Erasing to transparency with GIMP

Simple Fix: GIMP Not Erasing To Transparency

Simple Fix: GIMP Not Erasing To Transparency 1024 602 Nick Saporito

Today I’ll be addressing a very common problem many of you run into when using the eraser tool in GIMP. I get asked this question a lot: why isn’t the eraser tool erasing to transparency? Instead, it may be erasing to white, black, or some other color. Let’s diagnose why.

Alpha Channels

The most common reason why the eraser tool isn’t erasing to transparency is because there isn’t an alpha channel added to the layer. An alpha channel is essentially a transparent layer that gets positioned beneath your image (even though there’s no actual layer for it in the layers menu.) Without it, the GIMP eraser will erase to white. With it, it’ll erase to transparency.

The fix for this is quite simple, really — just right-click on the layer you’re trying to erase and select Add Alpha Channel.

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Adding an alpha channel in GIMP

If the selection isn’t grayed out and you can actually click on it, there’s your problem. Click on it and you’re good to go. However, if the selection is grayed out (meaning there’s already an alpha channel added,) then something else has gone wrong. Keep reading to find out.

Eraser Not Erasing

Let’s look at some other typical reasons why you may be having trouble with the eraser tool.

Activate The Proper Layer

This may seem like common knowledge, but it’s a mistake that even I foolishly make once in a while.

The eraser will only work on the layer you have selected, so if you’re furiously trying to erase an image and nothing is happening on your canvas, it’s probably because you have a different layer selected. Double check to make sure you’ve activated the correct later.

Select the proper layer

Selections

If you have an active selection within GIMP at the moment, the eraser is only going to erase whatever is inside of that selection.

Release active selection

To rectify this, go to Select -> None and see if that does the trick.

Eraser Opacity

A less common reason why you may be having trouble erasing your image could be because the eraser opacity is set to 0. Check the Tool Options panel and make sure the Opacity slider is all the way up at 100%.

Check the eraser opacity

While you’re at it, go ahead and check which brush head you’re using with the eraser as well. This is unlikely to be a problem, but it’s possible if you’ve selected a corrupted brush. Try out several just to be sure.

Check the active brush panel

No Luck?

That should cover all bases and fix any problems you may have trying to erase images in GIMP, but if you’ve tried everything listed above and your eraser still isn’t working, leave a comment below with an explanation and/or screenshot and I’ll see what I can do to help you out.

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Nick Saporito

Nick Saporito is a Philadelphia-based graphic designer who specializes in branding-specific design.

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2 comments
  • Matt

    When I erase using 1.00 pixel size (using either “2. Hardness 100” or “1. Pixel” brushes) I have to go over the same spot multiple times to fully erase it, otherwise it only partially erases it. Yet opacity is set to 100%. Do you know why this might be?

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