IamSam
I'm getting an invalid file attachment....
maggie2
Zipping the .abr will work though.
I don't think you need to upload the brush though to be honest....its evident from your image that there is transparency in the brush.
If you look at the larger 792px size brush you'll see that the edges of the lines are various shades of grey. This could be due to feathering or anti-aliasing when you made the original brush preset but whatever, when you make that brush smaller those 'grey' bits still have to be accounted for, despite the drastically reduced number of pixels that make up the smaller brush size.
As you make the brush size smaller those 'lines' get thinner, to a point where in order to still accommodate the 'grey' bits some of the inner 'black' bits get squeezed out...there just aren't enough pixels to show every shade of colour in the line.....hence the outer 'grey' pixels take precedence and as a whole the brush becomes more 'grey'.
Making the brush smaller is effectively 'transforming' the image used for the shape of the brush, reducing the amount of pixels used for it.....it stands to reason that any reduction in pixels is going to reduce the number of different colours that can be used.
Depending on how you intend to use this brush you can 'duplicate' the layer to reinforce the 'grey' pixels....if you duplicate enough times eventually all the 'grey' pixels will become black.
Be warned though that this does rely heavily on how you intend to use the brush.....it may not be possible in your workflow to duplicate the layers and if you do you may need around 8 duplicates to make everything black.
50% transparency added to 50% transparency does not equal 100% transpareny...its around 75%.
Add another 50% to that 75% and you get around 83%.....8 duplicates should get you as near to 100% as makes no odds.
I mention 'duplicating' the layer as hitting the exact same place with the brush 8 times could lead to missalignment......duplicating removes all alignment error.
Regards.
MrTom.