Media tab

This tab lets you specify the film type and the color mask values (if you want to lock the orange mask color for negatives).

Slide/Negative/B/W vendor/brand/type

Use these options to set up the film type for various settings for the "Device|Media type" option.

Auto mask

Use this option to automatically compute the color mask value for each scan. The color mask is the maximum color of a piece of film or reflective image. This maximum value is used to set the film color for 100negatives, and the film color for 100reflective prints.

An advanced technique is to scan a piece of unexposed negative or overexposed slide and then turn off the "Auto mask" option. This will lock the value for the color mask so you can have a consistent value for an entire roll of film. Otherwise, scanning an overexposed negative or underexposed slide may automatically compute a value that's too small, resulting in subtle color shifts.

Mask red/green/blue

This option lets you manually enter values for the color mask. This is primarily useful if you're scanning a series of negatives or slides from the same roll of film.