Merge Alpha Channels?

HIyas Everyone,

I finally started some tutorials this weekend and I'm stuck on an alpha problem.

I want to create a small sign with some text using a nice font and have the background as alpha. Creating a single channel alpha is no problem but, in the lettering, I have small spaces that need to be alpha too. I can create more alpha channels but I know I'm limited to just one for a .tar file. How is this resolved? All help will be greatly appreciated!

Stating the graphics application your working in may be helpful. I am not familiar with .tar
files as I have not needed to use them.

Assuming you are using Photoshop for a simple sign you can actually bypass the alpha channel tab altogether. Create a new file and you will be presented with a box that offers you
various choices for size and resolution etc, make sure that under "background contents'
you choose "transparent". Then your background will be white and grey squares which indicates that this area will be transparent. Choose your text tool and do what you need to do.
Then if you need to make changes you can either step backward under the edit dropdown menu or you can also add things by simply creating a "new layer" which in my program PS CS2 is automatically transparent. You can have as many layers as your memory will allow.
Then when it is time to save your file under "layers" choose "merge visible" then save it as
a .PNG file.

SL recently allowed the use of PNG files (portable network graphics) which make handling tranparencies really easy.

If you are doing the tutorials to learn all the exact methods then just file this advice as a
quick easy option.

I use alpha channels for certain very specific techniques but for something like a simple
sign this way works just as well.

Thanx Infiniview... yes I'm using Photoshop CS2. Okies... I was using targa for the alpha channel but if png will do the trick, I will give that a try

Zena, it sounds to me like you have the basic idea right, but are confused about the details.

Briefly put...

When you work on an image in PS, GIMP, or other, it is organized into one or more layers...in your case, the signboard is on one or more layers, and the lettering is on other higher layers (I think, from what you say). Some of those layers have transparent parts that let lower layers shine through. People sometimes use higher layers that are partially transparent to let lower images sort of weakly bleed through. Lots of other uses, and the experts do even more...

When you get your image in PSP to look right, then you export it or save it as a targa (.tga, not .tar), a .png, a .jpeg, or whatever. These are the three most common SL choices.

In any case, this save will flatten out or merge all your visible layers a one layer file. In many cases, the final image no longer needs any transparency because each final pixel is solid.

If the image also contains some transparency, use targa or png, because those formats can save the transparency from the alpha channel. If there is NOT transparency in your final image, then you do not need to save the alpha channel. jpg cannot.

I like PNG, but a lot of older super-guru-pros prefer targa.

PNG is fine, but don't give up on alpha as "difficult." It's not. You might need transparency because, say, you are creating a five-sided sign texture that you are going to put on a flattened cube prim in SL. All you need to do is draw your pentagonal shape on a fresh layer, select all pixels, open the Channels palette, and click the little mask icon (the one that looks like a rectangle with a circle in it). Bingo! Instant Alpha. Save as .TGA. Anything outside the pentagonal shape will be transparent on your prim.

If you need transparency inside the shape -- maybe to look like a bullet hole through your sign? -- then clear the pixels for the hole on your sign shape before you create the alpha.

I thought I had to create an alpha layer for each area of pixels I was using the Magic Wand on until I found Magic Eraser.. wooo hooo!