clipping mask is oversensitive

[Титан]

I want to do apply partially transparenty to an image using a mask, but black:tranparency is not 1:1, it's more like x:x³. a tiny amount of black in the mask gives an enormous amount of transparency. How can I fix this and change mask sensivity? I can just overbright the mask for sure, but then I'll see noticables α-channel steps in the image (see attachment), so it's not the solution.

[Титан]

Workaround I find is to increase image α-channel layer bitness to 32 and back to 8 bit when work with clipping mask done

[Титан]

I mean, export as 8-bit or set 8 bit when layer have no mask (it's embedded/applyed/merged). Changing α-channel to 8 bit while mask is active will cause noticable transparency steps

[davescm]

What does it look like when you view against a solid layer? There is a longstanding preview issue which shows banding against the transparency checkerboard. It affects only the preview and not the image. The workaround is to insert a temporary solid layer at the bottom of the workspace.

Dave

[Титан]

I find out that the main problem is not with clipping mask, but with transparency overall. If I try to erace black with ONE percent eraser, it will wipe out like 20% (left). There's a gimp's eracer with 5% in the right for comparison

If I lower the pressure (parametr), photoshop will do strict borders.

It looks like there's how 1 value (out of 255) looks like. It certanly shouldn't looks like 20%. How to fix it?