How to get stained glass leading into the alpha channel

In Photoshop, I can convert a colored design into a stained glass texture using the built-in stained glass texture filter. Is there any way to get the leading (the foreground-colored bands that separate the colored panes) into the alpha channel. I want to make the color panes slightly transparent.

I know that I can use the magic tool, but this is slow and unreliable. It seems like there should be an easier way.

the leading is usually all one color value isn't it? I'd try selecting it using color range on the select menu, and then invert if you have to.

Unfortunately, the leading is not all one color. Anti-alias causes a small range of colors. And the color of some elements of the leading may coincide with the color of adjacent parts of the glass. So to select the leading with the magic tool, you have to specify a color range, select, and then edit by hand to exclude or include pieces, at the pixel level. The selected object is very complex, so this is a tedious job. I was hoping photoshop, which knows what pixels belong to the leading and what do not, could be talked into highlighting exactly those pixels on the alpha channel.

I think you're giving Photoshop more credit than it deserves, AI wise. It does not know what pixels do and do not belong to the leading or to anything else after the filter has been applied. If it were done with vectors like it would be in Illustrator, then the program would retain "knowledge" of what is what. However, a Photoshop filter is just a way of mathmatically changing the lighting properties of all the pixels in a selected area, and once that change has been made no information about how it was done is retained by the program. A raster is a raster is a raster. It's just a collection of dots. Photoshop doesn't know or care which dot is which.

Edited to remove an error.
For a good solution to this problem, see Robin Sojourner's post below.

Thank you for your comments.

I had already tried the approach you describe in your last paragraph, and I tried it again after you suggested it again, but it doesn't work. The border on the alpha channel is different from the border on the picture. I tried it with just a blank picture. The attached jpg shows what I see on my screen after putting the stained glass texture on both the picture and the alpha.

The magic wand in pshop is generally terrible for making hard edged selections for the reasons you've already bumped into - it gets only partial pixels at the edges of the leading.

Here's another approach which may get you to where you want to be. Duplicate your active layer and max out the contrast with Auto-contrast. Then, apply Threshhold to this work layer to make the leading black and everything else white. Do a "select color" on the work layer and pick "shadow" to get only the leading. Create an alpha channel from the selection in the channel pallete, and then discard the work layer.

You may have to invert the alpha channel (make the channel active in the channel pallete and press Ctrl-I) because I *always* forget whether black or white is transparent in an alpha channel.

In case you don't already know this, when it comes time for your upload, make sure there is one and only one alpha channel in the channel list (flatten the image if you have to to get rid of other layer masks) and save the image as a TGA file at 32 bits and no compression. If you are using phsop v7.0 you *must* get the free v7.0.1 patch from adobe.com as the handling of TARGA alphas was badly broken in 7.0; the 7.0.1 patch fixes only that problem and nothing else. Good luck.

I second that, Malachi.
As several alphas can get quite messy sometimes.

Personally, I don't much care for the Stained Glass filter. I'd rather make "real" stained glass.

But, if you want to do it, here's how, in a few easy steps.



That's all there is to it!

Oh! And you don't need to eliminate your layer masks. They aren't really alpha channels, although they will show up in the palette if the layer is selected. But they disappear if you chose another layer. Only real Alpha Channels, which persist no matter what layer you have selected, need to be thinned down to one. (There can be only one! )

Hope this helps!

Whoops. That's what I get for posting at 4:30 in the morning I guess. Sorry about that. I will edit my post to remove the mistake so it doesn't confuse anybody. I'm gonna go stick my head under a rock now. Do what Robin said.

i skipped thru most replies so forgive me if this is incorrect or already answered.

save the texture as alpha as you would normaly.

then still in the alpha channel goto Image, adjustments and finally 'Levels'

This brings up the alpha channel levels so you can reduce or increase transparency

what you want is you make the lines or lead 'white' rather than 'black'


you do this by sliding the bottom sliders opposite ways there-for you making it like a negative this immediatly makes the lead/lines white and the glass parts transparent

these bottom sliders can further be used to adjut exactly how much transparency you want...move them to reach the level of grey or transparency you require in the glass but keep the lead/lines solid white for the opaque effect

this way you dont need to 'select' anything.

I hope this helps? & i am not repeating stuff already said

i use alphas a lot for my store textures and windows in walls etc...this trick was a revolation to me taught by some-one else in the forums...


let me know!

well last time I give MY knowledge away!

(

Sorry no one said thank you, LillyBeth. Teaching here can be a thankless job sometimes, but it's still worth doing. Most people who read the forums never post. Consider that so far 194 people have viewed this thread, but only 7 have posted in it. I'm sure your answer has helped a lot of people who for whatever reason choose not to respond.

I'll admit I'm a sucker for the thanks when it comes, and it really feels great when it does, but usually it doesn't. For what it's worth, my thanks go out to all who take the time to write here. Whether someone is volunteering to answer questions or whether it's simply having the guts to ask them, everyone on this forum is helping in the quest to make SL look as good as it can.

My motivation here, by the way, exists on several levels. First, I just can't stand to see people struggle to do something that I know how to do, so I feel compelled to chime in and say "Here's how". Second, and perhaps more selfishly, as a resident of SL I have to look at what people make every day. When the things around me are high quality, my experience is that much more enjoyable. When it's low quality, my experience is diminshed. Also, I believe the better SL looks, the more people will flock to it, which means more money in LL's pocket (and mine), which means more resources to make SL better and better. So, as far as I'm concerned, while it's great high when people take the time to say thank you, and I love that feeling, ultimately a better looking world is all the thanks we really need.

Please, keep up the good work, and I don't think anyone will mind if I presume to speak for everyone here when I say thank you for taking the time to help. We're all in this together.

oh im teasing...no, no im not LOL i admit it i was hoping for a 'wow !' lol

You know on the subject, one person here in the forums turned my life around Literally.

I was struggling with the old 'alpha's lol and one person whom i should go do my homework and name her here (but i wont lol cuz imlazy but i DID say ty) offered her advice and a mini tutorial and that one post has turned me into a big texture creator/modifier/seller and now provides me with a p/t income here in SL.

Without that shared knowledge I would be just another 'finder & uploader' offering stuff anyone can find but learning that one thing opened up so many other avenues in photoshop that ive gone on to learn so much more now on my own.

It was one hurdle that i couldnt get over ..bottom line ive learnt since then that paintprogams especialy Photoshop allows you probably 10 diferent ways to do the same thing! which is both a good and bad thing

I applaud anyone who shares here....especialy the business ppl as many keep their skills & secrets close to their chest for obvious reasons.

I'll give you that wow, LilyBeth!

And thank you for bumping this back up. lol