I'll only reply to the question in the topic, repeating quite a bit of the information I put in a write up two weeks ago: http://gimp.1065349.n5.nabble.com/GIMP-GEGL-storage-precision-and-color-management-td34899.html
When operating in 8bit precision is that a GEGL powered GIMP assumes that 8bit precision data is stored with sRGB gamma (this will probably be changed to apply to 16bit integer as well), data with higher bit-depths are stored with a linear gamma ramp in the layer buffers. The working space of the layer modes currently used by GIMP are implemented with sRGB gamma based compositing, thus for higher bit-depth data - we must convert from linear to the sRGB working space - perhaps go back to linear for some other operation, and in most cases we convert back to 8bit sRGB for display (with proper color management we'd go from higher bit-depth to the displays ICC profile or similar). All these legacy 8bit layer modes are scheduled for replacement with operations working in linear light (linear gamma) - at that stage a lot of conversions back and forth (in floating point) will be avoided. Importing 8bit or 16bit images that do not contain sRGB data - should result in precision promotion to probably 32bit floating point, where the data can be well represented ... pending a _potential_ conversion back to the source ICC profile. Note that babl's built in floating point representations have unbounded gamuts thus can represent all of sRGB / ProRGB / AdobeRGB and data with other 8bit profiles. Using the sRGB for 8bit and 16bit integer precisions means that (web destined) JPG and 8bit/16bit PNGs without associated profiles should be possible to directly manipulate. /Ø _______________________________________________ gimp-developer-list mailing list gimp-developer-list@gnome.org https://mail.gnome.org/mailman/listinfo/gimp-developer-list
