Photoshop: When I convert from RGB to CMYK, why is the color is different?

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When I try to convert from RGB to CMYK the color is different, any one can help
I use CS5
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Jamal T

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Posted 7 years ago

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Chris Cox

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How exactly is it different?

As explained many places, most CMYK printers don't have the same gamut as RGB displays: so many colors cannot be reproduced accurately in print (like bright reds, greens, and blues).

Also, the choice of CMYK profile will have an effect as well: plain paper printing has a much smaller gamut than glossy paper printing.

You can use the Proof Setup dialog to provide you with a preview of how your image will look in different CMYK profiles. Of course when you print you need to use the profile for your printer/press. And if you're printing on the desktop, you shouldn't be using CMYK at all because desktop printers speak RGB and not CMYK (converting would cause double losses on those printers).
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christoph pfaffenbichler, Champion

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Adding to what has been said:
The choice of words »convert from RGB to CMYK« without mention of either source- or target-profile (Color Space) leads me to believe that you might benefit from reading up on Color Management, as a starting point for example »Chapter 4: Color fundamentals« in the Photoshop Help.
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Jamal T

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Dears thanks for reply

what I want to say is this file is going to be print on commerical printer wich use CMYK profile.

my file is RGB because the background of the file photo originaly RGB, when I finish ed the design, and I converted it to CMYK, the color changed and become pale.

what is the best way to convert without color changing

thanks
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christoph pfaffenbichler, Champion

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CMYK and RGB are Color Modes and as such of a limited significance to the appearance of an image – the Color Space (usually in the form of an attached ICC-profile or the spaces set under Edit > Color Settings) allocates a defined appearance to the various possible combinations of R, G and B and C, M, Y and K respectively.
So if something will be printed in CMYK a highly relevant question is: What CMYK?
Ask your printer, because the standards vary.

»what is the best way to convert without color changing«
Under certain circumstances there is no way to so.
For example if the two Color Spaces (or rather the image’s content therein) lack a large overlap or the target one is much smaller than the source one.
The results of separation (Edit > Convert to Profile) can vary depending on the chosen settings like Intent (usually either Relative Colorimetric or Perceptive), Black Point Compensation ...
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Rahul Singh

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Unfortunately there is no such way. converting into CMYK will effect on colors because thats just how colors works. I recommend u start again with CMYK mode.
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christoph pfaffenbichler, Champion

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»I recommend u start again with CMYK mode.«
If the images are photographic I disagree.
Editing those in RGB usually makes sense even if they ultimately will be printed in CMYK.
And working in CMYK has its risks; it’s fairly easy to exceed the permissible Total Area Coverage with a couple of Adjustment Layers or Blend Modes for example.

Edit: In my opinion working in CMYK in Photoshop mainly makes sense with graphic and/or illustrative work where for example lines and/or text are intended to only print in black or certain areas are supposed to be printed with only one or two of the printing colors.