Posted by Alan Hakim on June 03, 2006 at 19:52:21 from 212.137.231.118 user awhakim.
In Reply to: Re: Night Sailing Picture in SA posted by Jock on June 03, 2006 at 09:49:42:
In those days, plates were made by photographing the original, transferring it to metal and then etching away the white parts.
The resulting 3-dimensional plate would get fuzzier with wear and tear on each print run.
You can see the same results in the letterpress used for the hardbacks; one reason why they were reset periodically.