Astonishingly, this actually has space history in it.

http://news.bbc.co.uk/1/hi/sci/tech/3387895.stm

"Computer researcher Don Mitchell used original digital data from two
Soviet Venera probes that landed in 1975. His reprocessed and
recalibrated images provide a much clearer view of the Venusian
surface..."

His page is at http://www.mentallandscape.com/V_Venus.htm ; the images
themselves seem to be ferreted away somewhere on a page that's 404ing,
but there's a good solid history of the Soviet (and the contemporary
American) program of Venus probes there. I've read parts of it, and
commend it to your attention...

--
-Andrew Gray