When to use RGB or CMYK in print?

[Scubasteve]

I know your supposed to always do print work in cmyk, but alot of my print work seems to have more accurate color if my final file is an RGB file rather then CMYK. I know the file must be reinturpreted by the printer as a CMYK file, but often the results are better then I could have done, had I readjusted the file in photoshop myself. Does anyone else encounter this as well? Maybe it just means I suck at color correction... Anyway, I would love to hear how you pros handle the conversion and/or which you work in. PEACE!

[Elwell]

If you're printing out stuff on your home printer, stick with RGB. That's the color space that inkjet printers are programmed for, and they'll do the necessary conversions automatically. If you're sending something out to be printed in four color offset, you may be better off doing the conversion to CMYK yourself, assuming you have your monitor calibrated and are using the right profiles.

[Ilaekae]

Elwell's right. A pro graphics house will always RIP as a CMYK file, because that's the only valid possibility they have, and if you don't have your art already in that form, you only have yourself to blame when the results go bad.

Non-postscript printers are nearly always RGB since their biggest market is the public, which is not known for its graphic arts knowledge. If you get a good result off whatever you're doing, and that's as far as it's going to go (for example, you aren't going to mass produce it by litho later), keep doing what you're doing. Otherwise, get yourself up to CMYK professional level as far as your monitor, etc., are concerned...

What it boils down to is ...who should be in control of your final desired result? You...or some machine/stripper/output technician?

[nightfend]

Well I guess it really depends on your technical skill in color correction on whether you should convert it to CMYK yourself or let the service bureau do it.

If you aren't actually laying out the design that goes with the image, then sending a hi-res RGB would probably be fine as you know a professional will convert your art. Still they aren't miracle workers, and if your piece has a lot of medium blues and oranges, you may end up finding out that your CMYK'd version is much less saturated than your original piece.

Different presses have different ink densities, so if it's an offset press with a max ink density of say 300, you are probably okay just converting it yourself in Photoshop (unless it has a lot of blues or oranges as I mentioned earlier). But if you are producing for a web press (newspaper, etc.) The ink density will be much lower down in the 265 (for cold set web) and 286 (for heatset).

I find it's actually worse to work on a CMYK piece that has too high of an ink density as you have to convert it back to RGB and then convert it once more to CMYK at the reduced setting. This back and forth conversion can cause banding in gradients and just end up looking bad.

All of this doesn't even take into account the different ink gains that paper stocks have. So for instance if you are printing on uncoated stock, you'll want to bump the gamma of the image up overall (making it lighter) so the image won't print dark on the press.

There's a lot of variables, so it's not a cut and dry answer. Whatever choice you make (whether to send an RGB or CMYK), be sure and keep your original source file in RGB. Trying to do color corrections and other image work on CMYK only images can really degrade the quality. Also, the newer versions of Photoshop (I believe 10, CS, and CS2) allows you to view a false CMYK image of your RGB file. You can do this by pressing CTRL-Y (on the PC). This is a great way to make sure your art isn't too saturated with color.

[Marie]

hey thanks for this thread, this is something I should of been familiar with and wasn't. Its great to see useful information like this being shared :)

I realize I could of found it if I looked, its just the remembering that Im supposed to look for something thing that gets me.

I am going to have to give this subject a lot more research. Especially on calibration... that is what confuses me quite a bit. Since I was doing little things for people that they had planned to print out, its something I need to be familiar with.

again, thanks for the very useful information.

[Scubasteve]

Good points guys.

nightfend - I wasn't aware of that option in CS. Thats a cool new feature, I'll definatly be using that one.

[Jason Snair]

Just wanted to add a simple tip.

I'm an art director for a newspaper so I'm usually the one who ends up converting a lot of RGB images into CMYK.

If you're unhappy with the outcome of a CMYK image after converting it from RGB, (while in Photoshop) simply click on the image menu bar and scroll down to adjustments. Click on Hue/Saturation. A new window will open up with a bunch of adjustment bars. If you make the image a little more saturated, like say plus 3-5, usually the new CMYK image will look a lot closer to the original RGB. And as a plus, your reds & oranges (if you have them in an image - that is) will print much more vibrant, fuller and closer to the real thing.

hope that helps some.
-jason

[jrr]

well with newspapers you gotta keep in mind with the ink density, the max is 240 (newsprint). and with b/w you usually gotta keep the k to under 85.

[darth massacre]

Just remember....no matter how well you calibrate your colors on YOUR system....it will always screw up if you bring it to the commercial printers :teeth:


And its never their fault ......


This is what I hear from my friend.

CMYK - for 4 colors offset printing. Usually printed in quantity
RGB - for digital laser printing. Flat rate, cheaper if you just have a couple of pieces to print.

Or just use pantones for flat colored stuff but they'll cost ya.

[figure2]

Just remember....no matter how well you calibrate your colors on YOUR system....it will always screw up if you bring it to the commercial printers


And its never their fault ......Most commercial printers have a "specs" page on their web site where they give detailed instructions on how to prepare artwork for their presses. One size does not fit all as different printers may have different requirements. If you don't bother to find this stuff out, then it really is your fault if it turns out bad. In some cases for an extra fee, you can get a "press proof" to see what the final printed piece will look like before it actually goes on press. If the option is available it is almost always a good idea to spend the extra cash. Once you approve the proof, the printer is "locked in" to giving you those results.