Are Four 74HC595 Sift-registers in a row too many?

runaway_pancake:
This display ?
http://www.youtu.be/OW8FVmrA7js
has 9 '595s daisy-chained.
The display has 70 pixels, the 595s have 72 outputs total, so I have to knock out two dummy bits at the end to push everything through.

Hey, that looks super cool!

I don't really get the dummy bit part? Could you share some of your code for me in order to understand? I'm a bit stuck with the transfer part...how do I address one specific pin of one of the 4 registers and shut up all the others?

Cheers!