Binarizing a selection

[ateleman]

Hello,

If I have a pixel selection, some regions are fully selected (ie white in the mask channel), some regions are not selected (black), and some regions are partially selected (e.g. if you do Select > Colour Range > Select Reds, and  these regions have greyscale values in the mask layer). The 'marching ants' shows me the region where the pixel selection is above some threshold (50%?). Is there some way to binarize the selection so  that all pixels that are selected above a certain threshold become fully selected (white) and all pixels below that amount become not selected (black) - e.g. leaving in the selection only the regions surrounded by the marching ants and removing the rest from the selection?

Thanks !

[Alfred]

Apply a Threshold adjustment before you make the selection.

[Fixx]

23 hours ago, Alfred said:

Apply a Threshold adjustment before you make the selection.

How would that help? The aim is to threshold the selection mask, not the actual image.

Channel/mask handling is not AP's forte. As far as I can see there is no way to threshold actual selection (as would be the first idea). It should though be possible to make selection a layer that can be thresholded and turn that back to mask. One of the workarounds that are plenty in Affinity environment..

[Alfred]

23 hours ago, Alfred said:

Apply a Threshold adjustment before you make the selection.

 

7 minutes ago, Fixx said:

How would that help? The aim is to threshold the selection mask, not the actual image.

As long as there are no partially transparent pixels, a Threshold adjustment will yield a result where every pixel is either black or white. Making a selection from that will effectively ‘threshold’ the selection, and you can then remove the adjustment and copy the selected region in its original form.

[ateleman]

20 minutes ago, Alfred said:

 

As long as there are no partially transparent pixels, a Threshold adjustment will yield a result where every pixel is either black or white. Making a selection from that will effectively ‘threshold’ the selection, and you can then remove the adjustment and copy the selected region in its original form.

I would like to select based on a sampled color. This can't be done on a thresholded/binarized image... So I think first thresholding and then selecting won't work. I believe I need to first select based on a sampled color, and  then threshold the selection...

[Alfred]

3 minutes ago, ateleman said:

I would like to select based on a sampled color. This can't be done on a thresholded/binarized image... So I think first thresholding and then selecting won't work. I believe I need to first select based on a sampled color, and  then threshold the selection...

Thanks for the clarification. I think you’re correct that my suggested method won’t work for what you want to do, but I’d like to think we’re simply missing a step here!

[walt.farrell]

4 hours ago, Alfred said:

but I’d like to think we’re simply missing a step here!

@Fixx's idea might work.

1. Make the selection.
2. Ctrl/Cmd+J to make a copy of the selected pixels as a new layer
3. Threshold that layer. (Perhaps do a Black/White adjustment first?)
4. Selection from Layer, then delete the layer. This leaves the thresholded selection.

[Alfred]

4 minutes ago, walt.farrell said:

New Layer from Selection, then delete the layer.

I presume you meant to say ‘Selection from Layer’.