Hello guys… I´m currently creating an animation and I have a problem. There´s a plane with a simple text applied over it (a transparent PNG), but when I render it, the transparency gets some weird artifacts.
I attached a PNG file with a screenshot of both the problematic rendered image and also with the texture settings. Does anyone have a clue on what I´m doing wrong?
Thanks in advance!
Leandro.
Try selecting the ‘Premul’ button in the texture settings (F6) and/or in the render settings (F10).
Bingo!
Thanks, Richard. What exactly the Premul button does?
http://wiki.blender.org/index.php/Doc:Reference/Panels/Scene/Render/Render
Premul - or Pre-Multiply. The ‘Sky/background’ is never filled in. The alpha in the picture is delivered as “Pre-multiplication”; a white pixel with an alpha value 0.5 becomes: (RGBA bytes) 128, 128, 128, 128. The colour values are thus pre-multiplied by the alpha value in advance. Use “Premul” alpha for post-processing such as filtering or scaling. Remember to select the RGBA option before saving. When Blender reads RGBA files, “Premul” is considered the standard.
“When Blender reads RGBA files, “Premul” is considered the standard.”
So it´s weird it did not activate Premul. Anyway, problem solved. Thanks once again. 
