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Author Topic: Just when I thought it was safe: CYMK?  (Read 2791 times)
walter.sk
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« on: February 24, 2009, 05:22:44 PM »
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Most of the bruises acquired in the fight to learn color management for my RGB images, monitor, printer, softproofing, etc, have begun to heal.  All of a sudden, I need to submit some images on a CD, with possible printing in a photography magazine that prints high quality on glossy (slick?) paper.  The images need to be CYMK rather than RGB.

Am I correct in assuming the process would be similar to softproofing for my printer, as follows:

1)  Bring up an image in RGB.
2)  Set up a custom color proofing dialogue with the CYMK Swop 2 profile, without Simulate PaperColor or Simulate Black Point checked, but with BPC on?
3)  Duplicate the original image, then try to tweak the softproofed one to look as much like the original as possible.

Or:
1) bring up an image in RGB.
2) duplicate the image and convert it to CYMK
3) Tweak it to look as close to the RGB as possible, and then save it with the tweaked layers flattened?

Will I be able to see out of gamut colors in either of these setups?  Or am I grossly oversimplifying the process, and need to start from the zero point on the learning curve?
« Last Edit: February 24, 2009, 05:31:11 PM by walter.sk » Logged
Damo77
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« Reply #1 on: February 24, 2009, 06:11:57 PM »
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Well, first things first, have you confirmed that the CYMK Swop 2 profile is the correct one?

I think you're over-engineering this.  Yes, the out-of-gamut issues with CMYK are perhaps more severe than you're used to, but I don't think you need to approach them any differently.  Which method would you use for a large-RGB-to-small-RGB conversion?

If anything, a CMYK conversion is somewhat easier, because you have Perceptual rendering intent available to you, whereas (from what I've read) you don't have that when converting down to sRGB, for example.
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« Reply #2 on: February 24, 2009, 06:39:50 PM »
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Quote from: walter.sk
Most of the bruises acquired in the fight to learn color management for my RGB images, monitor, printer, softproofing, etc, have begun to heal.  All of a sudden, I need to submit some images on a CD, with possible printing in a photography magazine that prints high quality on glossy (slick?) paper.  The images need to be CYMK rather than RGB.

Am I correct in assuming the process would be similar to softproofing for my printer, as follows:

1)  Bring up an image in RGB.
2)  Set up a custom color proofing dialogue with the CYMK Swop 2 profile, without Simulate PaperColor or Simulate Black Point checked, but with BPC on?
3)  Duplicate the original image, then try to tweak the softproofed one to look as much like the original as possible.

Or:
1) bring up an image in RGB.
2) duplicate the image and convert it to CYMK
3) Tweak it to look as close to the RGB as possible, and then save it with the tweaked layers flattened?

Will I be able to see out of gamut colors in either of these setups?  Or am I grossly oversimplifying the process, and need to start from the zero point on the learning curve?

Don't tweak the CMYK image - you may cross the TAC (total area coverage) specified by the standard. You should tweak the softproofed RGB image with perceptual intent, and simulate paper color on. I don't know US printing standards, so I only suppose Coated SWOP #3 profile should be ok for a glossy magazine - but you'd better ask them. Wide gamut LCD display should cover the majority of CMYK SWOP Coated color space, so I wouldn't bother that much about out of gamut colors.
« Last Edit: February 24, 2009, 06:44:42 PM by Czornyj » Logged

k bennett
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« Reply #3 on: February 24, 2009, 06:56:01 PM »
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Quote from: walter.sk
The images need to be CYMK rather than RGB.


Seriously? I do a lot of magazine  and sheet-fed CMYK production work, and I would NEVER ask the photographer to supply the CMYK file. Good results depend heavily on the actual press, not just the profile used. Also, final output sharpening requires that the file be sized first -- did they give you a percentage based on an FPO that you supplied?

If they give you a profile, then just make the best possible RGB file, and do a Convert to Profile to the target profile. Don't do any tweaking on the CMYK. I usually add a little saturation and bump the local contrast before making the conversion, but that depends on the file and the press conditions.
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pfigen
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« Reply #4 on: February 25, 2009, 12:40:15 AM »
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Walter,

As a commercial photographer who specialized in CMYK (as well as RGB) I have to advise you to be very careful in areas where you have no expertise. Your absolutely need more information from the magazine about the printing or proofing conditions. You can't just assume that SWOPv2 is appropriate unless they specifically tell you so.

