In Photoshop 5.x or earlier the gamut warning is tied directly to the current CMYK Work Space set-up. So this is not much use unless you are after the CMYK WS gamut description.
The same for later versions - unless you use a softproof. The softproof profile would be the inkjet printer in question - which is most probably a RGB profile, and the input images should be RGB.
Generally most desktop output profiles are RGB - CMYK is more for press, although if you are into PostScript output on the desktop then CMYK is often the profiling space used.
If you are using a standard printer driver, then it is probably a RGB input for output. If using a PostScript printer driver - then CMYK is a good bet. As PostScript costs, most consumer devices do not use it - so it is often a good bet to say a given desktop output device is RGB based.
Here is the basic workflow recommended by most users for desktop printing:
* Acquire images and retain source ICC profile (scanner or camera) and then convert a copy of this data into your preferred safe neutral editing or Work Space RGB (Adobe RGB etc).
* Perform edits via adjustment layers and a softproof using the output profile, as the input colours may be out of gamut for the destination.
* Print the image, converting from the WS RGB to the printer RGB in the print colour management section.
** Using Adobe Gamma will not lead to the best possible monitor profile. The monitor profile is critical to display of accurate colour. Often a hardware/software package is used for this task, and the savings in ink/paper/frustration usually make this a no brainer as 'spyder' calibrators/profilers are quite cheap these days.
*** Using a canned or default profile of the printer will probably not lead to best results, but in some cases they do a OK job. A custom profile is often better. There are consultants and services to profile your printer with one particular brand of ink/stock and resolution which you do not change (or the ICC output profile for the printer is invalid). This saves buying expensive hard/sofware and having to learn how to profile yourself.
http://members.ozemail.com.au/~binar...V_links.html#E
The above link is more for Epson info, but in a broad sense most of the workflows are applicable to any stable output device.
Related info on colour settings and colour management is here:
http://members.ozemail.com.au/~binar...V_links.html#C http://members.ozemail.com.au/~binar...V_links.html#I
There is a wealth of info out there to be found on colour managed printing (ICC, PIM, manual methods etc). Try a web search - as it is too hard rewriting all the great info out there! There are also inkjet specific email groups around at YahooGroups and other places which you can join and read archives and get specific answers from users of the same device.
Stephen Marsh.