RGB simulates additive colour (as in TV scvreens and monitors)
CMYK simulates process inks (as in most of the colour stuff you see printed)
You normally work in RGB and convert to CMYK just before sending your file to print (Keep a master copy in RGB!)
300 ppi (pixels per inch, not quite the same thing as dpi, dots per inch) is good for most project (in fact it’s overkill for many) so you should be fine working at that resolution.
You normally work in RGB and convert to CMYK just before sending your file to print (Keep a master copy in RGB!)
Many designers for print will start in CMYK. Read the help files on gamut to see why. Colors can shift if you start in RGB and then convert. Nomad probably is aware enough about gamut problems to avoid this, but many new designers fall into the trap and complain when the shift happens.
There are limitations to working in CMYK, with some (many?) filters not working in that mode. If you need those, then you have to convert to RGB, then back to CMYK. In those cases, you would have been better to start in RGB.
You normally work in RGB and convert to CMYK just before sending your file to print (Keep a master copy in RGB!)
A slight amendment to rule 101:
You normally work in RGB with a reasonable profile, previsualize in the most likely CMYK and convert to CMYK just before sending your file to print (Keep a master copy in RGB!).
Thank you for your explanations.