Kodak i4600 Supplementary Manual page 9

Threshold (Brightness) — this option is available when you select
Fixed Processing or Adaptive Thresholding (ATP). This option
allows you to change the black and white image to be darker or lighter.
The higher the threshold value, the darker the image. Use the slider to
select a value from 0 to 255. The default is 90.
Threshold: 50 Threshold: 127
Contrast ⎯ adjusts how much of the faint detail you want to see in the
output image. The higher the contrast value, the more faint lines will be
shown in the image. The lower the contrast value, the clearer (or less
detailed) the output image will be. If contrast is set too high, you may
get lines or black areas in your output image that you do not want. If the
contrast is set too low, some letters or lines may not show in the output
image. Select a contrast value from -50 to 50. The default is 50.
8 A-61654/ISIS December 2009