View Full Version : The alpha channel.

03-22-2003, 10:22 PM
Can someone tell me how to do alpha in photoshop or other programs?

Leslie Judge
03-23-2003, 06:33 AM
I tried Paint Shop Pro 7. In that I can make a mask from the actual picture or from an other one (so I can draw the mask separately if I want), then tweak it if necessary. The last step is that I save the mask to the alpha channel, then delete the mask with no merging into the picture.

When I save it as TGA, it displays a warning about only one alpha channel can be saved but that's enough. :)

03-23-2003, 07:37 AM
Aye. In PSP you can also quite easily just make a selection of the areas you want to be included and then save the selection into an alpha channel. Selections are easy to make for example with the Magic wand.

03-23-2003, 11:46 PM
I still dont get it.

03-23-2003, 11:47 PM
How do you save the selection in the alpha channel?

03-24-2003, 01:40 AM
In Paint Shop Pro, just do your selections, then go to the Selections menu and choose save to alpha channel. However, there's one catch in this business: if you are making, let's say a grate, what part of the picture do you save to the alpha channel? The grate itself or the black area, where you should see through the grate?

I have done different grates, glass with some non-transparent markings, and some other shaders with transparent areas, but still I don't automatically remember this... Eh, so I don't remember, before I have a look at some .tga I did before (or some Raven one). Luckily, you only have two choises. And no doubt somebody will post here the correct answer.

And remember it has to be a targa file. JPEGs never have but one layer, no alpha channels.

Leslie Judge
03-24-2003, 10:32 AM
:) It doesn't matter what part do you select, the grate or the gaps. You can use either, just need to modify the shader code properly. :)