When you get specific and correct profile information, and assuming you have a calibrated system and have properly set the endpoints in your original file, you should be able to take their profile and make a decent conversion. As long as your image doesn't have problem areas of high saturation or other problem colors, you should be okay. Those more experienced in CMYK will then check the CMYK file for proper white and black ink percentages as well as working to tweak specific colors as needed, and then sharpen properly for output. You may or may not feel comfortable with all of this. Communicate with the prepress department and make sure you all are on the same page. Without the proper communication, you're just shooting in the dark.

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Damo77
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« Reply #5 on: February 25, 2009, 03:12:04 AM »
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Quote from: walter.sk
Or:
1) bring up an image in RGB.
2) duplicate the image and convert it to CYMK
3) Tweak it to look as close to the RGB as possible, and then save it with the tweaked layers flattened?
Definitely don't choose this method.  If problems are going to occur with gamuts, the damage will be inflicted at conversion, and no amount of tweaking afterwards will help.
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Damien
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« Reply #6 on: February 25, 2009, 08:33:19 AM »
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I'd worry far less about out of gamut colors then colors that are way off due to the improper use of the correct ICC profile for the print conditions. Lots and lots of shops say they conform to SWOP when they are a mile off. Make sure that indeed they are conforming to a modern print condition and that you use the profile that defines that process (its probably not U.S. Web Coated (SWOP)!

Make sure you have some delivery notice or paper work that guarantees that if color issues happen on press, you're not responsible (you didn't ask for this). Or make sure you've nailed this by doing all the proper testing, including some true contract proofs, get the job done well and charge a boatload of money.
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Andrew Rodney
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walter.sk
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« Reply #7 on: February 25, 2009, 08:54:55 AM »
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Quote from: digitaldog
I'd worry far less about out of gamut colors then colors that are way off due to the improper use of the correct ICC profile for the print conditions. Lots and lots of shops say they conform to SWOP when they are a mile off. Make sure that indeed they are conforming to a modern print condition and that you use the profile that defines that process (its probably not U.S. Web Coated (SWOP)!

Make sure you have some delivery notice or paper work that guarantees that if color issues happen on press, you're not responsible (you didn't ask for this). Or make sure you've nailed this by doing all the proper testing, including some true contract proofs, get the job done well and charge a boatload of money.

Thanks all for the advice.  I will call the publisher to find out as much as I can about what they think they want.  It is actually for a new magazine that has solicited entries that, if selected, will be published.  It is a sister magazine to one that has a good track record and does a beautiful job with the photos they print.
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neil snape
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« Reply #8 on: March 06, 2009, 09:11:02 AM »
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Quote from: walter.sk
Most of the bruises acquired in the fight to learn color management for my RGB images, monitor, printer, softproofing, etc, have begun to heal.  All of a sudden, I need to submit some images on a CD, with possible printing in a photography magazine that prints high quality on glossy (slick?) paper.  The images need to be CYMK rather than RGB.

Am I correct in assuming the process would be similar to softproofing for my printer, as follows:

1)  Bring up an image in RGB.
2)  Set up a custom color proofing dialogue with the CYMK Swop 2 profile, without Simulate PaperColor or Simulate Black Point checked, but with BPC on?
3)  Duplicate the original image, then try to tweak the softproofed one to look as much like the original as possible.

Or:
1) bring up an image in RGB.
2) duplicate the image and convert it to CYMK
3) Tweak it to look as close to the RGB as possible, and then save it with the tweaked layers flattened?

Will I be able to see out of gamut colors in either of these setups?  Or am I grossly oversimplifying the process, and need to start from the zero point on the learning curve?



Well the only thing I wouldn't do is use paper white or any BPC for proofing.

I would and do; duplicate the image, convert to CMYK, proof that to my desktop printer with ICC profiles WITHOUT BPC in relative. This gives me a <dE 1.5 to Fogra 39 MW2 on my lowly HP 9180 through the driver from Photoshop.
So not flawless, but so close that I will bet anything that it is printable, and the press ops job is then to come close or improve it on press but in no way will there be a lesser quality than the proof.

Don't save out layers for images on press, it's just not secure.
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