CMYK -Help!

Pardon my ignorance, but ive never had to convert to CMYK before. Well, im doing a postcard which requires the conversion, and as luck would have it the image is mostly shades of blue, so the conversion looks hideous--gray and dull. Is what i see in the monitor how it will likely appear in print? Is there any way to salvage the vibrant colors of the orignal RGB? Any help appreciated.

Changing the Image>Mode to CMYK does tend to flatten or grey out the color. Try readjusting the separate channels using the curves adjustment.

It's been a while, but in the good old days (bad old days?) when I did such things, you had the best results in the end if you knew the ink and printer being used by the offset. Have you received setting recommendations from your printer? If not, maybe I'm waaaay too out of date. Won't be the first time!

Hi if your monitor is correctly calibrated shanging to CMYK should not actually change the colours, what it actually does is put each colur into invisable layers that the printer requires to print each individual colour across the entire page, where rgb colour printers puts the colours down together in strips on each pass, whereas CMYK fills the whole page with one colour before applying the next colour ie. cyan then magenta then applying yellow followed by the black.

Hope this helps

Dave

Hey Stan,

I do postcards and rack cards regularly in CMYK. If you have the full CS from Adobe, you can do this in InDesign. Place your image and text then export as a pdf. InDesign works in default CMYK. I've always had a WYSIWYG experience with no surprises. Hope this helps or if you've got other questions, drop me a line...

Are you assigning the colorspace in PS or converting?

Assigning it means that it takes any given color, say ABCDEF and whatever new color in CMYK that is, that is what it becomes. This will often change the appearance of the image. In this case, the numbers but not the colors are preserved.

Converting the colorspace means that color ABCDEF might really be a lot closer to ABC111 in the new space, so it changes the number to ABC111. There should be very little difference in the appearance of the image after this is done. In this case, the numbers are changed but the colors are (reasonably) preserved.

I don't know about other software, but I can only convert to CMYK - I can't assign it. And a caveat - I've never done a CMYK conversion. Ideally, you'd have a profile from the printer to convert to.

Anyway, Stan, another thing to check is to set your "Proof Setup" to CMYK, then check the gamut warnings. If a lot of the image is out of the CMYK gamut (which is pretty small) you're going to get a pretty big shift and maybe some oddity in the colors.

If that's the case you can try different rendering intents. If that doesn't help, I'd consider hand editing the colors to bring them more into gamut for CMYK. At least that way you've got finer control over what you're going to wind up with.

Stan,

Just another bit of input... I get 1000 postcards (4 color CMYK) for about $60 with a 1-2 day turnaround. Aqueous coat or UV coat. They look great, colors match my best Epson prints. Let me know if I can help.

Stan, Most everyone here knows more than I when it comes to a question like this, but I would like to add this. I saw some of my images on a computer at a high quality magazine publisher. They don't do the printing but they did convert to cmyk getting ready to publish. The colors I saw on there monitor were over saturated, but the images printed in the magazine were much closer to what I had. They told me that they were in cmyk and not to worry about the over saturated look on there monitor. They were right. Not sure if this is the same thing you are talking about, but that was my experiance.

Nick Bristol
Lone Rock, Wi

Blue is an especially problematic color in CMYK. RGB color blues are not duplicatable in CMYK period. You have to get used to it. Surprisingly, when you have no context of an RGB image to look at, and you have to live within the world of CMYK, you don't really notice it that much.

Rich G

Stan, I do not know if this is any use, but I can sympathize with your frustrations I have recently been working with a printing company used to working in CMYK and it was a struggle! Eventually they got it about right after various trials and errors and instructions from a specialist working for the printer dealership, but involving no conversion to the CMYK color profile. I do not know the exact techs on how they accomplished it, but I do know that each time the four letters CMYK were involved it was always very different from what I saw on my screen. So if you can, stay away from that profile!

I don't have the color tech knowledge to help with your exact question Stan, but I will share this. Just last week I ordered 1000 5x7 postcards. The printers instructions where to leave in rgb color profile and they would convert to cmyk (they except many other color profiles as well). They will make a cmyk .pdf file for viewing the conversion and for your approval before you have to commit to the order. The .pdf file looked exactly like my rgb file I had sent them. I was still skeptical because after all I was viewing this on a computer monitor and not the physical print. I placed the order and received the postcards 3 days ago. I couldn't be more pleased. There is only minimal (very minimal) difference between the postcard and the file as I see on my monitor in rgb or srgb as the case may be. As far as color goes maybe slightly flatter on contrast and slightly less color saturation but they do look very acceptable actually I was quite surprised at how good they did look. I keep my monitor calibrated on a regular basis and have never had any issues with any prints or these postcards.
The company I used for the cards was UPrinting

Thanks for all the responses, folks--sorry for the delay responding ive been out in the hills shooting. I think the problem is as Richard mentions above--this shot is almost all one shade of blue, and unfortunately that shade doesnt seem possible in CMYK--ive tried every profile and all sorts of curve adjustments etc---nothing helps, i can get the contrast close but the color looks either cyan or magenta--not blue! Brad--i converted other shiots of mine as a test, and they all came out reasonably close in the conversion--unfortunately this is a special case due to the almost monochrome nature of the photo. Spot colors probaby would help but im trying to get this done reasonably within expense. Ah well--ill keep trying!

this shot is almost all one shade of blue, and unfortunately that shade doesnt seem possible in CMYK--ive tried every profile and all sorts of curve adjustments etc---nothing helps, i can get the contrast close but the color looks either cyan or magenta--not blue!

Stan, did you try a 'Selective Color' adjustment layer? You can work on each CMYK, and/or RGB channel separately. This has gotten me out of a color balance pickel more than once.

--P

Yep, tried that--no luck! I even reprocessed the shot from scratch, with CMYK to start out with, and i got it half-way decent, but i still prefer the color of the RGB.

Stan, you have the press specs for the CMYK file ?
Coated, Uncoated, web or sheetfed, total ink not to exceed 300 or 320 ?
If you want, send me the file, and I'll convert it for you. I have some very nice profiles for press.