Opening PhaseOne RAW files (which are TIFs) in RawTherapee and GIMP

I am using Windows 10, GIMP 2.10.38, and RawTherapee 5.10. I have a PhaseOne P65+ digital back that I use with my Contax 645 camera.

My PhaseOne raw files are *.TIF files.

When I try to open one in RawTherapee, it opens as a 220 x 220 pixel image instead of the much larger 4086 x 4086 pixel RAW file. I seem to recall mention that PhaseOne embeds a preview thumbnail in their RAW files, and that seems to be what RawTherapee is opening … a tiny, pixelated, low resolution thumbnail, instead of the robust RAW TIF file.

(SIDE NOTE: When opening a file in GIMP, GIMP does not pass the opening process over to RawTherapee, like it does with I open a DNG raw file, so, like RawTherapee, GIMP is not recognizing these TIF files as RAW files.)

Can anyone please help? I am at my wit’s end!

Thank you,

I might add: I was heavily into photography years ago, and I used Adobe Photoshop CS3. These files all worked then, but now, for some reason, I cannot get CS3 to open them as full files–again, they open as 220 x 220 pixel images. After years of medical setbacks, I’m trying to get back into photography, but I have no idea why everything (GIMP, Darktable, RawTherapee, Photoshop CS3, etc.) is opening these files as small thumbnails. I also would like to avoid having to convert all of these files to DNG format, because, I know, in the past, my software recognized these PhaseOne TIFs as RAW files and opened them as such.

It is opening the thumbnail. Same as with Canon EOS 1Ds and its .TIF

At least darktable works with my 1Ds.

See Dealing With Multiple 'Frames' (Canon 1Ds "TIFF" Raw Images)

Hi @Veracity66! I think what’s happening is RawTherapee sees the .tif extension and tries to open it as a tiff and it succeeds, so it doesn’t bother trying to read it as a raw file. You can rename the files to have a different extension, for example to .iiq which is what some PhaseOne cameras use.

P65+ should be supported by latest darktable 4.8 (the “L” kind of files, not the “S”).

If not, please share a sample.