Answer:

ENL

AnswerCrossword Clue
ENLFilm-developer's abbr.
ENLPhotog's abbr.
ENLLike a sgt.
ENLPhoto lab order (abbr.)
ENLLike a pfc.
ENLMake bigger (abbr.)
ENLSigned up (abbr.)
ENLCopier blow-up (abbr.)
ENLBig picture? (abbr.)
ENLBlow up (abbr.)
ENLBlown up (abbr.)
ENLBigger pic (abbr.)
ENLBlow-up (abbr.)
ENLBlowup: Abbr.
ENLBigger pic
ENLPhoto blowup
ENLPhoto lab svc.
ENL8x10, say: Abbr.
ENLLike mil. volunteers
ENLBigger picture: Abbr.
ENLLab svc.
ENLPhoto lab ord.
ENLBig picture: Abbr.
ENLPhoto lab prod.
ENLPhotog.'s blowup
ENLBlown-up: Abbr.
ENL8 x 10, e.g.: Abbr.
ENLBig picture?: Abbr.
ENLIt usually shows more detail: Abbr.
ENLLike a USN volunteer
ENLBigger photo: Abbr.
ENLLike USN volunteers
ENLPhotographer's order: Abbr.
ENLCommercial development done in one hr.?
ENLIt's bigger than the neg.
ENLLab blowup: Abbr.
ENLBlowup (abbr.)
ENLDarkroom abbr.
ENLFotomat abbr.
ENLPhotog. lab product