Couldn’t find a thread for this yet (not a recent one anyway) so started one, and starting selfishly with a question as well…
So: If images on screen need to be in RGB mode and anything going to print needs to be in CMYK, how do I check that the colors are right on screen before sending something off to print…? If a screen cannot reproduce CMYK colors.
This has to be quite simple, my precious brain just can’t quite process it. :smack:
We always made color keys just to be sure.
The rare occasions that the negs came out in RGB? No image on the black negative/plate.
The colors on the monitor aren’t ever going to exactly reflect what you’ll see on the page. The only way I know of to ensure that your colors will be as you expect them when working with graphics is to use something like the Pantone System.
I haven’t done enough printing of digital photography to provide advice on that. However, my guess is that unless you’ve had your monitor and printer calibrated, it’s going to be difficult to predict how the print will turn out without some trial and error.
It’s not simple, we just expect it to be ;).
The RGB color space is lots bigger than the CMYK color space. This little graphic shows that CMYK is entirely a subset of RGB. So, if your monitor/printer/software are reasonably calibrated, you’ll have a good idea of how the printed piece will look.
You can never really see how reflective art is going to look, based on what your glowing monitor shows. If it’s really important, you go watch the printer run some test prints.
Thinking about these issues used to be my full time gig. Lots of correct info already in this thread, but here’s how we solved for this problem at the last job where I had responsibility for print…
[ol]
[li]Calibrate your monitor. Much easier in these LCD days. CRTs were a bastard to keep in line.[/li][li]Control your viewing environment. Some calibration tools will help you set the ambient lighting correctly. This is more important if you are comparing the screen to an already printed piece, for example.[/li][li]Set up Photoshop to correctly simulate the CMYK space you will be using. Get the correct CMYK profile from your print vendor. When in doubt, use SWOP if you’re printing to a web press, GRACoL if printing sheetfed.[/li][li]Print your pieces using the correct settings to a digital proofer. Basically a glorified ink jet tailored for press simulation with special software to facilitate that.[/li][li]If still in doubt, ask your print vendor to pull their own proof. [/li][/ol]
Any one of those steps could devolve into hours of discussion for the truly dedicated. Then we can start talking about which RGB working space (there are dozens of reasonable alternatives) and which CMYK output space (hundreds of thousands of possibilities, maybe more).
All of the above, plus if you’re getting photographic prints made, the file often does not go into CMYK because it’s not a four-color process. All the labs I use want sRGB (even for the press printed stuff, actually.) You want to get the color profiles of the printer and use soft proofing to simulate the output, in addition to color calibrating your workflow. It is a fairly complex topic. Personally, I just use a Spyder Pro color calibrator and find the results pretty accurate without even having to bother with soft proofing, at least for glossy photographic prints. For matte papers, watercolor paper, canvas, etc., soft proofing does help you better visualize how the colors and contrast are affected by those materials.
To clarify a bit about Pantone books:
Pantone (at least what most people mean by Pantone numbers) is a system for specifying pigmented inks. But these days, the majority of printing is four-color process, which is to say CMYK. It makes me nuts when well-educated (and well-paid) designers tell me the CMYK palette they want me to use *by citing a couple of three-digit Pantone numbers. * Some Pantone inks fall well outside the gamut that CMYK can reproduce.
Pantone does make other books, including ones used for interior (paint and fabric) finishes, and a CMYK book used to specify CMYK formulas. But based on 20 years of conversations with, um, designers, I seem to have bought the only copy ever sold.
Thanks so much everyone, I really appreciate your help. The printer specs says to use: PDF X3 - 2003 with colour profile ISO Coated v2 (ECI). (Full specs here). They offers proofs actually, either digital or paper, but its an online service so cant really go over to compare print outs or anything. And digital proof would not look exactly correct on screen anyway right? So I guess I’ll just have to use the right specs and trust the photos will print correctly?
Again many thanks for helping out! 
All bets are off if you don’t use a calibrated work flow!
Yep. You can guesstimate using “sanity checks” and the color picker and seeing CMYK values and get pretty confident in making a reasonable print, but a color calibrated workflow is really the way to go. And it’s not that expensive (<$200) to get the equipment to do so.
It must be possible, I’m here, aren’t I?!
Until the Grapist returns, you look just K on my screen.
Hmm, maybe I’ll do that if I actually start making money off this, absolutely skint right now 
Number three and four, definitely.
If you’re trying to do print work, for pay, and color matching is critical, I don’t know of any inexpensive way to solve the issue. It’s not as much a matter of worrying about RGB and CMYK color spaces, because if you’re designing for print you design using CMYK color mixes and the document/file and the print stage should be in step.
The problem you’re describing is inaccurate color representation on your monitor, which is always a PITA, given the color space mismatch, and is much worse when you’re using consumer-grade gear. (My daughter ramped up into semi-pro territory very fast, using a system built for gaming, and had some horrid color issues getting from her badly adjusted display to my commercial-grade printer. I think that’s a very common situation with run-of-the-mill systems adjusted to “look nice” rather than be accurate.)
So until you hit pro status and can afford a calibrated color loop and a graphics-grade video system and a printer that can be calibrated using a profile…
[ol]
[li]Work with pro tools that really understand CMYK. That pretty much means Adobe and not much else. Like Porsche, there just ain’t no substitute. (The difference between Photoshop Elements and Photoshop, for example, besides about $800, is that the former has PS’s mighty CMYK engine removed.) You can’t use lesser tools that are kind of faking it in the CMYK game.[/li][li]Work exclusively in CMYK once you are getting towards print. You have to stay in RGB for all the filters and adjustment tools to work, which is kind of a PITA, but convert a copy to CYMK when you’re “almost there.”[/li][li]Print to a good CMYK printer when you can, or try to find a color profile for your (hopefully upper-end) consumer printer. Make sure the printer driver is set to use CMYK throughout, and is not doing any conversion or correction itself unless it’s to apply the profile. (In general, a color matching profile should be applied by the software, or the printer, but never both.) Compare output from a pro press or printer with your samples, and keep adjusting.[/li][li](The important part.) Adjust your monitor to match a good printed CMYK-to-CMYK sample. With patience, you can get the colors and color levels to match pretty well, even with a lower-end video system and monitor. Tweak this setting from time to time. Get used to the subtle differences so you can get the print stuff right from the beginning.[/li][/ol]
I know more than a few part timers who do well with this approach. It does make everything else look like sh*t on your monitor - dark, washed out, “off” if you’re used to running things in gamer/browser/torch mode. But you’re moving out of “oh, that looks nice” territory, it seems. 
