Brush Oppacity issue when painting under selection mask

Hi everyone,

I have a brush oppacity issue as follows (Krita v5.0).

  • painted a mushroom
  • created a selection mask by clicking “CTRL + Left Mouse” on the painting
  • inserted a new layer and now trying to paint the mushroom within the selection (see also Screenshot #1)

Painting within the selection works fine, however, the brush oppacitiy seems not to be consistent (see screenshot #2). Painting over an already painted area increases the oppacitiy (which it shouldnt as I am using the Basic-1 brush which works at full oppacity).
Oppacitiy of brush as well as layer is set to 100%, Layer mode is normal.

When painting not under selection mask the oppacitiy is fine, it just appears when painting under the selection mask.

Any ideas how to solve this?


Hello and welcome to the forum,

I had a suspicion and upon testing I believe it is what is happening to you.
You painted the mushroom with a brush with Opacity lower than 100%. It is kind of non intuitive and I don’t know why, but the Selection mask makes a ‘semi opaque’ selection in such cases.
You can verify this by hiding your paint layers and clicking on the Selection mask Layer, you will see (if I’m right) that your mushroom is not fully white, but has a pinkish hue.


1 Like

@Tris Hello and welcome to the forum :slight_smile:

Which selection tool were you using at the time?
I don’t think you need to hold the Ctrl key, just a left click should be enough to make the selection.

@Daishishi Only the Contiguous Selection tool should give greyscale components of the selection mask and then it needs there to be different colours (or different opacities of the same colour) present.
I can’t get a greyscale component on the selection mask with a single colour that is less than 100% opacity.
How did you do that?

@Tris You don’t show the entire image. The selection extends below the screenshot area you’ve posted.
Are there other colours below that? Can you show a full screenshot?
If there are, and you’ve used the Contiguous Selection tool then that could explain the situation.
You can prevent that by disabling the ‘Anti-aliasing’ option in the Tool Options docker.

1 Like

Hello @AhabGreybeard,

First about the need of using Ctrl to make a selection. It is an alternative method when clicking in the thumbnail of the layer of your choice, in the layer stack docker.
I’m fairly certain is analogous to Right clicking on the layer and choosing Select Opaque (Replace), at least it yields the same result as it.

Now how I did what I did. First my general spec for clarity: I’m using Linux Pop! OS 21.10, Krita 5.0.2 appimage.

  1. I create a normal document (A4 300dpi) with default sRGB colorspace.
  2. I selected the brush b) Basic-1 and lowered the Opacity to 70%.
  3. I painted a ‘blob’ using the default Black color, then a separate ‘blob’ using red
  4. After this without changing the tool I was in (Brush Tool), I Ctrl clicked in the layer thumbnail in the layer stack.
  5. Then clicking in the Selection Mask layer the ‘blobs’ were semi Opaque.


1 Like

Hello @Daishishi,

Select Opaque … I always forget about that one :slight_smile:

Thank you.

First of all: thank you for the warm welcome :).

@Daishishi You were right, somehow I must have missed the low oppacitiy of my initial mushroom painting layer. Oh my, such a simple solution I was not able to figure out. Thanks a million.

@AhabGreybeard Also a big thank you for your support.


Good to know it solved your issue,

Others tips that may aid your workflow is using the Alpha lock, the Checkerboard icon on the Layer Docker.
Using it on a copy (or on the original) layer you want to be the ‘base’ of your drawing. In your example, making a copy of the Mushroom Painting Layer and enabling the Alpha Lock would make you paint only on its Opaque portions.

You can also look on how to use Clipping Groups. The Krita Manual it is more adequate (and better illustrated) to show how to use it.
Clipping Group Tutorial - Krita Manual

IMPORTANT: Both these method has the same ‘issue’ as the Select Opaque. A 50% opacity stroke will only be painted to at most 50% opacity, even with a 100% Opacity brush. However is good if you want to redraw or recolor a portion of your drawing without losing the opacity of the strokes.



Thanks again :slight_smile:

I was also checking out the Alpha Lock previously but encountered same oppacitiy issue - now I know why :innocent:


This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.