web  Coated SWOP is a likely reasonable profile, but you won't know that without testing. If you are talking sheet fed, all bets are off because sheetfed presses are usually highly tweaked by the printer company.

Your client needs to give you more info like who and how the images will be printed...for example, do you even know if the printing will be done in the USA? If not, then that's another whole can of worms...

[pfigen]

In addition to what Andrew and Jeff have said, I would ask why they need EPS. I've been working with CMYK files for twenty years now. In the old days, service bureaus would default to EPS because that's what they always used, but for at least the last fifteen years all we've used are tiffs.

[Chris_Brown]

In the old days, service bureaus would default to EPS because that's what they always used, but for at least the last fifteen years all we've used are tiffs.

In my experience, EPS files were requested because the color separation films were output on a Linotronic imagesetter, which used an on-board hardware PostScript RIP. The EPS files provided slightly faster, more reliable output. But this was in 1992. I doubt this is the case now. 

To the OP, read this document, and convert directly RGB -> CMYK, then proof the files with the printer. Prepare for a few iterations of color/tone adjustments & proofing.

[studio347]

thanks for all~
I'm preparing files for a magazine in an asian country first time. I has provided Adobe RGB tiff files all the time without any issues to US clients...
As situation is this, I'm following advices from a photography studio which has been dealing with the client for more than 10 years.
Since I don't understand many issues regarding CMYK file, I wanted to understand from this forum~
I need to ask a few questions to the client and read some more articles...
Many thanks!

[digitaldog]

As situation is this, I'm following advices from a photography studio which has been dealing with the client for more than 10 years.

Well he/she's been doing this in a creazy-ass way for 10 years, no reason to follow,

[studio347]

So~ I have asked a few questions to the magazine art department.
What they want is CMYK EPS file( jpeg maximum engaged..).
I asked the proper color profile for the cmyk file and they have no clue.
(I can't go further since I have tried their patience all the way already with these questions. If I complain with more questions, they feel I'm very weird~ha~and a kind of stupid~)
(Don't be so surprised. I have been in photo school for 6 years and I couldn't understand the concept of color profile in school. I got it after....In some culture, it might be too much... for the all the art department people to fully understand this issue... imagine that you are trying to make your wife to understand this profile thing. They are nice people... just they are not up to it~. I got the similar feeling in dealing with this issue..)
From what I learned, I need to use US web coated v2 as the profile. This is what the photographers are using...

I think some people might think this whole situation is so absurd. But imagine this situation and try to understand the different culture.

Now, my question is what I need to be careful about...in this.. situation other than studying about cmyk and printing in some ways.
My understanding is this.
Photographers are providing CMYK EPS file(w/ JPEG maximum setting) and rough match prints(indicating the intended color and brightness_contrast), and the printer is trying hard to make similar color and tones with the file and match_prints. I think they are trying hard to work with the material and adapting...with the provided materials...
Any advice would be great~ha
In some situation, logic is not always most...important. They are trying to keep the business with limitations and different situation and culture~

[digitaldog]

I asked the proper color profile for the cmyk file and they have no clue.
From what I learned, I need to use US web coated v2 as the profile.

You learned that from the same clueless people?

Any advice would be great~ha

Send them tagged RGB (like sRGB or better, ColorMatch RGB).
OR
Send them a CMYK file with a legally binding contract that holds you free from any color issues that happen on press.
Anything else and you're potentially in a world of hurt.

[studio347]

thanks for good advices.
I had the impression that the whole magazine people have no understanding in color profile... even though they have the desire and understanding for the importance of right color and tones in some ways...
For the us web coated v2, that's what the photographers are using in this area and they are getting pretty close color and tones in the final magazine printing...
My rough guess is that the whole printing factories in this country are adapting to this situations in some ways.... working with the cmyk eps files(w/ us web coated v2 profile) and making the whole business~ editorial business in this asian country. The AD world is ... not sure...

For the tagged RGB, they don't want the RGB files other than sRGB jpegs for preview only. You can imagine that they asked the cmyk eps files to a photographer.... if the photographer provides tagged RGB files in addition to the cmyk files, they will feel that it is not right~ha. If the photographer ask any contract paper signed, I can easily guess that the photographer will not get any more jobs~. If a person cross an important line, the person is out. It doesn't matter if it is logical or not~
It is very interesting that our discussion is mixing with the very technical and scientific issues and culture and social issues~

Like we are all young and trying~ crazy driving or drinking competitions among peers, a very logical person might inform the situation to their parents ~
And the logical person is out...of course. He or she doesn't get it... there is more than logic....
For one, there is DESIRE which is sometimes more important than logic..

