The BEP experimented with different paper types with the 1928A and 1928B $1.00 issues and tried again with the 1935 $1.00 issue. The A-B block was printed using distinctive paper with a special finish. The B-B block was printed using special paper. The C-B block was printed using regular paper as a control. This is a C-B block bill: How are the 1935 experimental bills identified? The A-B block has serial numbers ranging from A00 000 001B through A06 180 000B. The B-B block has serial numbers ranging from B00 000 001B through B03 300 000B. The C-B block has serial numbers ranging from C00 000 001B through C03 300 000B. I have an A-B block and now a C-B block. A dealer told me he has only ever seen one B-B block bill. Looks like the B-B block will be a gap in my collection.
