CMYK cannot reproduce the colors in RGB. I'm pretty sure this is covered in the help, or any basic design class.
Thanks for reply...
I understand what RGB and CMYK is. Now I have already designed around 50 pages which follow RGB and want to give them for printing. Conversion makes them very ugly. It would be great if you let me know the exact settings so that differences are subtle.
If you understand the difference between RGB/CMYK and everything included in the links that I provided then you should not be surprised by the difference in conversion.
There are no "exact settings" to squeeze an elephant into a compact automobile. Not all of the elephant will fit.
What part of the links that I provided do not make sense to you?
I understand what RGB and CMYK is
Erm, no offense, but my impression is the exact opposite. It's exactly as Marian said - you started off on the wrong foot. There is no way to get a "lossless" conversion from RGB to CMYK, especially if saturated, bright colors are involved that cannot be mixed from the component inks with limited gamut. Aside from that, you naturally have invited a ton of issues from badly printing text or items unnecessarily getting rasterized to pixel data when the otherwise could be retained as vectors for better/ sharper printing. And even if you started out in CMYK, you'd still have to use some form of color management as different printing processes still produce different results even in CMYK. Color profiles and al lthat stuff do matter, believe it or not....
Not the cure but a prescription. Group your layers and save them as another. Then create those files as 'PNG' formate, drop the png files in your CMYK covert document and remove the dull desaturated images with the PNG substitute.
codemankino: And that would give you exactly the same result as if you converted the layered file from RGB to CMYK in the first place.
A lot depends on the particular colors you're using in RGB, what sort of CMYK printer or press you're using and just how you're actually converting to CMYK. Most images print just fine in CMYK, as can be seen by the many thousands that print every day in magazines and newspapers around the world. CMYK's weakest areas are bright saturated blues, which will always print like crap because the inks just cannot print those colors. You haven't told anyone exactly why your conversions look like crap, only that they do. If you posted an example, more specific help could be given, but the bottom line is that there are always going to be some compromises going to press and you, as the designer, have to take those possibilities into account when doing your design. You can also trick the viewer's eyes into thinking the image is more saturated than it really is by intelligent use of color contrasts in images and designs. For instance, using a bright yellow, something that presses print quite well, next to the best blue you can print, will make that blue appear bluer and more saturated than it really is. Of course, if you need exact and specific color matches, you can always go to additional spot color plates using Pantone or other color inks, at an added cost in both money and complexity.
Entire books have been written on this subject, and for good reason.
You fail to mention which RGB-space you are working in and which CMYK-space the images will be printed in.
Anyway, it might pay off to decide on the Render Intent on an image-by-image basis, as Perceptual and Relative Colorimetric may produce quite different results.