Attached Link: Very useful link!

I am sorry, but I must say that some of what killer3d says is nonsense. His or her words read like an alternative reality. The first sentence is so far from reality that I can't even grasp how he or she ever composed it. **CMYK** are the four color full-color print is made of: cyan, magenta, yellow and black (the 'K' comes from 'key'), when a document is printed (also on inkjetprinters) all colors you see in print are made out of these inks, mixed by printing them in small dots (screen). The more ink, the darker the color. **RGB** is the way colors are created by light on monitors and tv screens. Red, green and blue are the basic light colors, with which ANY known color can be created. The more light, the lighter the color. *(there is no connection whatsoever between cmyk and vectors and rgb and pixels... the only link could be that in Illustrator and Corel the standard modus is cmyk, but you can work in rgb if you want, as you can change your document in Photoshop to cmyk)* **Color Management** does NOT start when you are outputting to a service center, unless you REALLY like gambling, have all the time of your life and plenty of cash to spend on reprints and retrying and searching for other printers because the one you choose 'did a crappy job'. One of the reasons color management is needed is the big difference between watching colors on a piece of paper and watching colors on a pc screen. Because one is ink and another one is light. One of the biggest disappointments if you are learning yourself creating stuff on your computer and fiddling around in Photoshop, is printing your material, especially if it gets printed in off-set or similar professional processes and discover that a lot of your preciously chosen colors are somehow changed in to something that looks like an old painting that has been lying in the mud. The reason: in CMYK you can print a smaller range of colors than you can see on a tv or pc monitor. Especially the really bright colors on-screen (remember the red, green and blue) are dull when printed. So why does color managment come in to place earlier? It can help you working on what you can actually achieve when outputting stuff to paper, because it can make you see what the end result will be, instead of what a monitor can do. Actually, it is kind of logical. If printing is your end result, you should work toward that. The same would be true if you are designing a murial, you should only the paint you have bought... When making artwork (or designs and lay-out) there are several pieces of hardware in the workflow that collect or output color information, your scanner, your camera, your monitor, your inkjetprinter. The ideal situation is, that every part of the pipeline is build for the final result: print. There is not only a problem with the cmyk and rgb difference (it will be referred to as 'gamut' in documentation), another reality is, that a lot of hardware has standard handicaps that should be corrected in the process. For instance, lots of digital camera are simply taking too blue photographs. And lots of scanners' result is too red, especially when the lamps get older. That is why in your systems profiles are everywhere and you have all those choices in the dialog box. If you want to output on a professional level you will have to deal with these matters. Most print shops or printers will NOT accept documents that have mixes of RGB and CMYK in them. One of the reasons is that they do not want to be accused of doing a crappy job. They want you to know what the end result will be, color-wise, so you will pay them for what they deliver. I am a professional designer and have to deal with this stuff on a daily basis. I will try to do a short run-through of our handling of it: - Scans are made in CMYK. Well, not really ofcourse, a scanner works with light, not ink, but the software that comes with professional software does the conversion, compensating all characteristics of the scanner AND making the best cmyk version possible. This requires to make profiles for the scanner once every 3 months, because of the degenaration of the lights in the scanner. - If scans are delivered from external sources we will change the modus from rgb to cmyk (using the standard conversion of adobe) and corrected if needed. If there are drastic changes that will bother the client of people who sent the scans, we will make a jpg to show them how the result will look like (a jpg is in rgb again, but now only with colors that can be printed). - Digital photographs are converted from rgb to cmyk and corrected. If there is a profile embedded it will be taken into account. - Manipulations of color, collages, photo montages and whatever you want to use Photoshop for are mostly done in rgb, but mostly with material that has been changed to cmyk and back, to get rid of the colors that can not be printed (and are useless, actually). The documents are less 'heavy' (cmyk uses for channels of information, rgb three) and a lot of filters and layer effects are designed to work in rgb. - Lay-outs are made in InDesign (sometimes in Illustrator). In the design phase the mix between rgb and cmyk, mostly because it is just to much work to make a flat cmyk version after every change. But when looking at the screen, a lot of the time you want to see what you are making, not what is possible to make with light on a computer monitor. So before sending desings to a client (via pdf file most of the time) we will make everything cmyk. As a rule of thumb lay-outs are in cmyk. As for profiles: we do NOT embed profiles in our documents, because there is actually a unique profile for EVERY print machine (but people tend to generalize per model ;-) and a lot of time we do not know which machine will be used. So when saving photoshop files, NO profile is better than the wrong profile. More and more jobs are deliverd as high resolution pdf files (for advertisements we use Certified pdf files, that do require output profiles, that are standardized for all magazines and papers), which only will have the correct end result if they are built right. You do need to know this kind of stuff if things tend to get 'professional', otherwise you will 'sell' your stuff with a look that can not be achieved in print. That spells p.r.o.b.l.e.m. and can result in reprints that only have one payer, you. I found the link above very helpful. Sorry if I seem harsh, but I had to react to informatin that is wrong. I understand killer3d wants to help, but it seems his knowledge is a bit too hear-say. It will probably work for his way of working and understanding of the (print) world, a lot of other people could be brought to wrong conclusions.