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RGB to CMYK, pantone spot color help

Dec 16, 2010 6:06 PM

Hi guys,

I'm not sure if I have a problem with my color setup or my end result will come different than what I see on display, or if its just that I don't have too much pantone print/spot color experience but I can't remember having this issue too much before.

I have created a bunch of graphics for a website, which now have to be converted to CMYK for print. After I convert the color profile from RGB to CMYK, the main blue I use and all of that blues related tints/highlights and shadows are WAY out. Basically when I look at the Pantone Color Bridge if you look at blue 2935C (which is the correct blue) after converting to CMYK you see that awful dull PC version of the blue as shown in the Color Bridge which is as expected.

However when I load up the Pantone solid coated swatches in photshop the swatch itself looks about the same as what I see on the printed pantone color chip but when I use the swatch on graphics on my piece of work the color looks more flat/dull lifeless blue. Is this what is meant to happen? I just ignore what the computer output is giving me?

And does this mean I have to use a spot color to specify the good 2935C in this piece of work?

If so is there an easy way to specify/change the yuk blue to the good blue on all my layers? As I have a whole bunch of them.

Any help or advice would be great

 
Replies
  • Currently Being Moderated
    Dec 16, 2010 11:12 PM   in reply to TF22Raptor2

    You really need to read up on print production! First, the only way to print a spot color as a spot color is to define it as such, meaning Multichannel mode. otherwise there may never be a way to retain the colors in basic CMYK composite mode, since CMYK has a much lower gamut range. Second, conversion of the colors also depends on your color profile settings. If those are not correct, the result will get even worse. Still, in any case, the behavior you see is expected. You just have your workflow completely wrong. All areas that are supposed to be blue will have to be isolated and adjusted separately, but that really comes down to what you actualyl need to do. Also note, that "bright" colors in print almost always are printed with reduced densities/ opacities, so more light reflects from the paper. You may also need to do that, in particular if you only have composite CMYK and cannot use genuine spot colors...

     

    Mylenium

     
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  • Currently Being Moderated
    Dec 17, 2010 12:51 AM   in reply to Mylenium

    I looked at 2935C on my Artisan earlier, and while it is certainly a deep saturated blue, it didn't lose nearly as much as I thought it might when converting to CMYK. When you say it looks dull and lifeless, what CMYK profile were you converting to or previewing in? That can make all the difference in the world, and of course, you do have to use the correct profile for the job.

     

    My guess, and this is from printing thousands of CMYK print jobs in the last fifteen years, is that you can print that color with normal inks and be more than happy with it. What you see on the printed page will look just fine. Yes, it will be slightly duller than your computer screen, but it's not going to be so far off that people will scream. Now, if your client absolutely insists, you can do a spot fifth color, but for this I doubt it's worth the effort or the money.

     

    Also - the perception of how "blue" a color looks in print is greatly affected by what is next to it on the page. If you have a bright yellow or orange, that extra color contrast will trick your eye into believing that the blue is bluer and more saturated than it really is. This is the kind of trick professional designer and prepress professional use all the time to same time and money on press and deliver jobs that their clients love.

     

    After you do convert to CMYK, it's always a good idea to use the Selective Color tool and see if minor tweaking to the colors you're interested in can add the proper spice to the recipe. For blues, it's making sure that you've got enough Cyan, usually between 90 and 100 percent and keeping a sharp eye on the Magenta, which can range anywhere from 50-ish to 70-ish. You generally want to fudge the Magenta down rather than up, as blues on press almost always want to pick up more magenta and look too purple as a result.

     

    Good luck.

     
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  • Currently Being Moderated
    Dec 17, 2010 4:47 AM   in reply to TF22Raptor2

    To repeat what Millenium has correctly said TF22Raptor2 and p_d_f - Pantone colors and CMYK are not interchangeable. It is not possible to convert a Pantone color to CMYK accurately.

     

    Why is this this the case? 1. Because printing conditions are too variable for that. The color values in any CMYK file will print totally differently on a different printer. In real terms, CMYK values mean nothing accurate, and refer only very loosely to color. Pantones on the other hand refer to very specific measurable colors under specific lighting conditions. 2. The gamut (range of colors) available in CMYK is much too narrow to include some of the highly saturated colors available in a Pantone book.

     
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  • Currently Being Moderated
    Dec 19, 2010 5:42 PM   in reply to TF22Raptor2

    You do realize that CMYK can't print saturated reds, green or blues, right?

     

    Yes, if a color is out of gamut, it will lose some saturation, and may change lightness a little.

     

    Have you tried the gamut preview on your RGB image to see what colors are out of gamut for your chosen CMYK profile?

     
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  • Currently Being Moderated
    Dec 20, 2010 10:44 AM   in reply to TF22Raptor2

    You are running in circles, frankly, because you do not understand the difference between sport color printing and composite CMYK it would seem. Unless you print your blue from a separate plate where it is used directly out of the pantone mixing pot (i.e. physically mixed/ pigmented at the ink paste level), it wil lalways lose saturation. Your whole workflow therfore is unsuitable to retain these colors properly. You really must create a separate selection for this particular blue, store it as a custom channel in a multichannel doc and simply ignore the screen simulation for CMYK. This will only fully unfold when it's printed (assuming your printer provides these options).

     

    Mylenium

     
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  • Currently Being Moderated
    Dec 22, 2010 2:23 PM   in reply to TF22Raptor2
    Am seeing even if the printer can do spot colors.

    No it can't. Spot colors are specific mixed inks, produced by manufacturers in an attempt to create reasonably precise VISUAL values. An impossible task, because the lighting conditions by which any printed color is viewed, varies so much.

     

    The truth about color and color accuracy is as follows: all color perception is relative. We only perceive color based on surroundings. Precisely the same measurable red will appear differently based on its context. Our eyes, filtered through our brains, adapt the way we perceive color all the time. Many years and many idiots trying to prove otherwise has proved only one thing, color itself is not a nailed down set of rules. Very philosophical.

     
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  • Currently Being Moderated
    Dec 22, 2010 3:28 PM   in reply to Reynolds (Mark)

    I think Raptor means "they" the printer, not "it' the printer.

     
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