How do you make a rasterized poster?

[CREATIVE!11]

Anyone know how to do something like this? Got a good printer and extra ink so I thought maybe I could print some A4 blocks and make a big poster for just my amusement.

Anyone got any advice how to do this? or a link to tutorial or anything? Someone did post here a while ago how to do it but I can't find the thread.

Thanks

 

[CREATIVE!11]

great thanks!

Do you need a minimum image size so the poster looks sharp? because one I Want to rasterbate isn't exactly huge its 360 x 572