[charlesedward]

The print is black ink against an off-white backgroup appearing like " a mass of people". The shape is likened to a backword letter "S" and the people seem to following one another in a northern direction. The artist signature may be O'Kallen 67 and is number 12/3z.

[genericreader]

Without seeing the exact print, it's hard to tell, but if your estimation of "O'Kallen 67" is correct, you have the artist's name, and probably the year in which the print was made (1967). The other number "12/3z" is puzzling; usually what you find on a print is its edition, like "AP" ("Artist's Proof" -- the best version made before printing in large quantities); or "5/200" (fifth imprint of a lot of 200). "12/3z" doesn't really give anything to go on. Could "3z" be an actual number instead?

If you can scan that portion and that of the print in general, it would be very helpful.