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Can you "paint" in transparent

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When you create a new layer over an existing one you can paint over the underlying image. Is there a way to paint transparency over the underlying image?

To explain. I have a drawing of a pixel man, and I want to produce more images of him with different gestures. To do this I want to create a new layer over him and change just the bits I need by overdrawing, but I need to "erase" the bits from the underlying image that I don't want (i.e. paint transparency over it!). Then when it gets flattened it will just have the resultant image.

I've found the layering works better than copying the original as if I make an error then I can just normal erase to see the underlying image again. So there's a difference between erase and painting transparency, if you see what I mean.

Thanks for any advice :)

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It is possible to set your color to zero Alpha - Transparency, and Overwrite blending.

Then you could "paint transparency" onto pixels in the active working layer.

It is not something that could then be erased to bring the image back.


The Undo function could be used to fix errors.


Making duplicate layers of the original as spares would make it easy to retrace steps.

If you can post an example image and explain a bit more specifically

what you are doing, it might lead to some helpful suggestions.

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To try and illustrate what I mean imagine the following 4-pixel image. In layer 1 I put 3 red pixels. Layer 2 over that has just 1 blue pixel. When merged down the resultant image has 2 red and 1 blue in it as shown below.

What I what to do is (in layer 2) put a transparent pixel that overwrites the pixel below (which isn't transparent in the traditional sense) so that when merged down the result only has 1 red and 1 blue in it.


Does that make more sense? I understand that these may seem slightly odd (and I have a hard time getting my own head around it) - but I figure I can overwrite in a colour so why can't I overwrite transparency

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Okay. You want to be able to do Merge with Overwrite Blend mode.

Not possible.

The closest to a work-around, would be to choose a background color

that won't be in the final image. Use that color in place of alpha,

then eliminate that color as a final step in the flattened image.

So, if you chose green as that temporary background color,

your set-up would be:

Layer Two . . . Duplicate of Layer One

Layer One . . .Original Image Object

Layer Zero . . Background - All green

You would work on Layer Two. (Top layer)

If you paint a green pixel it would appear as having been erased,

because it now would match the background.

If you then erase that green pixel, it creates a clear spot in Layer Two,

that allows the original image on Layer One to show through.

So, that way, erasing a change you have made would

bring back the original appearance automatically.

After flattening your completed edit, get rid of the green

using the Magic Wand/Delete or Grim Color Reaper plugin.

Edited by Sarkut
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Ok - thanks :) I was using a separate colour and then removing after merging - didn't think to make a layer below with that colour which is obvious now you suggest it!

I know the Gimp has a "colour to alpha" feature that i've found useful (sadly the gimp is just way to complex for me usually!) - do you know if there's a Paint plugin that does that?

cheers again for the help

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