Beginner question about transparency

[jdavidroberts]

I have an existing image that has some stuff surrounded by a white background. I would like to switch it to a transparent background. What's the easiest way to do that? I tried setting the alpha to 0 for my Primary Color, then using the Fill tool to fill. But after I do that, if I use the color picker to pick up the color of the white stuff, it looks like the alpha is still 255. So it didn't seem to take. According to the Help, the eraser tool will do what I want, but unless I'm missing something that means I basically have to go individually erase every pixel, and I don't have the stamina for that.

I have a feeling I'm missing a MUCH easier method here, and I was hoping someone could enlighten me. Thanks in advance.

[afcdon]

One plugin to try is Color Replacer - download from here My link

See the following screenshot for the setting you need to change your white background to transparent.

http://i1193.photobucket.com/albums/aa341/afdcon/colorreplacer.png

Edited January 12, 2011 by afcdon

[mountnman]

you could try using the magic wand tool to select the white you want to get rid of (play with the tolerance if it doesnt select all of it, or selects too much) then once you have the area you want transparent selected, just hit the delete button

Edited January 12, 2011 by mountnman

[jdavidroberts]

Thanks you guys rock! The magic wand tool worked perfectly on the first try.

[pdnnoob]

Just as an explanation for what is happening, the paint bucket fills adds whatever the chosen color is to what you selected. It doesn't actually replace what is there which is why you didn't see a change when you used a color with 0 opacity on your picture (you were adding a big literal nothing). To remove color, you have to erase (adjustable) or delete (not adjustable).

[Ego Eram Reputo]

AlphaSpace is another easily used plugin which does the same thing. It also recoginses shadows and deals appropriately with them.