(07-10-2021, 09:25 PM)her24gl Wrote: Also, since we're talking about how the file is made, let me ask you something else. When I look at all my other files that I've purchased with transparent backgrounds, has the nice clear subject/image sitting on top of the checkerboard "transparent" layer. When i open her PNG file, it looks like the subject/image is behind the checkerboard transparent layer, if you know what I mean. Is that how Photoshop does it's transparent "backgrounds?" It doesn't make sense to me... if it's laying in front of/over the "image" then it's not the background, right?? LOL. But i digress....
Interesting, it seems that she did not use a layer mask as a primary element to remove the background, but something like "Blend if" or the removal of a "color range" or a method which affect the entire image like a "color to alpha" alike.
If she scanned the doc with a "yellowish" background as scan result, she could have use a method mentioned above as it's an extremely fast method (it takes just few seconds) to remove a cast color and make it transparent. => her method is only a supposition, as a matter of fact without any doc (png or PSD) to share with us, It's all supposition and theory only about her method!
But yellow is opposite of blue, remove yellow you got blue...
Example on a 50% gray layer using a curve in the blue channel (Color > Curves...), instead of being gray when I reduce the blue, image become yellow (remove blue, you got yellow)
as a workaround, try to play with those setting to add yellow and neutralize the blue
But in all case this does NOT answer your printing problem with GIMP,
Your other software are printing without any problem, something is going wrong somewhere, maybe just a setting problem between GIMP and your printer.