[Chris_Brown]

So~ I have asked a few questions to the magazine art department.
What they want is CMYK EPS file( jpeg maximum engaged..).
I asked the proper color profile for the cmyk file and they have no clue.
(I can't go further since I have tried their patience all the way already with these questions. . . )

ugh. What jerks.

I've come across clients & printers who don't want ICC tagged CMYK files, but in those cases it's because they have a prepress department that they want to run everything through in order to maintain an income stream. When I encountered that situation (maybe ten years ago or more), I contacted the dept. manager and I would pay for rounds of proofing. I would get my CMYK proofs (first using a Kodak DCP 9000, then later using proofing paper and an Epson 9600 or Canon iPF printer) to match theirs using an ancient Photoshop technique developed by Kodak for their dye-sub proofers. It worked very well.

The first prepress departments I encountered with this routine were surprised a photographer was taking the trouble to get accurate reproduction. Later they were blown away that a $4000 inkjet printer could make such accurate proofs (compared to their $250,000 Agfa/Dupont/etc digital proofer).

You probably don't have time, but I'd get proofs of your images from the magazine's prepress department and make necessary changes to the files before submitting them. I would also submit the image files with the hardcopy CMYK proofs.

[nemophoto]

I guess the real question for me is, why are you even doing an CMYK EPS? I've been doing pre-press for about 15-years (and always feel I have more room to learn), but haven't had to use EPS files for easily a decade (other than when using certain types of line art, and duo-, tri-, and quad-tones. Even those can be saved these days as PSD files when using InDesign). It seems these guys are 1) clueless, and 2) have no idea what they are really doing, so are just spouting some nonsense that someone may have mentioned in passing, many moons ago. Jeff (Schewe) and Andrew (Digital Dog) have given you good advise. There are still a lot of printers, magazines, art departments and other clients out there who have never really stayed current. Or simply prefer not to know the technical. I can't even begin to tell you the number of AD's I work with who have absolutely no real idea what they're doing, so I'm not surprised by the request.

[ripgriffith]

imagine that you are trying to make your wife to understand this profile thing.

This is an outrageously stupid and sexist comment.

[papa v2.0]

Hi
going from RGB to CMYK using ICC profiles will convert the RGB to CIEXYZ to CIELAB then to CMYK anyway. CIELAB is the profile connection space. So RGB to CIELAB to CMYK is not wrong as such and wont do any 'damage', just an extra step.

in my thirty years in colour reproduction, I have seen many changes.
Now I use tiff or psd file in indesign and then export to pdf using icc profiles.

If , as is the case here in the UK, many printers still are years behind in colour theory and have little real understanding of whats going on and can't or wont (as the don't have the skill to profile a press) send you a press profile, then I use a Fogra Standard eg Fogra39 for sheetfed litho.

I have found out (after a lot of digging and phone calls) that a major trade printer with a massive turnover uses standard profiles from Fogra or ECI.  One would think that they might have had their presses profiled but hey.

If you can get a profile great but if not plump for a safe standard and pull the curves back a bit.

in the days of drum scanners and film planing, it was deemed to produce separations that erred on the light side rather that heavy side, if didnt know who was printing the job.

Iain

[Chris_Brown]

If , as is the case here in the UK, many printers still are years behind in colour theory and have little real understanding of whats going on and can't or wont (as the don't have the skill to profile a press) send you a press profile . . .

Same here across the pond. When I spoke with a prepress project manager about it this summer, he said that the color from clients can't be trusted. They typically accept hi-rez PDFs and it's not unusual to find embedded profiles ranging from sRGB & Adobe RGB to a potpourri of CMYK tags. Sometimes they receive entire documents that are not tagged with any profile.

Instead of educating their clients or putting strict prepress guidelines in place, they simply proof everything and make corrections (and reap the income from that) until the client is happy. This assures everyone involved of the best reproduction possible, even if it takes longer and costs more.

He said they've been doing this since the dawn of "ColorSync" (he even mimicked the quotes with his fingers) because they'd been badly burned in the past.

[digitaldog]

Instead of educating their clients or putting strict prepress guidelines in place, they simply proof everything and make corrections (and reap the income from that) until the client is happy. This assures everyone involved of the best reproduction possible, even if it takes longer and costs more.
He said they've been doing this since the dawn of "ColorSync" (he even mimicked the quotes with his fingers) because they'd been badly burned in the past.

Which is why it's just better to send them tagged RGB, sRGB or a bit better ColorMatch RGB and be done with it. Trying to do anything more complex in terms of handing them any flavor of CMYK is akin to giving a small child a razor blade and allowing them to play with it on the highway!