Recording low contrasts with a photothermoplastic information medium

The possibility of using a photothermoplastic information medium to record low contrasts km of an optical image is studied. It is shown that, for a sp atial frequency of 100 mm(-1), when the resolvometric latitude is L(R)great er than or equal to 0.7, using projection recording with visual evaluation, the SNR equals 50 and k(th)=0.015; using interference recording with instr umental evaluation (SNR =3), k(th)=0.002, and k(th)=0.0002 when SNR=0.2 and L(R)approximate to 0.1. (C) 1999 The Optical Society of America. [S1070-97 62(99)00701-0].