New Tut! Find out what those Pesky Alpha Channels really are!

I've been trying to explain how to make Alpha Channels for some years now, and have finally reached the conclusion that the main problem people are having is that they have no real grasp of what a Channel is, in the first place.

If you don't know that, it's virtually impossible to understand what an Alpha channel is, and how to make one.

So I've just posted a new tutorial on my site to help everyone finally understand, on a near intuitive level, what Channels are, how they work, and exactly what you can expect when you start to use them.

Depending on how long you play with them once you get going, this tutorial could take as little as ten minutes or as long .. well.. as long as it takes.

But once you've done it, I don't think that Alpha Channels will ever confuse you again.

You'll find it at
http://www.robinwood.com/Catalog/Technical/SL-Tuts/SLPages/AChannelDiscover1.html

Let me know how I did!

*applauds*

Well done, and fun and entertaining to boot! Nice one Robin.

Great For Photoshop. But, in PSP the alpha channel is a mask and it is in the layers column. So, this is a photoshop only tut. But it is still nice!

It doesn't make any difference which program you use. An Alpha channel is an alpha channel is an alpha channel. The important thing about this tutorial is not the mechanics of how to make one -- those instructions vary from one program to the next -- but what an alpha channel IS. I love it. Thanks, Robin!

The only thing that's missing, for those that still don't see why you might want an alpha channel when you can get the same effect with PNG, is an explanation of how the two differ. There are times when you ought to use an alpha channel in order to retain some working flexibility, but that's not intuitively obvious.

Wow, easily the best explanation of alpha channels I have ever seen- I hope even my PS-illiterate fiance will now understand them.... *waves to Raynor*

I especially love the part "see what happens-nothing!"

Fabulous, Robin.

Good stuff, Robin. Hopefully more people will get it now. I'll add a link to this in the transparency guide thread.


By the way, Thunderclap, it's not that in PSP the alpha channel IS a mask. It's just that since PSP has no channels palette, a mask happens to be a convenient tool by which to create a similar set of information, which can then be copied to the channel afterwards. You can work the same way in Photoshop too if you want. PS just happens to have other, more direct, methods available as well, so most people don't do it that way.

Whichever program you're using, if the copy-mask-to-channel method is your work flow of choice, the proper thing to do after copying the mask to the channel is to delete the mask itself. The channel will remain intact even after the mask is gone since they are two separate things.

A channel can be copied from a mask, and vise versa, but that doesn't mean a channel and a mask are the same thing.

Thanks, everyone!

I had no idea that you couldn't see the Channels in PSP, any more than you can in PSE. That makes some of the questions that people have asked me about PSP make more sense. (Not that I can answer those questions. I'm on a Mac, and have never even seen PSP.)

But yeah; whether you can see them or not, this is how Channels work.

You just can't do the experiments, if you can't get to the Channels, so you won't be able to get that intuitive feeling for them.

It might almost be worth downloading the Demo of PS (which you can do for free) to play with the channels, and get that basic intuitive understanding.

Rolig, this tut is really the first chapter in another book that I'm working on for the Texture Library. It'll be a while before it's ready, because I'm trying to get product out, too. But when it's done, I plan to have all kinds of things you can do with Channels besides just make Alphas that drive transparency in SL. (That stuff really will be PS only, though, I'm afraid.)

One of the things that makes me crazy about working for SL is that I have to delete all the other Channels before I can upload. I'm used to having multiple channels in a document, as well as multiple layers, so that I can work very quickly and easily.

But then, I haven't used any raster program except Photoshop since it came out; so I have decades of habits and experience there.

Chosen, do you want me to put this in the Sticky about Alphas? I debated about where to post it, and finally decided to put it in its own thread, so it wouldn't get lost in the Sticky. (I have a feeling that a lot of people look at the length of that one, and just throw up their arms and skip to the end.)

Anyway, thanks again!

Robin, I've copied your link to the sticky. I put it at the end of the FAQ section, under the heading "Further Information".

I think you're probably right that a lot of the information in that thread gets lost since it's so long. I'm not sure there's any good solution for that.

Cool, Robin! Like most people, I have taught myself how to fly Photoshop by trial and error and by following tips that you and others have dropped along the way. Every once in a while, I discover some fascinating hole in my knowledge. Usually I learn a way to fill the hole by experimenting, but it's always fun to find that someone with more experience has had the foresight to create a tutorial that I can play with. You've been there for me more than once. I'll look forward to the book. Thanks!