Grass Valley EDIUS Pro v.7.4 Reference Manual - Manual (Page 462)

Chapter 12 Appendix — Effects List
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[Linear Light]
Increases the brightness of parts that are bright in the foreground, and lowers the brightness of parts that are dark in the foreground.
[Multiply]
Multiplies the colors and so makes the image darker.
[Addition]
Adds the colors and so makes the image brighter.
[Difference]
Displays colors that have been converted into an absolute value from the difference between the background and foreground.