rasterikuvina

Rasterikuvina is a Finnish term used to refer to raster images, digital images created by a grid of individual colored pixels. Each pixel stores color information, and together they form the visible picture. Raster images are resolution dependent; enlarging beyond the image’s native resolution leads to pixelation where individual pixels become visible.

Common raster formats include PNG, JPEG, GIF, BMP and TIFF. They differ in compression methods, color depth, transparency support and whether they use lossless or lossy encoding. JPEG is widely used for photographs due to efficient lossy compression, while PNG and TIFF offer lossless options and better support for transparency. GIF supports simple animations but is limited in color depth.

Key characteristics of raster images include color depth (for example 8, 16 or 24 bits per pixel), color models such as RGB, and a defined spatial resolution often expressed as dots per inch (DPI) or pixels per inch (PPI). The raster grid determines how detail is represented and how the image scales on different devices.

Advantages of raster images include straightforward rendering on screens and suitability for photorealistic imagery, where fine color variation is important. Disadvantages include quality loss when scaling and the potentially large file sizes for high-detail or high-resolution images, as editing at the pixel level can be destructive.

Rasters are contrasted with vector graphics, which describe images using mathematical shapes and are scalable without quality loss. Raster graphics are commonly used for digital photography, web graphics, textures in graphics pipelines, scanned documents, and raster-based painting programs. Common tools for creating and editing raster images include image editors such as Photoshop, GIMP, and Paint.NET. See also rasterization, bitmap, raster graphics, and vector graphics.