My neutral density filters seem to add a purple-ish cast. It is hardly noticeable with the ND 2 and pretty heavy with the ND 8. I'm hoping to shoot some waterfalls on an upcoming trip (alas, waterfalls in the Texas Panhandle are nonexistent!) and had planned to use an ND filter to help get that flowing effect. BUT, I don't want purple!
I shoot RAW so I will have correction abilities but I'd rather get it right in the camera.