alfakanal

Alfakanal, or alpha channel, is an additional channel in digital color images that stores per-pixel transparency information. In images with RGB channels, the alfakanal provides an opacity value for each pixel, enabling compositing and various transparency effects without altering the color data.

Typical data representation uses 8 bits per channel (0–255) for the alpha channel, yielding 256 levels of opacity. Higher-dynamic-range and professional workflows may use 16-bit or 32-bit floating-point alpha, and some formats store premultiplied alpha.

Commonly used in formats such as PNG, TIFF, WebP, and AVIF, alfakanal allows images to be layered over others or saved with transparent backgrounds. JPEG typically does not support an alpha channel; GIF provides a binary transparency option but not a full alpha channel. Some formats encode alpha as a separate channel for masks.

In image processing and computer graphics, alpha blending combines foreground and background pixels using the alpha value. Premultiplied alpha stores color components already multiplied by alpha, which can improve performance and reduce artifacts during compositing but requires careful handling when editing.

Applications include graphic design, video effects, 3D rendering, and web graphics. Proper management of alfakanal involves color space and gamma considerations to avoid halos around edges and to ensure accurate translucency in different viewing conditions.