But, it works with RAWs. Is this expected behavior? Thanks.
Hi Peter,
Since nobody else responded sofar...
Not really expected, but somewhat understandable. A Raw file is (usually) in linear gamma, which makes changing 'exposure' after-the-fact relatively simple (just a multiplication factor). Once imagedata has gone through unknown no-linear adjustments, it becomes much harder to adjust 'exposure' or rather brightness. Because also gamma is usually no longer linear, color in pre-processed TIFFs will change with brightness adjustments.
Nevertheless, for small adjustments, I think it would be useful to have a means to synchronize brightness levels of TIFFs. One typically can use the image median value if the scene is the same. For other matching one would have to rely on the EXIF data, but exposure info is not that precise (1/3rd stop interval precision), and the images could have been edited differently since, so overlapping regions need to be found and compared. The changes to the TIFFs would preferably be done after linearization to gamma 1.0 and then back to where they came from, e.g. 2.2 or 1.8, or sRGB slope limited gamma.
Cheers,
Bart
