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Poser - OFFICIAL F.A.Q (Last Updated: 2024 Nov 18 10:25 pm)



Subject: alpha channel with .png oddity


operaguy ( ) posted Mon, 25 June 2012 at 8:03 AM · edited Tue, 01 October 2024 at 9:39 PM

When I render out to .png with the proper settings, I "seem" to get the correct file...when i open it in a picture viewer or browser window, the background is transparent.

However, when I open the file in my 2D graphics program, the background is NOT transparent; there is a light gray backdrop opaque filler.

I believe I am following directions:

render over black; no objects in the background; no dome.

Anyway, here is the file:

http://jrdonohue.com/andy1.png

when you view it in browser, background is transparent (or white?). Could someone download that file and open it in photoshop or gimp or some other program and tell me if the background is transparent?

It could just be my particular program (Canvas), but I have heard others report this same wierdness.

Thanks,

::::: Opera :::::


LaurieA ( ) posted Mon, 25 June 2012 at 8:08 AM

Hi operaguy :). When I open ur file in Photoshop 7, I get transparent in the background.

Laurie



operaguy ( ) posted Mon, 25 June 2012 at 8:28 AM

thanks Laurie. must be something odd in my 2D program.


EnglishBob ( ) posted Mon, 25 June 2012 at 9:37 AM

For what it's worth, the background is transparent in Paint Shop Pro 7, and in The Gimp. Some image viewers/editors don't respect the alpha channel - IrfanView for instance. Could you achieve what you want by going via Gimp - maybe translating to another format which Canvas will read alpha channel from?


operaguy ( ) posted Mon, 25 June 2012 at 9:53 AM

Thanks EB, good to hear that the channel is respected in gimp and paint shop. This means it is Canvas which is the issue. I'm going to look for a setting or a forum post about it.

I have been using Canvas for more than 15 years! It is a fantastic paint AND vector program.

By the way, I downloaded Gimp and installed it.....no icon appeared on my desktop for a launcher, and searching high and low in the folders it installed I could not figure out how to launch the program!

:: og ::


EnglishBob ( ) posted Mon, 25 June 2012 at 1:12 PM

I can't help there, sorry - is there a Gimp expert in the house? :-)

I have the portable version of Gimp, and that only as a backup in case PSP isn't available. 


hborre ( ) posted Mon, 25 June 2012 at 1:21 PM

I have an icon on my desktop for GIMP.  Don't recall doing anything extra or unusual.


operaguy ( ) posted Mon, 25 June 2012 at 2:16 PM

can you tell me what file it runs when you click it, assuming it is a shortcut, right?

 


LaurieA ( ) posted Mon, 25 June 2012 at 2:26 PM

The executable for GIMP is in the bin folder if I remember correctly.



operaguy ( ) posted Mon, 25 June 2012 at 2:44 PM

found it in bin, don't know how i missed it earlier

 

gimp-2.8.exe


shvrdavid ( ) posted Mon, 25 June 2012 at 7:15 PM

Are you sure that the grey you see is actually in the image, or is it just how the 2D program displays the transparent area?

To test it, save the file from the program and see if it appears correctly in explorer, etc.

Many 2D paint programs will allow you to change how transparency is displayed in the document window.



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operaguy ( ) posted Mon, 25 June 2012 at 7:18 PM

the gray is NOT in the image. just opening it in a browser window or another 2d program you get the transparent background.

There is some issue with Canvas, or as you say some "trigger" that will release the channel into transparency. Ive posted on two canvas forums, awaiting response.

 

Thanks

::::: Opera :::::


lmckenzie ( ) posted Mon, 25 June 2012 at 10:05 PM

XnView shows a black or dark gray background but using the Extract Channel command to extract the alpha channel extracts it correctly. Apparently the black background is the norm for this, as it was the same with a .png that I created. Some applications use a gray & white checkerboard for transparency. Perhaps Canvas is recognizing the transparency. If it has some kind of channel manipulation commands, check to be sure.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken


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