you should never use default shaders if you’re using syphon.
use Syphon/diffuse instead and tell me if it works.
default shaders typically have a flag that masks the alpha channel out, which, depending on a number of factors, may affect the final blend output. Syphon materials have this mask, //Colormask RGBA, commented out in the shaders.
normally this only affects you in a major way if you’re trying to use the background as a transparent alpha channel. However, this could be a more generalized issue than previously thought. let me know about your results after trying the Syphon shader instead, and we’ll see if that’s the case.
Also, come to think of it, I do recall needing glDisable(GL_LIGHTING); in my plugin. I don’t know if that ever made it to the released version. Will check right now- EDIT: glDisable(GL_LIGHTING) is indeed in the plugin, so that’s not your issue.