A color working space is one of various standard, device-independent color space, such as ProPhoto RGB, Adobe RGB, sRGB, CMYK, etc. I have listed these examples in decreasing order of the gamut or range of colors each of them can cover. Of the ones in this group, ProPhoto RGB is the widest one of the four listed here, containing the most colors. CMYK is the narrowest, with the most limited gamut or range of colors.
A target or printer profile is a device-dependent profile specific to a given combination of printer, inks and paper.
Always use a device dependent-target profile to Soft Proof an image, never a working color space which by definition has to be device-independent.
Most of us work in the widest practical working space, such as ProPhotoRGB or Adobe RGB when generating an image for print and leave the conversion to CMYK to the very end, as the very last step in the production process. Always ask your printer (printing company) which specific target profile will be used by their equipment, one specific to the combination of printer, ink and paper to be used for the final output.
thanks for the reply
1. A colour space is a colour mode under a specific colour profile. E.g. RGB with ECI v2 (European Profile).
2. When you print and place the images in InDesign, leave them in RGB! Conversion from an RGB Colour Space to the Output Colour Space should be done upon PDF export (PDF X1a) or later (PDF X3 or X4), and always with the same working step as transparency flattening is done and never before.
All this theory is just that.
Adobe's RGB ideology of working spaces is good for about 85% of the image proccing needs for the masses. Technically a CMYK working space does not exist by defination, but we use a CMYK color space because the tools don't exist for ALL the requirements of print in RGB. So realistically, by defination, working spaces are broken so do what you want.