Jump to: Board index » General » Fusion

Problem with transparent png

Learn about 3D compositing, animation, broadcast design and VFX workflows.
  • Author
  • Message
Offline

Darren Cook

  • Posts: 23
  • Joined: Fri Sep 29, 2017 3:31 pm

Problem with transparent png

PostWed Jan 24, 2018 12:01 pm

Has anyone had problems importing PNGs into Fusion 9, that were exported from GIMP?
I had the original PNG import fine. Then I loaded it into GIMP, chose colour-to-alpha (#000000), and saved it as a PNG. Bringing that one into Fusion 9 the colours are an awful mess. (But that same PNG displays fine everywhere else - it is just Fusion that cannot display it properly.)

Strangely the alpha layer is correct; it is the green and blue layers that seem to have gone wrong (which in itself is curious, as it is a mostly red/orange image). I was even able to use the alpha layer from my GIMP-exported image as a mask on the original PNG to get the desired effect?!

Anyway, I instead exported from GIMP as a tiff file, and that imports into Fusion 9 with no problems. So that is the workaround if anyone else hits the same bug.
Offline

Sander de Regt

  • Posts: 975
  • Joined: Thu Nov 13, 2014 10:09 pm

Re: Problem with transparent png

PostWed Jan 24, 2018 12:14 pm

Have you tried toggling the post/premultiplied options in the loader of the PNG? Usually this is part of the problem *and* solution with PNGs.
Sander de Regt

ShadowMaker SdR
The Netherlands
Offline

Darren Cook

  • Posts: 23
  • Joined: Fri Sep 29, 2017 3:31 pm

Re: Problem with transparent png

PostWed Jan 24, 2018 2:14 pm

Brilliant, thanks!
When I check the "Post-Multiply by Alpha" checkbox in the "Import" tab of the loader, it loads as I originally expected it to, and behaves exactly like the TIFF file without that checkbox.

Even more curiously, if I check it on the TIFF file I get a different look (the more transparent areas look to have become even more transparent) - which is almost exactly what I just about to spend 15 minutes in gimp trying to get. (I also cannot find an apply mode in the merge node that gives that effect - "difference", when over a black background is closest, but not identical.)
Offline

Chad Capeland

  • Posts: 1756
  • Joined: Mon Nov 10, 2014 9:40 pm

Re: Problem with transparent png

PostWed Jan 24, 2018 5:01 pm

PNGs are defined as being straight color. TIFFs are defined as being premultiplied. Whoever decided on these standards knew they had to pick one, and so they did. Personally, I think straight color makes the most sense, especially for 8 bit images, but there's nothing any of us can do about it now, the standards are what they are.
Chad Capeland
Indicated, LLC
www.floweffects.com

Return to Fusion

Who is online

Users browsing this forum: No registered users and 5 guests