Photivo

Photivo is a free and open source photo processor. It handles your RAW files as well as your bitmap files in a non-destructive 16 bit processing pipe with gimp workflow integration and batch mode.

Features

16-bit internal processing, color managed with LCMS2.
Gimp workflow integration (import and export)
Works with RAWs and Bitmaps (8 bit bitmaps are transformed and processed with 16 bit, which usually gives better results).
CA correction, Green equilibration, line denoise, badpixel reduction, wavelet denoise, median filters on RAW data.
Perspective correction (tilt and turn)
Demosaicing: Bilinear, VNG, VNG4, PPG, AHD, DCB, mod. AHD, VCD, LMMSE, AMaZE (needs work!).
RGB, R, G, B, L*, a*, b*, Texture, Detail, Hue, Saturation, L* by Hue, Base curve.
Tonemapping (Reinhard 05 (RGB Brighten), Fattal et al. (Dynamic range compress)).
Several local contrast filters (HiRaLoAm (Local contrast), texture contrast, local contrast stretch).
Sharpen (Edge avoiding wavlets, USM, Highpass, Inverse diffusion, Wiener filter, Gradient sharpen).
Denoise, seperately on Luminance and Color (Edge avoiding wavlets, GreyCStoration, Wavelet, Masked bilateral, Pyramid).
Adaptive saturation.
Film grain simulation.
Black and white conversion.
(Split) Toning.
Cross processing.
Gradual overlay (like Cokin filters).
Vignetting.
Softglow / Orton.
Texture overlay (external texture)
Batch mode.