For some reason neither Python Image Library nor OpenCV are able to open tif images
written by Blender 2.61. I havnt tried it under other versions though.
The files open fine in Matlab, MSPaint, Gimp, Photoshop.
I have found the file tiff.c in Blender 2.62 source which defines the use of Deflate compression and I changed it
TIFFSetField(image, TIFFTAG_COMPRESSION, COMPRESSION_DEFLATE);
TIFFSetField(image, TIFFTAG_COMPRESSION, COMPRESSION_PACKBITS);
and then recompiled.
This now works for both OpenCV and PIL.