7.38. Grenseverdi for alfa

The Threshold Alpha command converts semi-transparent areas of the active layer into completely transparent or completely opaque areas, based on a threshold you set. It only works on layers which have an alpha channel. If the Lock alpha channel option is checked in the Layers dialog, the filter will have no effect.

7.38.1. Aktivering

  • You can access this command from the menubar through LayerTransparencyThreshold Alpha....

7.38.2. Beskriving av dialogvindauget

Figur 16.121. The «Threshold Alpha» filter options dialog

The «Threshold Alpha» filter options dialog

Presets, Input Type, Blending Options, Preview, Split view
[Notat] Notat

These options are described in Del 2, «Common Features».


The threshold alpha value determines which values will become transparent or opaque. You can set the transparency value to be used by using the slider or by entering a value between 0 and 1 in the input box. All transparency values above this threshold will become opaque and all transparency values below or equal to this threshold will become completely transparent.

[Notat] Notat

Dette valet vil aldri gjere fullstendig gjennomsiktige pikslar (alfa = 0) heilt ugjennomsiktige.

Figur 16.122. Eksempel på alfagrenseverdi

Eksempel på alfagrenseverdi
Ein gjennomsiktig fargeovergang 0-255.
Eksempel på alfagrenseverdi
Grenseverdi sett til 50, 127 og 210.