I've begun to need an Alpha channel for certain images I'm working with and had a few questions as I'm not entirely familiar with Gimp. First off, I'm working with .png's, and I add the Alpha channel via: <Image>->Image->Alpha->Add Alpha To Image Now, with the eraser tool, I can shade out regions I need to be invisible. Now, my question is, I can't seem to restore pixels or such without an undo operation. I'd imagine it still exists so how do I restore the Alpha value to maximum? Also, is there a way to switch views from that with Alpha (where erasing removes Alpha) and that without Alpha (such that Alpha is still there, I'm just not concerned with seeing it)? Thanks in advance.

You should be able to 'restore' alpha if you clone stamp the original alpha image over your edited one. The erfaser tool erases alpha like everything else so there's no way back without an undo. You can still try to bump contrast/light if you really need to..

Quote:Original post by Rockin
You should be able to 'restore' alpha if you clone stamp the original alpha image over your edited one. The erfaser tool erases alpha like everything else so there's no way back without an undo. You can still try to bump contrast/light if you really need to..

Ok, thanks.

Is there a way to only delete/erase the alpha values?

It would seem you basically have to draw your image and then add alpha afterwards. I'd like to be able to switch back and forth as necessary.

I know that the rgb values are retained when adding and using an alpha channel as I can display the images with alpha disabled and the original colors show through the invisible areas. It would be convenient to handle it as something of a layered system where I could use alpha and rgb as independent of each other.

You can right click on the image and select Layer->Mask->Add layer mask to add a separate mask layer to the image. This layer mask will show up adjacent to the selected layer in the Layers,Channels and Paths dialog, and can be selected and edited at will. You can draw in this layer using greyscale for various shades of alpha; when finished, right click the image and select Layer->Mask->Apply layer mask to apply the layer mask to the alpha channel.

Also, once you have added an alpha channel to an image, you can click to the Channels tab of the Layers, Channels and Paths dialog, deselect the R,G and B layers and select the Alpha layer in order to edit directly into the alpha channel. Standard paint tools apply here, draw in grey shades for varying levels of alpha.

Awesome, that sounds as if it's exactly what I'm looking for. Thank you very much for your time!