Fie on Photoshop: Krita, the Real Photoshop Killer
Two weeks ago we learned why Gimp, even though it is a superior cross-platform image-editing application, is not a "Photoshop Killer." I'm not fond of lurid headlines, but if I were to nominate a "Photoshop Killer" I pick Krita.
Krita isn't really going to kill anything or anyone. What it will do is meet most of the needs of users who want a modern, sophisticated native paint and image-editing application for Linux. It was designed from the ground up for graphics professionals. Unlike Gimp, which is constrained by its elderly 8-bit RGB graphics engine, Krita supports 8- and 16-bit CMYK, 8-, 16-, and 32-bit RGB, 8- and 16-bit YCbCr, 32-bit LMS cone space, 16-bit L*a*b*, 8- and 16-bit grayscale, and it even has a realistic Watercolors simulation. There is a lot of difference in subtlety and accuracy between the various bit ranges. At 8 bits you get 256 values per channel for color images, and at 16 you get 65,536. 32-bit RGB is really 24-bits per channel. The leftover 8 bits are either ignored, or used as a transparent Alpha channel; then it is called RGBA.
If you're shooting photos in RAW mode, modern DSLRs deliver 12- or 14- capture bit depth. To make a long story short, in real life you'll find that 16 bits gives you plenty of elbow room and excellent image quality.
Krita supports the PNG, TIFF, JPEG, Dicom, XCF, PSD, GIF, BMP, XPM, Targa, RGB, and OpenEXR file formats. It can import ICO files. PSD (the Photoshop file format) is only supported up to version 6, because starting with version 7 it became a closed format.