How do you change the opacity of a Photoshop tool (e.g. the brush or the paint bucket) to something other than an integer 1% to 100%, such as 0% or 0.5% or 99.5%?
When I try entering these numbers manually an error window pops up, saying it's invalid:
It's my understanding that in many images (8-bit per channel PNGs at least) the alpha channel has a range or 0-255, just like the red, green, and blue channels. So more than half of those alpha values are impossible to reach with an integer from 1-100 (without complicated compositing of multiple transparent layers). After all, Photoshop has 0-255 sliders for RGB, why not for opacity? Or, if so, where can I enable this feature?
I'm using Adobe Photoshop CC 2018 (which has no tag it appears).