Proto Mid-Period
These three records pre-date what I'm calling the Mid-Period of Hip-Hop and are all from 1987-88. If you were trying to define this period it would be from 1990 until the Wu-Tang's "Protect Ya Neck". So for instance (and tellingly if you look at the LP's visual iconography) Eric B and Rakim's "Let The Rhythm Hit Em" (1990) is in, but all the Wu solo LPs (by merit of their pointedly inaccessible content are out). If there is one clear visual signifier it's in a thrillingly up-front, though somehow exclusive, idea of black-ness. The cover for Black Moon's "Enta Da Stage", with its "so-black-it's-saturated-red" sleeve is paradigmatic.
The pugilistic Black Pride evinced in Public Enemy's music was taken to the next level; Black Pride was a given, naturally! Where once record sleeves tried to dodge the race issue now they celebrated difference. Sonically this went hand in hand with a shift (pioneered initially by Marley Marl) by a shift from using neither electronic instrumentation nor rock hooks, but a delight in funk samples. Concomitant with that was a celebration of Black History.