Any of you who have at least little experience with graphic design software, photography or professional printing, must have -almost undoubtedly- have gone through this: 'the struggle' of RGB and CMYK colour spaces.
Now, there are many questions regarding matters of 'which should I choose', 'what is what' and converting problems, but that's not really what I'm after here.
As a graphic designer with only a couple of years of experience, I still have this struggle from time, and find the whole CMYK/RGB choosing/converting/saving situation quite confusing, to say the least. I do know that RGB is meant for digital end purposes, and CMYK is suitable for printing.
I have always been wondering about the neccesity of this whole thing. So, my question is: why are there these two colour profiles, instead of just having one?
Wouldn't it be a lot easier if printers or software could convert any RGB file to a CMYK printing document instead? I'm pretty sure it does already exist, by the way, because printing an RGB file sometimes simply prints the right colours for me. Alas, not always (doesn't seem to be related to the printer of software I print from).
I have gone trough some RGB vs. CMYK-related questions and found this, a.o., (on this page), an answer of user DKuntz2 (thanks DKuntz2):
RGB is a light-based theory. All colors begin with black "darkness", to which different color "lights" are added to produce visible colors. RGB "maxes" at white, which is the equivalent of having all "lights" on at full brightness (red, green, blue).
CMYK is a color-based theory. All colors start with white "paper", to which different color "inks" are added to produce output colors. CMYK "maxes" at black, at which point all "inks" are applied at 100% (cyan, magenta, yellow, black).
Not sure if this is entirely right, though, because some people disagreed with DKuntz2:
I disagree. With RGB you start with black - the absence of light; with CMYK you start with white paper.
Although this does clarify the differences fairly well, I still don't see the point of the two colour profiles(/spaces)
Side question: What happens when you work in an RGB document in photoshop, then press
ctrl+y? Photoshop says the document is
RGB/8/CMYK, but it can't be both. Right?
Big thanks for the answers, the (current) three below are very informative and interesting. I understand the whole thing a bit better, although it's all very complicated and in-depth to me. Especially when I read about terms like colour models, colour profiles, colour spaces, colour spectra and gamut all one after another.
As much as I would like to accept an answer as the desired one, I feel that my question in the core isn't fully answered yet. What I would really like to emphasize is what I asked about earlier:
Wouldn't it be a lot easier if printers or software could convert any RGB file to a CMYK printing document instead?. As Alan Gilbertson explained, the reason is - if I understand correctly - basically a 'lost-in-translation' thing that makes the conversion not 100% accurate, and the colours to possibly be a bit distorted.
However, I still don't see how the solution cannot be an automated conversion done by a printer. Should be possible with modern technology; if you can convert RGB to CMYK in Photoshop, why can't a printer do the exact same for you? As was also said in the answers, the slightest differences in colours and colour spaces, can not be seen by the human eye. And that's what it all comes down to: what we want to see. Be it on a screen or on a sheet of paper.
The fact that this question has three very long answers, or even moreso the fact that there are so many questions about these two colour models (I now know the right term, yay) kind of proves that this is way more complicated than it should be.