hard

Definition: (1) ~lighting: one giving rise to high-contrast lighting i.e. difference between shadows and lit areas in excess of about 1:20 e.g. from a spot-light or full sun. (2) ~ paper: one tending to print high-contrast images due limited range of exposure i.e. with a high-gamma light-sensitive layer. (3) ~ negative: one showing a high-contrast image, possibly as result of over-development. (4) ~ water: one with relatively high content of calcium or magnesium salts dissolved. (5) ~ x-rays: those of short wavelength, therefore high energy -- these penetrate deeply. (6) ~ coating: protective layer used on lenses, filters, etc., usually comparable in hardness to glass and applied on top of softer material e.g. plastics or another surface e.g. anti-reflection coating.

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