Very strange PNG Alpha Channel behaviour . .

Grazie wrote on 2/23/2009, 9:18 PM

1] Copy to ClipBoard a graphic which has a transparent background and paste it into my Graphics Editor (PsP)

2] Once in PsP no alpha channel. It is presenting a Black solid background. OK, no problemo I'll create one.

3] Using same graphic in PsP create a graphic with an Alpha Channel and I can see this happen within the process happening, but the Alpha transparency does NOT reveal itself in PsP!!

. .and here's the kicker!

4] It DOES back in Vegas!!!

However, if I were to originally Save Image to Disc, from Vegas, this DOES carry over the Alpha channel directly int PsP!

The Skinny: Copy paste to PsP does NOT preserve Alpha and that graphic in PsP will not retain Alpha even if I force it in PsP! BUT Save Image to Disc from Vegas DOES preserve the Alpha when imported into PsP.

OK, this is with Paint Shop Pro, if you have it please check this for me and if you have Photoshop, please try the same:

A] Using an Alpha Channel (background transparent) graphic on Vegas Timeline Copy and Paste into Graphics package.

B] Using an Alpha Channel (background transparent) graphic on Vegas Timeline Save to Disc and Open in Graphics package.

I'm sure I have been here before . . .

TIA

Grazie

Comments

TheHappyFriar wrote on 2/23/2009, 9:49 PM

looks to me alpha channels aren't put in clipboard. i tried it with gimp & got the same results.

Grazie wrote on 2/23/2009, 9:58 PM

Thanks for trying Happy.

Can you now CREATE a PNG with an Alpha FROM that Paste?

Grazie

farss wrote on 2/24/2009, 12:03 AM

1) In Vegas white text on transparent BG. Copy to clipboard.

2) Open PS, File New. PS creates transparent layer of 720x576.

3) Paste. White text on black background is the result.

4) Use magic wand to select black and delete. Save as PNG.

5) Open In Vegas. Result is white text on transparent background.

I suspect the issue starts with Vegas copying from the preview monitor or somewhere close to that and it does not support an alpha channel.

Bob.

TheHappyFriar wrote on 2/24/2009, 6:40 AM

it's not vegas. I did a copy from a browser window, vegas & another program (i think infanview) to gimp & all the same results.

But your method doesn't really work: alpha can be less then on or off. I tested with an image that had an alpha under a graphic (50% transparent) & empty space. That changes the color of the graphic when there's no alpha.