Simple Fix: GIMP Not Erasing To Transparency

Erasing to transparency with GIMP

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.

Just a heads up — there’s a video explanation below if you prefer watching over reading:

Update 4/6/2020: Added another possible reason, however it’s not addressed in the video.

Eraser Not Erasing To Transparency

If your eraser isn’t erasing to transparency in GIMP, it can be for any of the following reasons…

Let’s explore these reasons further.

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.

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.

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

Eraser Hardness

In GIMP version 2.10 and later, there’s now a Hardness option in the Eraser tool menu. Having it set at anything less than 100 will reduce the size of the space your eraser erases, so make sure you have it set to 100.

GIMP eraser hardness

Anti Erase

Another reason why your eraser may not be erasing to transparency is because you have anti erase enabled in the tool settings. This will prevent the eraser from doing its job.

Anti erase

With the eraser tool selected, navigate to the bottom left-hand side of your screen to the tool settings. At the very bottom of the list you should see Anti erase (Alt). Make sure it is not enabled. If it is, that’s probably why your eraser isn’t working the way you expect.

Lock Pixels

In the layers menu, just above the layers’ names, check to make sure you don’t have the Lock Pixels icon enabled. It is represented by a little paintbrush icon.

Lock pixels

If that feature is enabled go ahead and click it to deactivate it, otherwise you won’t be able to erase to transparent.

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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51 thoughts on “Simple Fix: GIMP Not Erasing To Transparency

  1. OK, it’s a miracle. I read another post of yours and tried right click then add alpha channel. I swear nothing changed (there was already an alpha channel) but suddenly I could delete. So that’s another suggestion for everyone. Even if it looks like an alpha channel is there, try adding another.

  2. I am so sad. Nothing is working. I am trying to delete the background from an image. I have done this with other images no problem. (the eraser is also not working.) Maybe I screwed something up when I was adjusting colors etc.?
    (I also can’t figure out how to post a screeshot)
    🙁

  3. Thank u Nick, very helpful article.
    One more problem. I u create a new layer then in has an alpha layer by default. If u import a jpg by: File-Open as New Layer, then this new layer does not have an alpha channel, it has to be added. Took me a while to figure that out.

    1. Yes, that is because JPEGs do not support transparency, so it won’t have an alpha channel by default.

  4. Thank you. Setting the layer to Alpha Channel fix my issue when deleted a selection and instead of going transparent, the currently selected color was applied.

  5. If still any does not work.

    Do a “deselect” of the area you have previously made.

    You can use Ctrl+Shift+A or Select None

    This is why the restart works because after restart there is no selected area.

    Happened to me and figured it out. Something that also happens in Photoshop.

  6. I’ve been researching my eraser issue with no luck for a while. I’m on Mac OS 10.15.7 (Catalina), GIMP 2.10.14.

    I have a file with two layers. One layer has the drawn parts I’m trying to erase, the other is a layer with color so I can see my black drawing against something other than transparency. They both have alpha channels. My opacity for the eraser is set at 100% as is the hardness. The anti erase setting is unchecked. No layer has pixels or alpha channels locked.

    My eraser was working on this file recently. What I was doing was selecting a path so that I could correct some curved lines. I would hit enter to select the closed path, then leave it as it is or invert it depending on which side of the line/s I wanted to erase from. Switch to the eraser, and … erase! Except that’s no longer working. It doesn’t even work on the other side of my path line just in case I was silly and trying to erase the wrong area. If I try this and then go to the edit menu to look at what action was last done and can be undone, it doesn’t matter how many times I’ve clicked the mouse to use the erase, it says the last action that can be undone was “select to path.”

    I don’t understand all tool options for eraser. I have changed the size to no affect. The aspect ratio and angle are set to 0. Spacing is set to 10. Force is 50. Dynamics options is checked but none of the other check boxes are. The eraser mode is greyed out but says Normal.

    Thoughts? Corrupted file? Corrupted version of Gimp? Pebkac?

  7. Nick, you hit it out of the park. I was misunderstanding the Opacity range & I couldn’t erase unwanted background.
    Thank you ever so much. I’ve got to save your URL against future need.

  8. make sure you have alpha channel selected (by that i mean toggled on) in the Channels tab (next to Layers), otherwise you won’t be able to work with transparency even if you did everything else in this article

  9. I’ve checked everything listed here and could find no reason it would not erase. I was trying to erase in a masked layer to colorize in an overlay. Nothing worked until I closed the program and restarted it. When I loaded the .xcf file I was working on it erased as expected. Must be some bug. Using Gimp 2.8.22 in linux mint.

    1. Yep, this happened to me too. I worked my way down the list to no avail and then read your comment. Thank you so much!!

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