Eugen: You must be a young guy...
That is very interesting. I never seen rolls of 20. Never thought somebody produced them. Know only about 12, 24 and 36 rolls.
...back in the day there were no 12's and no 24's.....just 20 and 36.
The 12's, 24's and later the 27's started to appear in the late 80's.
Slide film was the last to change.
I think Ilford made a 72 exposure full frame roll of film back then. Someone correct me, but it might have been HP-5.
Agfa made some 15 exposure color rolls around 1992 as "freebies" with multi-roll purchases.
Anyway, all the film in the ad is sold.
Thanks.