A question of Levels (1 Viewer)

Since RGB is a bigger color space, it makes sense to process images using Adobe RGB (1998) color space, or Color match, or whichever RGB color space you prefer.
CMYK, as was pointed out above is a smaller color space and can't reproduce some of the hues accurately and the printed version will often look a little duller due in CMYK mode.

There are two options to consider if you need to concern yourself with how an image may look when converted to CMYK. You can turn on the "out of Gamut" warning by highlighting it in the PS menu under View>gamut warning and correcting any gray shaded areas (that indicate out of gamut) that appear on your image. Do this by adding a Hue/Saturation adjustment layer and then adjusting the hue and lightness sliders to reduce any areas of grey shading.

Secondly, using the "soft-proof" options in PS from the drop down menu View>proof colors. You can then pick a profile from the drop-down list that will be assigned to render your image as it would appear, or a close approximation, if you were to convert it to CMYK. This is a soft proof. You can then adjust your image to modify it with a live view.

This will not change your RGB file as opposed to selecting Edit>convert to profile or Image>mode>cmyk which will alter the data in the image.

I don't have the scope or time to go more into it, but if you search the web, you can find many resources on how to use these simply and better explained than by me!

Again, it's a matter of degrees and for most people who don't do a lot of large prints or published work, it may be "overboard", but since I work in the creative arena, I try to prep all my files for print as best I can.

Then there is always the curve ball of colours that exist in the CMYK and the Adobe RGB spaces but can't be shown on a RGB monitor (unless you shell out ££££ on a ColorEdge), so you have your image, captured as a 12bit RAW, post processed in Adobe RGB and then printed in CMYK and there could be colours in it you've never seen!

What a lovely change of thread from the usual crop factor, noise issue and should I tape my convertor.

I am lucky in the fact that I do own equipment that would be the envy of most people on this forum. Mono would quite like to work for me!

With Photoshop, I’ve come to the conclusion that it has long been used as a ‘get out clause’ for bad photography.

I agree with Roy, that knowledge is a useful tool, and it is beyond me that people will spend thousands on camera equipment, and the images they produce look like they’ve been splashed with a bucket of grey paint.

I do disagree with a lot of tripe that is written and published, and I would question technically the author’s ability. I can justify that statement because I have been in the position as consultant to National, International Newspapers, Magazines and Companies on their conversion to digital production.

Colour correction is not a new phenomenon with the digital age, and did not come apparent with the creation of Adobe Photoshop.

I agree with Julian that it is up to individual to warrant how far they go with the subject. I can’t condense from all my years what I know into an article or procedure that can be easily read and applied and that’s why I would question so many of the quick fixes on colour correction.

pe'rigin has some valid points and I'm sure he has some advice that would be useful in a "real world" scenario.

Luckily I use Photoshop as part of my work, so when everything went digital, I didn't have such a steep learning curve from that end. However, there is so many layers of processing and color management that it can get stressful for a lot of people that want to just process digital images. As Mono stated, for many there will be perfectly acceptable images that look fine with minimal processing, but for me, I am more immersed in it since I am often involved in supplying files or prepping files for a third party, where it starts to get technical and costly if files are to be handed off to a vendor in a certain way. And, I need to know that it will print as close to my monitor as possible so nobody (client) freaks out when they get their purple, not blue logo printed!

I think every digital photographer should know how to set-up their Color Settings to a default, acceptable color spaces for RGB and CMYK and know to convert jpeg images for the web to sRGB to preserve quality. CMYK should not be a concern for most photographers. If need be, I refer you back to my original post.