defringing pink/red when adding alphas

I am subscribed to a texture website that allows me to dowload texures

many of them are meant to be on a transparent background...like those with a blue or pink backing..

ive seen this method used before

what i dont understand is

when i make/add an alpha channel i find black is the best background...or white if i reverse the slider in the 'levels' option when I am adding the alpha

but as much as i try to select the image from the pink or blue background it leaves a circle round my image

i have tried filling in the pink/blue bits with black via paintbucket but it is blotchy

what other ways are there of adding alphas?

i usualy either select the whole image and copy & paste into the alpha chennel or i will select image via the magic wand..inverse it copy it then paste that into the alpha channel

i have tried the above methods then cutting the pink/blue background away but it still leaves a fringe around the remaining texture I wish to add to an alpha

GGRR

any ideas?

I guess I'd have to see the effect you are describing to give you help. You seem to know the basics at the very least, so I don't want to insult you with easy answers.

Can you post the pic in question, or a link to it (so you can preserve the alphas)?

If you do a lot of image compositing, Extensis Mask Pro is a valuable tool for this. You'll have to determine if the roughly $200 price tag is worth it for your applications. It plugs into Photoshop, but also works stand alone. Most of what Mask Pro does is speed up what would normally take longer to duplicate in Photoshop, or another image editor. In other words it's a effective time saver, and in most cases a lot more intuitive than methods used in Photoshop.

Thanks for this,

I went to the website...and WOW my plug in add ons are bleak after reading about this and the many other PS plug ins I can use & buy ...but when it gets so a plug in costs more than the 'engine' its being plugged into I kinda have to stop

yes i would use this plug in a lot...i found another called Fluid Mask...looked very good but that was $499 ( ouch)

i suppose what ive learnt from this is ....to look for free plug ins 1st...see what kinda effects I can create with plug ins..i had assumed PS was a stand alone product really but having said that I use a plug in for making textures seamless..so it stands to reason there would be other good plug ins.

No Im not prepared to pay that quite yet..i dont make money from PS its purely pleasure...i dont use it for commercial purposes in SL or RL im not that good !

But I have learnt about the powers of plug ins and how important they can be

I am at the stage when PS is just kicking in regards to my understanding and I seem to be learning more & more short cuts each day I use it.

I havent even USED the mask options yet so I know I have only scratched the surface...what I know I learnt largely from tuts and from here in the forums.

Dizzy, did you try changing the amount of tolerance to get rid of the pink fringe you refer to? Also, rather than using a "paint bucket" you could try the selection tool where you get much more precise results.

A lot of gaming texture artists utilize this hot pink color to make creating opacity maps much simpler.

Also, you should always double-check the licenses for the textures you use if you don't create them yourself, if you intend to offer them in a texture store, either in SecondLife or elsewhere. Many places wouldn't like it if you re-sold their work and called it your own. . . . but as a business owner you probably already knew that.

Hi Dizzy! What you are seeing is probably the result of the anti-aliasing around the original image. (But then, you probably already knew that.)

There are a couple of ways to make it "go away," that don't include the use of another expensive plug-in.

Since you are working directly in the Alpha channel, simply blurring the Alpha might do it, as it would give you partial transparency in the problem areas. But, since that transparency will be placed on white when you import to SL, that's not going to work unless your image is very, very light in the first place.

If I were you, I'd extract the image first, and put it on a transparent background. That will allow you to use the special PS tools that are there to manage this kind of problem, and also allow you to match the colors on a layer beneath the image, which will eliminate the white halo in SL.

Extracting the image is fairly simple.

First, if it's on a locked Background layer, you need to get it on a normal layer. You can do that by just double clicking on the layer, and clicking OK in the dialog that opens. (Or if you want to skip the dialog, hold down Option/alt when you double click.)

Or you can make a copy of the background on the layer above by simply tapping Command/ctrl J, and work on that layer.

Once you've done that...

If your version of PS has the Extract Filter, you can use that. It's very good about making semi-transparent pixels on the edges of things. (Let me know if you need a short tut about how to use the thing.)

Or, you can make your selection as you normally would, and then use the Defringing tools to get the red out. You'll find them at the bottom of the Layer menu, under Matting.

Or, since your selection is on a solid color background, you can use the Magic Wand to select it, then go to Select > Expand and expand it by one pixel. Hold down Option/alt and click the background again, to subtract the background from the selection. That will leave a 1 pixel selection that surrounds your image. (There are a few other ways to do that, but I've found this method to be the fastest, for me anyway. Feel free to try a different one.)

Then, go to Edit > Fill, choose 50% opacity, and Clear as your Blending Mode. (If Clear is dimmed, you forgot to make the Background into a layer. Also, it doesn't matter what is in the Fill portion, since it's not really going to be used.) That will reduce the opacity of that single pixel outline to 50%, which might be enough to make the red unnoticable, especially if you place another layer under it, for those semi-transparent pixels to "pick up" when brought into SL.

However you do it, when you are ready to make the Alpha, just hold down Command/ctrl, click on the thumbnail image of that layer in the layer palette, and Save Selection. If there's already an Alpha, Replace it; otherwise make a New one. (Remember, there can be only one.)

Hope this helps!

Thanks Guys ...altho its a VERY old post Ive 'moved on' since then

But Robin as ever your detailed reply was superb and I am sure I will learn from it next time I am faced with this situation.

What I have learnt is to use the magic wand in the color area, obviously set the tolerence accordingly. then 'select similar' and holding ctrl down keep hitting the area till I have it all then 'cut' and then ' fill' with a color very similar to the piece I want to remain opaque.

its like most things in life trial and error but as this is my alt account my main acct being a texture creator and seller in SL I have learnt a lot in the way of techniques since this very old post