Thanks for the tips, Eric and TOXE. I forgot to mention that the same scene, rendered without Toon, works o.k. at 3200X2400 as TIFF, with "mask" checked in the g-buffer list. But I get the feeling that even if I turn off "mask", it will still use the same amount of memory during a Toon render. The scene is for a paying client, and I don't have permission to send it out. I will try going to 300 MB, which may not work, since I only have 256 MB physical RAM. I can stitch them in Photoshop, but how do I set up the quarter-renders of the full scene without introducing various parallax errors? In this case, there's a character right in the middle, so how would I avoid seams and splits?