"Most photo printers cannot print the full gamut of srgb, so there is no sense sending a photo to a printer in regular Adobe RGB format."
Actually, both sRGB and Adobe RGB are "working" color spaces -- the range of colors you work with -- and are device independent.
No printer's color space matches either the sRGB or Adobe RGB color space. Each printer has a unique color space that depends on the idiosyncrasies of the printer, the ink type (dye vs. pigment) and manufacturer (OEM vs. third-party), and the paper printed on.
Many manufacturers default to the lowest common denominator -- that is, the smallest color space (sRGB) -- in order not to exceed the capabilities of non-color-managed software, such as Adobe Elements and most Web browsers. If you're displaying your photos in a Web browser, or on a monitor connected to a PC (which is less color aware than Macs), or printing with Adobe Elements, then you should follow the strategy of using the lowest common denominator. If you're printing with Adobe Photoshop or other color-managed software, you should print with the actual, unique color space that your printer uses. Your printer's ICC profile for various papers probably came on the CD packed with the printer, or you can download it from the printer manufacturer's Web site.
Here is color space diagram for the Epson 2200 printer. Note that the gamut of this printer exceeds sRGB (white box), but is almost completely contained within Adobe RGB (black box). If you set your camera to capture sRGB, or you work in sRGB, you will lose all the color information outside the white box, including the deep cyan and green colors that
could have been printed if the camera had been set to capture Adobe RGB
and you had maintained the Adobe RGB working space until Photoshop converted it to the printer's unique color space for printing.
Dry Creek Photo has an excellent
tutorial on color spaces. They also have
downloadable ICC profiles for most of the commercial digital printers at Costco, Wal-Mart, etc. --Randy