Digital BW, The Print

Julian,
Originally I didn't know that I couldn't use either side. 
I lucked out the first couple of times I used it and got 
good scans. Then, when I did get rings on a scan, I 
figured out  that only one side is coated (I _think_ it's 
a coating). I tried both sides and found the side that 
doesn't  create Newton rings and marked it. It was a 
trial and error process. 
Maybe the supplier  or someone else on the list 
could provide a better method.
Peter
> so how do i tell?
> 
> julian