02-19-2020, 06:11 PM
(02-17-2020, 03:22 PM)Ofnuts Wrote: In my experiments Save Layers/No save layers made no difference, but of course I had a singe layer.
I've been running GIMP in portable fashion stored on thumb drives. This allows moving up to new version without making any change to old version. GIMP does use lots of storage but thumb drive makes that cheap.
Have now added GIMP 2.10.14 to said thumb drive. It turns out that the issue that provoked this post (i.e., alpha channel mysteriously added by export) does NOT occur on 2.10.14 but does on 2.10.12 and in fact it appears as though Save Layer cannot be selected in the case when no layers have been added. I haven't gone back to see what other earlier versions of GIMP may also have this defect.
Have now also learned a bit more about multi-layer editing in GIMP. The things I've been doing did NOT seem to involve use of the alpha channel. Therefore, this is something I did NOT pay much attention to. However, it now does seem, to me, that alpha channel is something that goes along with many of the features that motivate use of multiple channels even if this is something for which I was unaware. As a result, it now appears to me that producing the kind of tif file that I've been trying to create from a multi-layer image can be done by selecting Flatten Image from the Layer Dialogue. Since I want the multiple layers retained, for future possible changes, in the xcf file it looks like I need to be real careful to avoid erroneously saving the flattened image.
Anyway this seems to solve both the storage consumption problem associated with unnecessary alpha channel as well as the compatibility issue that was forcing me to reprocess tif files created by GIMP with other software.
Many thanks to contributors who guided me toward these discoveries and please correct any apparent misunderstanding on my part.