Accumulation Buffer

I use the accumulation buffer to provide antialiasing. When the background is black (glClearColor(0,0,0,0) and glClearAccum(0,0,0,0)), it’s ok but when it’s white the antialiased image is black with some colors : it isn’t what i’m expected.
I’m working on Octane Silicon Graphics with IRIX 6.5 and a four years old version of OpenGL.

Can you help me. Thank you

Could you show us some of your accum buffer functions and how your rendering the scene? Just some code may help.