Q about PS RGB and CMYK modes, printing

3d Design and graphics

Q about PS RGB and CMYK modes, printing

Postby Vigilante on 05/3/2012, 2:51 pm

I use Photoshop a lot, and often need to design something just for print. The printer we use is a Sharp MX-3110N. I'm having a hard time finding out how the printer handles color, but I assume it's a CMYK printer. Is that a wrong assumption?

Anyway, when I need to do something for print, I design in CMYK because I just always thought it's the best way, why not?
Here is the issue, I'm updating some old DVD covers that were designed a long time ago, in RGB mode. I'm moving them to a higher DPI, better template, and just basically making them better. My new DVD covers I designed in CMYK mode in Photoshop.

Everything is good except those freaking black colors! My small text I do in C0-M0-Y0-K100 which is fine. But for larger black areas and fonts, no black seems to print as black as the colors from the "old" RGB files. So for example:
OLD file, RGB Mode, black as rgb000, or cmyk as Photoshop's default C75-M68-Y67-K90.
NEW file, CMYK Mode, black as rbg000, CMYK as C75-M68-Y67-K90.

As you can see, the color that is selected in the color picker is the SAME in both files, identical RGB and CMYK values. But when printed, the RGB mode (old document) blacks are much darker and nicer, while the CMYK blacks are still faded out. In fact the entire RGB document prints just a bit darker in general.

Since the colors selected within the documents are the same, something is happening with the color Mode and conversion for the printer. All I want to know is how can I get my CMYK document to be blacker like the RGB document? Is it a color profile I have to change? Am I not set up for our copier correctly? I'm not sure where to set a color profile IN the document, though I do know that when I print, it's set for "Printer manages color".

Frankly I'm about to just quit designing in CMYK since our printer looks much nicer from RGB anyway. I don't get it. I feel like I "should" design in CMYK, but everything just doesn't look as nice as RGB Mode.

Note that I tried other combinations for black, I tried a pretty heavy C70-M50-Y30-K100 and it STILL wasn't as dark as the RGB document!

What's going on here?

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Re: Q about PS RGB and CMYK modes, printing

Postby Michael_Szalapski on 05/4/2012, 9:23 am

First rule of design. If it looks right, it is right. Go with what gets you the best result.

To answer some of your questions. All printers print in CMYK (some also add other colors to the mix like true red, true green, photo cyan, photo magenta, etc.), but CMYK is the base. You can't print in RGB. RBG is light mixing.

However, that doesn't mean that there's not a color management mismatch somewhere. Modern color printers (especially professional ones) can be really twitchy if you screw up anything along the way. Read up on your printer's color management features and see if you can suss it out.
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Re: Q about PS RGB and CMYK modes, printing

Postby Vigilante on 05/4/2012, 11:32 am

I read that most printers are NOT CMYK (true). Just because they have those color inks doesn't mean it's true CMYK process. You only find that in commercial process printers. I even read one place that said specifically that NO home based or inkjet printer is CMYK. Basically, the driver handles conversions and does the best it can. That's why I was confused about our copier, it's a big expensive machine, but not sure if it's a "true" CMYK or if this is just a driver issue.
The driver is toning down my CMYK docs, but making my RGB docs rich. I don't actually know WHERE or how to see how this printer handles anything. The properties of the printer certainly don't distinguish colors between CMYK and RGB prints, nor does it have anything about ICC profiles or whatever. So I'm just a bit lost. When we use professional printers they want documents in CMYK of course, so I keep designing in it, but we do some testing here before I send over there.

Just a lot of stuff ain't meshing, not sure where to start troubleshooting or fixing.

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Re: Q about PS RGB and CMYK modes, printing

Postby browntimmy on 05/4/2012, 9:46 pm

I don't know if this will help your situation, but at the printing place I used to work for, for blacks, we'd shoot for C=30 M=30 Y=30 K=100. I'd use the "selective color" adjustment and adjust the black settings to do this.
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Re: Q about PS RGB and CMYK modes, printing

Postby nico89-fx on 05/6/2012, 11:45 pm

@OP.. What you say is 'somewhat' true. However, every printer does print Cyan Magenta Yellow and Black unless otherwise specified (as mike mentioned). The thing is that some home printers can't process CMYK data coming from (for example) illustrator and have to convert it to rgb to be sent to the printer then back to CMYK to be printed. As is, there's two conversions going along the way, whereas there's only one if you are working on RGB. However, since you are gonna send this files someplace else and they require CMYK files, there's pretty little room for arguments: CMYK it is. Plus, given the wider gamut of RGB, you tend to overlook stuff like oversaturated colors that don't come out as expected, weird looking blues and such.
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Re: Q about PS RGB and CMYK modes, printing

Postby Vigilante on 05/7/2012, 8:49 am

Photoshop's default rich black is 300% coverage. It seems to me there is just no way to get a richer black out of a CMYK print job, since I can't go over 300%.
@browntimmy: 30/30/30/100 is only 190% coverage. Seems like that would be pretty mild!

I guess what it really boils down to is, if I design CMYK in Photoshop, a 300% black is still faded and maybe it's the best I can get out of the printer? OR I can go back to RGB designs and get richer prints which ARE possible.

The problem is RGB designs going through the copier is that on small fonts and so forth, you get the ghosting colors as I can't necessarily tell it to print with only the black toner as I can with CMYK.

Frankly, I know this will be an issue, so if I can't "fix" the printer driver to get some darker, richer prints, I'll have to just design in RGB. Doing that has its benefits though, such as smaller file sizes and more room for adjustments/effects/web. Then if I ever HAVE to print CMYK, I'll just convert and check it over. Of all the printing I've sent to this copier that is RGB, I've never really had a surprise color come out that wasn't near what I designed.
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