Brush paints out of selection

[Lusco Fusco]

Ok, here is something that escapes me and, although  I had many turns on it,  I can not find the solution.

It is assumed that with an active selection, the brush should only paint within the selection.  Well, I load two images, add a mask,  invert it to  black.  I select the lower image,  make a selection based on luminosity,  return to the mask, I paint on it with a white brush at 100% opacity (not alfa protect selected) ... and:

  1.- Despite having opacity in 100%, I have to paint several times in the same place to get an absolute white that totally reveals the image.

  2.- When I am on the edges of the selection, the brush also paints OUT of the selection ( altough although with lower opacity (!?) )

  It must be something very obvious that I am overlooking, this process I have done a thousand times in GIMP without problem.

Please, if anyone has any ideas or suggestions, I would greatly appreciate it.

[Alfred]

1. Your screenshot shows that you have the hardness set to 50%.

2. It sounds as though the selection is feathered. I think the ‘marching ants’ outline only shows areas which are at least 50% selected.

[Lusco Fusco]

Thank you alfred, but hardness is not the problem, attached a screenshot with hatrdness at 100%, same effect...

Also, how could i see if a luminosity based selection is feathered, and if so, avoid it?

Thanks again

[toltec]

1 hour ago, Lusco Fusco said:

Thank you alfred, but hardness is not the problem, attached a screenshot with hatrdness at 100%, same effect...

Also, how could i see if a luminosity based selection is feathered, and if so, avoid it

A luminosity mask selection is not the same as a pixel selection. A pixel selection makes hard edges.

Feathered is not the correct term, A luminosity selection will always be of a varied density (like varied opacity). Only 100% white will be solid selection. Everything else will be a partial selection (or partial density) from 100% for white , to 50%  selection density for mid grey down to 0% selection density for black. Obviously depending on the luminosity throughout the image.

It is the partial selection density throughout the image that that is causing your problem.

You can press Q (for Quick Mask) to see how dense the selection is.

[Lusco Fusco]

17 hours ago, toltec said:

A luminosity mask selection is not the same as a pixel selection. A pixel selection makes hard edges.

Feathered is not the correct term, A luminosity selection will always be of a varied density (like varied opacity). Only 100% white will be solid selection. Everything else will be a partial selection (or partial density) from 100% for white , to 50%  selection density for mid grey down to 0% selection density for black. Obviously depending on the luminosity throughout the image.

It is the partial selection density throughout the image that that is causing your problem.

You can press Q (for Quick Mask) to see how dense the selection is.

Thank you! This clarifies the matter, as one could not expect less from the wisdom of a Toltec ...

Now I just have to move my assemblage point to a position that allows me to find a method to use these luminosity masks.

[R C-R]

2 hours ago, Lusco Fusco said:

This clarifies the matter, as one could not expect less from the wisdom of a Toltec ...

"a Toltec"??? Surely you do not mean to imply there is more than one!?! I do not think the world is ready for that. 

[Lusco Fusco]

2 hours ago, R C-R said:

"a Toltec"??? Surely you do not mean to imply there is more than one!?! I do not think the world is ready for that. 

https://en.wikipedia.org/wiki/Toltec_(Castaneda)