Digital BW, The Print

There must be some interesting explanation about how and why England 
and Europe use A4 etc. paper and US uses Letter sized (and other 
sizes).

How and why did they get different standards.

I see that A4 fits a 35mm aspect ratio full frame. Letter size 
doesn't fit either full frame or 8x10 (probably another explanation 
about 8x10).

Just interested in this...I think about it every month when I see the 
two paper sizes. It's funny how we've reduced the size of the world 
digitally but not on paper <g>.

thanks and cheers,

Tom O'Connell