This tab is used to control the colors of the preview and scan. It lets you specify the film type, the film color, the image brightness, the color balancing, the black and white points and the color space.
The Monitor color space is the color space used to display images in the Preview and Scan tabs. The File color space is used when writing images to JPEG, TIFF and Index files.
Note that if you use the Apple RGB, ColorMatch RGB or ProPhoto RGB color space, the image gamma will be 1.8. If you use any other color space, the image gamma will be 2.2.
You can change the image gamma by using the "Color|Image brightness" option. This is a multiplier of the gamma of the color space chosen.
If you're using Photoshop, you'll probably also want to enable writing the ICC profile to the TIFF and/or JPEG file by using the TIFF profile and/or JPEG profile option in the Files tab.
The "Device RGB" color space doesn't embed any ICC profile into the TIFF or JPEG files, and outputs images in the color space of the device. The "Device RGB" option is only useful when "Device|Media type" is set to "Image".