I worked with Phel this week getting his workflow nailed down through using ICC profiles for his Sony Artisan and Epson 7600. One concept in question was the use of gamma in display calibration i.e using 1.8 or 2.2, ultimately a 1.8 gamma gave the best screen contrast to print contrast match. It's important to remember gamma is a relationship of tone contrast, a 1.8 gamma will appear flatter whereas a 2.2 gamma will appear to have more contrast. The choice depends more on your viewing environment. A D50 environment will generally like 1.8 more than 2.2 but the choice is purely subjective.