New Alpha Channel Tut and PS Actions

Hi Everyone!

As all of you who have been here for very long know, there are lots of questions about Alpha Channels, White Halos, and so on.

A long time ago, I responded to one of the posts by making a set of Photoshop Actions that would, essentially, do all the work for you (if you use Photoshop.) Just load the Actions, click one button, and sit back.

However, I never got around to making a front end for them, or writing the tutorial explaining how to make Alpha Channels manually. Until this week.

It's up now, on my site, along with a link to the free Flaming Pear plugins that make it possible to eliminate the halo on even the most colorful of images, and a link to the Actions.

Hope this helps all those who were confused, and that it also helps speed the process for people who aren't, but who don't mind saving time through automation.

Click here to go to the page where you can start the tutorial.

Enjoy!

Thank you very much Robin.



Very good information.

You are very welcome, Bree!

To combine two posts;

Someone just wrote me a PM, telling me that he can't figure out Alpha channels, and that he was following Amber's Tattoo Tutorial, but he had to drop the "selection dots" (which are actually called Marching Ants. Yep, that's the honest Technical Term used by Adobe,) to make the underlying layer Black. He thought that also made the layer with the tattoo black, so he deleted the underlying layer.

And then couldn't make the tattoo work (there was no transparency) even when he used my Actions to make the Alpha channel.

I'm posting my answer here, because it was too long to post as a PM, and also because I strongly feel that questions should be asked (and answered) here in the forum. That allows more than one person to answer, and also allows more than one to be helped by reading the answer.

However, as it usually does, this all comes down to a single statement, made famous by the Highlander movies and tv show.



If you have more than a single Alpha channel, all Adobe products will create a totally white (opaque) channel when they save the image in the Targa (.tga) format. So make sure that you have deleted all the extra Alphas.

In PS, select a layer with no mask, and look at the channels palette. You should see exactly 4 channels. One each for Red, Green, Blue, and Alpha.

(If you select a layer that has a mask, you'll also see the Layer Mask in the Channels palette, but that's a temporary channel, and will be clearly labeled as a mask, in italics.)

If you see more than 4, delete the extras.

In PSE, go to Select > Delete Selections. If there's more than one thing in the list, delete all but one. (If you name the one you want to keep Alpha when you make it, that makes it easy.)

Then, when you upload, make sure that you can see the checkerboard behind your image in the Preview windows, or the mustard-colored "skin" layer if you are previewing on a mesh (skirt or body part.)

If you can't, then you don't have transparency. Don't waste your L$10. Go back, and make sure that you have exactly one Alpha, with an image on it, and that you have saved as a 32 bit targa. (PSE users can Load the Selection. If the whole page isn't selected, there is something on the Alpha.)

If you have done both of these things, then you WILL have transparency. You might not have the transparency you want, but it will be there.

Marching ants, by the way, control where pixels can and cannot be filled in. You can never fill pixels outside a selection. That's what the selection is for.

Only one layer can ever be filled at a time. That's the one that's selected (highlighted in the Layers palette.) You can highlight more than one layer, with PS CS and PS CS2, but you will find that the menu commands to add pixels (Fill, etc.) are dimmed when you do, and the tools that add pixels (Paintbrush, Paintbucket, etc. give you a Universal NO symbol (circle with a slash through it,) when you place the cursor over your image.

So it is completely impossible for PS to have filled your tattoo layer when you filled the background layer. The whole thing probably looked black, but that was because you were looking at the two layers on top of each other. To see a layer in isolation, hold down the Option/alt key, and click the eye icon to the left of the layer.

Hole down Option/alt and click it again to see the all the layers you were looking at before.

That being said, it wouldn't matter at all if you had filled the layer with the tattoo, as long as you had exactly one Alpha channel with the image of your tattoo in it.

When you make the .tga file, the image is going to be flattened anyway. (Targa doesn't support layers.) The transparency is driven entirely by the Alpha channel, and not by anything at all in any of the layers in your original image. All layer transparency is lost when the image is flattened.

So, to recap; You need exactly one alpha channel, with something on it, and a 32 bit .tga file to make transparency in SL. If you have these things, you will have transparency. It's as easy as that.

Hope this helps!