Hello, I've been running into an issue with the OIIO libRaw support and wanted to see if anyone else had run into the same problem and found a workaround.
The issue Raw files read and developed by OIIO using libRaw are automatically brightened. The potential cause tl;dr The RawInput::open method doesn't set the 'no_auto_bright' flag https://github.com/OpenImageIO/oiio/blob/master/src/raw.imageio/rawinput.cpp#L130 like dcraw does when using either the '-4' flag or the '-W' flag. https://github.com/LibRaw/LibRaw/blob/master/samples/dcraw_emu.cpp#L337 https://www.cybercom.net/~dcoffin/dcraw/dcraw.c - line 9963 or 9965 Context If you use dcraw, or libRaw's dcraw_emu, to convert raw images to Tiff, and you want to produce linear 16 bit data for your exposures, the '-4' flag is often used. That is a shorthand for the flags '-6 -W -g 1 1'. '-6' set up 16 bit data processing. '-g 1 1' sets the gammas to 1.0, 1.0. '-W' turns off dcraw's 'auto_bright' functionality. The last flag is especially important if you want to merge exposures or otherwise treat your data as a more exact measurement of the world. Suggestion Add the line: m_processor.imgdata.params.no_auto_bright = 1; around line 137 of rawinput.cpp https://github.com/OpenImageIO/oiio/blob/master/src/raw.imageio/rawinput.cpp#L137 Open question For general OIIO usage, is there a good reason to be able to turn 'auto_bright' on? Will be testing that out this weekend but figured I'd see if there was an alternate approach to solving this problem. Thanks in advance for your help, HP
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