Black -> transparent

Ok so I'm trying to do this:

And I already found a plugin called "Eliminate black" for PSP and it did that, but the result was this:

So I thought that that's the best result I can get 'cause I didn't find anything else with google and thought that it's pointless to ask about it anymore. BUT then I remembered that you can do this with PSP. You just can't choose "transparent" as the "desired color" so it doesn't help :/

But the question is: does anyone know how I could do this better than with that "Eliminate black" plugin?

I know this must be possible somehow :S I have seen this being done. For example Habbo Hotel uses this kind of filter. I don't know if it's build-in filter in shockwave, but at least it works just as I would want to, just as I explained above. Does anyone have any ideas?

well I know in adobe after effects you could use a color key and set the key color to black. I'm guessing there would be something similar in other programs too, I'd look around for a color key plugin or something.

Ummm I'm not sure 'cause I don't use the same program as you… but Colour to Alpha?

Reaper

Awesome! It worked with Gimp. The result is just as my example in the original post. See:

The right side one is made from the left side one with "Color to alpha".

Thanks reaper!