Hello -- I've been posting around trying to help get to the bottom of various problems with tiff formats in higher bit depths -- perhaps you saw my posts on gimp-user-list. I'm told that the .tif format is a bit of a mess, but in case it's useful, I thought I'd post here (apologies for the pseudo-cross-posting -- not sure where to go for this -- if I should stop here and just file a bug report, let me know):

Here is a .zip file of various .tif files, most of which don't open properly for me in GIMP (linux or windows): http://caseyconnor.org/pub/image/smallexample2.zip

Some of these can be "recovered" by opening them (they open as all-white) and then changing to an integer precision. Some can't. All of them open properly in Luminance HDR, which seems bullet-proof for high-bit-depth tifs. Everything else (gwenview, hugin, darktable, etc) seems to have various issues with this or that format.

Files in the zip:

original.tif -- 16bit integer -- original image exported from Canon Digital Photo Professional
original2.tif -- a copy of original.tif aligned000?.tif - the result of "align_image_stack --gpu -C -a aligned original*.tif
aligned_then_gmic.tif -- the result of gmic -median_files aligned\*.tif -o aligned_then_gmic.tif
hugin_output.tif -- the result from hugin of running a simple rectilinear stitch on aligned_then_gmic.tif aligned_then_gmic.pto -- the pto used with hugin to do that other_example.tif -- another strangely-behaving .tif file in case it's useful

I can come up with workarounds on this stuff, I was just hoping that these various tools could possibly be brought in line with each other -- seems like they should be friends. :-)

My test setup: Kubuntu 16.10, otto-kesselgulasch gimp 2944dbd688. (Also happens with pixls.us gimps. Happens on linux and windows.) G'MIC 2.0.0. pre-release #013117. align_image_stack version 2016.3.0.85fedd083c55

Thanks!

-c