GIMP: Using Channels Independently

Question

I need to use GIMP instead of Photoshop, but I have a problem doing some things with transparency:

I explain: I manipulate some tga files that have 4 channels, rgb and alpha.

Using Photoshop I'm able to draw into the 4 channels independently, and the alpha is used like the other channel: here is a shot:

If I try to open the same tga image (32 bits compressed) with gimp:

you can see that the 3 channels rgb are masked with the alpha channel, and the image is uneditable...

Any suggestions?

Thanks

Answer 1

In your Photoshop screenshot, the alpha channel is not marked as visible. In the GIMP screenshot it is.

Try clicking the eye icon next to the alpha channel in the channels dialog. That should hide the alpha channel, allowing you to see and edit the other channels even in areas where the alpha channel is fully transparent.