OK, this has irritated me a long time. When I adjust image position by dragging or nudging it (select all, nudge with keys), there appear transparent area where the image was moved away, So far so good. But when I save TIFF it stays there and does not flatten like nice wellbehaved TIFF should (unless told to have layers). Even worse, there seem to be no way in Acorn to remove this transparency.
In Photoshop 1) there is no transparency in TIF (unless set in save options) and 2) Flatten image command would remove transparency. In Acorn Flatten command seems just to flatten layers but it ignores transparency.
Is it really only way to remove transparency to add white layer behind actual image and flatten that? That slows editing as there may be hundreds of images and workflow should be as quick as possible. And this transparency shows as artifacts down the road when I process further in other batch apps.
Photoshop will save a TIFF with transparency by default, if that image has an alpha channel in it to begin with. If it doesn’t have an alpha channel, then the image will open up as a single “background” layer which is treated differently in PS.
Acorn has no concept of “background” layers (all layers are composited the same), Acorn will add an alpha channel to an image when you add transparency.
I had no idea “flattening” an image in PS also adds a matte to the background!
While there’s no 1:1 mapping with what PS does in Acorn, there is a relatively simple solution today, and that’s to use the Filter ▸ Color Effect ▸ Matte… menu item (or just type “matt” in the Command Bar). It’ll add a white background to your layer and when you save your image, it’ll remove the alpha channel.
I’ll consider it a feature request you’d like “flatten” to remove transparency as well.