Abstract
The influence of sharpness degradation S (caused by diffusion sheets) and gradation G on the quality of 10 x 16 cm B/W transparencies of four different scenes has been studied. Quality, sharpness and gradation have been judged by 50 observers to yield the scale values Ψq, Ψs and Ψg. The main results are: (1) the judgements of quality Ψq, sharpness Ψs and gradation Ψg form a linear combination which depends on the scene: Ψq=a0+asΨs+agΨg. Simple relationships exist: (2) between the photographic y value and the gradation judgements Ψg: Ψg=klogγ+B (3) between the sharpness degradation factor S and the modulation transfer function MTF = M(v): S = 1_log M(v)/C.v (4) and between the MTF and the sharpness judgements Ψs, dependent on scene and gradation, of the form: Ψs = ks·S+Bs

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