Alpha channel

English

Etymology

Coined by Template:W and Template:W in the 1970s. Smith writes: "We called it that because of the classic linear interpolation formula $\alpha A+(1-\alpha )B$ that uses the Greek letter $\alpha$ (alpha) to control the amount of interpolation between, in this case, two images A and B". That is, when compositing image A atop image B, the value of $\alpha$ in the formula is A's alpha channel.

Noun

1. Template:Lb A numerical value specifying a level of translucency to be applied to a colour.

Translations

• Finnish: Template:T
• Portuguese: Template:T