Mask not fully transparent

[Willemijn0D44]

Dear photoshop-users,

When using a mask, the part that is black in the mask, won't be fully transparent, see image below

As you can see, you can still slightly see the part that is masked. 

I've probably done something wrong, but tried the following:

- when saving as jpg, same happens

- copy and paste ONLY the white part, same thing happens

Feels like I'm going crazy, who helps me out?

Thank you!

[Willemijn0D44]

When erasing the background (in the image, not the mask), the background goes transparent...

Maybe something off with the command-backspace function?

[Willemijn0D44]

Oops no., that's not it either, it just makes it more transparent...

[davescm · Accepted solution]

Check your brush colour. The most common reason for this is that you think you are painting/filling the mask with black but it is not fully black i.e. RGB 0,0,0

Dave

[Willemijn0D44]

Thank you so much! This was it.

Naive me, thinking when selecting a mask, black & white would appear automatically.