Printing/proofing CMYK

[Djuna_A_]

Okay, so I'm in the home stretch. Calibrated monitor, edited in RGB and then duplicated and converted to CMYK profile (Japan Color 2001 Coated)... destination: unspecified offset printer in Japan. I don't know the paper color, and I'm not going to see the proofs. So obviously I'm not going for perfection here. What I'm wondering is, would it be misleading to get the files printed out at a local laser printer place (they can do CMYK and keep my embedded profile, but their printer is not calibrated to that profile)? I mean, aside from just proofing them for scratches and sharpening... would the increased saturation of the laser printer just lead me astray? Should I just go with my monitor at this point for color, contrast, brightness...?

Thanks!

[D Fosse · Accepted solution]

A laser print is probably just misleading.

The big variables are white point and black point, and these should be set as calibration targets. Then you can soft proof and get a very reliable preview of what the finished result will look like.

Ideally you should make a direct comparison and try to match screen to an existing print, but if that's not possible a "generic" match shoud get you a long way.

Does your calibrator (or monitor OSD) let you set a black point? This is very important. If it does, you will probably end up around 1.0 - 1.8 cd/m², depending on the paper. This is nowhere near the native black point of any monitor, and the main reason for the common disappointment at the  finished result.

[D Fosse]

This is how you can do it in a calibrator that lets you store multiple calibration targets. Each of these corresponds to a certain output - note the different white and black points.

The only thing to remember is to relaunch Photoshop when switching targets, it has to load the corresponding profile at startup.

[Djuna_A_]

I have an X-Rite i1 Display Pro... will check out the black point settings. Thanks again!

[D Fosse]

In i1Profiler, the black point is given as a contrast ratio (IIRC). But it's the same thing - just do the math.

If your white point is 120 cd/m², and the contrast range is 300:1, then the black point is 0.4 cd/m².

And if your white point is 100 cd/m², and the black point is 0.25 cd/m², then the contrast ratio is 400:1.

[Djuna_A_]

D Fosse, I don't see any settings for contrast ratio (IIRC) here... and the white point is measured differently than the luminance. (These are the settings the guy at i1Pro suggested):

[D Fosse]

The white point has a luminance component, and a color component. I'm referring to the luminance component.

I haven't used i1Profiler for a long time, so maybe I don't remember correctly...

[Djuna_A_]

Argh. I was in "Beginner Settings."

For Contrast Ratio, I can choose "Native," "287:1", "Custom" or "From Printer Profile." I can also simply choose "Custom Black Point" with the value of 1.4 cd/m2... I'm guessing that's it?

[Djuna_A_]

Also, a question: Do I still select "Black Point Compensation" in the printer profile conversion at Photoshop after setting black point for my monitor?

[D Fosse]

Black point compensation should always be on. I can't think of any situation where you'd want to turn that off.

[D Fosse]

Well, I can't tell you what to pick because it's a purely visual match, heavily influenced by your whole working environment and what light you're viewing the print in. Just get them to match by adjusting the calibration parameters for white point (luminance and color!) and black point.

The aim of this exercise is to arrive at the holy grail: what you see is what you get. Meaning what you see on screen is a reliable representation of what the printed result will look like. The only way to do that is to adjust the screen. You can't adjust the paper itself or max ink coverage. Those are your given references.

The ideal way to do this is to have a printed sample of a file you already have on your computer. Compare directly, and try to match them. Try to "see" paper white on screen, and a black that is about the same depth. If you can't do that, get a print and a reasonably comparable image on screen.

[Djuna_A_]

Okay, thanks... I got everything but this: "Just get them to match by adjusting the calibration parameters for white point (luminance and color!) and black point."

I don't know how to "match" except that by following the default calibration parameters for white point (thank you, Google) plus the black point luminance setting you suggested: 1.0 - 1.8 cd/m². It seems to me that since I can't get a printed sample from the offset printer (I just have access to laser), I should calibrate my black point to the contrast ratio of the printer ("From Printer Profile")? And work in a dimly lit room, etc.