Erase problems

[Robert Foster]

Hi I am new to this forum but not new to Gimp.
  I do a lot of blending photos and recently I am having issue with erasing. All my older image projects still work fine, but when every I input newer photos as an original project or on top of an older project. Well they won't erase properly. What is happing is erase seems to be getting replaced by a color and this has completely stopped my work flow.

Mac/OS Big Sur 11.4
Gimp 2.10

[Ofnuts]

Is there an alpha channel on the layer where you erase (the names of layers without an alpha channel appear in boldface in the layers list).

   

[PixLab]

Edit > Preferences > Image Import & Export > Tick -> "Add an alpha channel to imported image"
No more problem with transparency when you erase on new imported images

   

[Robert Foster]

-Ofnuts, when I click on "Channels" my basic is Red, Green, Blue, Alpha.

-PixLab, I did what you said and nothing changed.

I desperation I totally deleted Gimp and reloaded it, no change.

[Ofnuts]

(07-29-2021, 07:55 PM)Robert Foster Wrote: -Ofnuts, when I click on "Channels" my basic is Red, Green, Blue, Alpha.

-PixLab, I did what you said and nothing changed.

 I desperation I totally deleted Gimp and reloaded it, no change.

That doesn't really answer the question. The list to look is Layers, not Channels. You can also see if Layer ➤ Transparency ➤ Add alpha channel is greyed/disabled, which means that the active layer already has one.

Also deinstaling-reinstalling Gimp rarely cures things since your Gimp profile is kept across reinstallations. See https://www.gimp.org/tutorials/GIMPProfile/

Otherwise, can you post a screenshot showing:

1. the titlebar
   
2. the layers list
   
3. the Tool options dialog for the Eraser
   

[PixLab]

(07-29-2021, 07:55 PM)Robert Foster Wrote: -PixLab, I did what you said and nothing changed.

If you reloaded a .xcf, it wont change anything (see ofnuts solution - right click on the faulty layer in the layers dock dialog - add alpha channel to solve the problem with older project)
But any new imported image will have an alpha channel (no more "Bold" writing in the layer dock as they will have the transparency channel as well)

[Robert Foster]

got it