Actinic Actinograph - Actinometer
35 fluid ounces) of the ordinary fixing bath, as made by dissolving one part of hypo in 4 parts of water, is mixed with 50 cubic centimetres (or about
![]() ![]() ![]() Actinic
![]() applies to that portion of light which effects chemical change, in distinction to those portions which furnish light and heat. The actinic portion of the spectrum may be said to be confined to the ultra-violet, violet, indigo, blue, and green; not, as might be supposed, to that portion which appears to us to be the most powerful - viz., the yellow. But*the division is entirely arbitrary, as all depends upon the substance exposed.
Actinic Focus of Lens. See Focal Length ; Chromatic Aberration; and Monocle.
Actinograph - Actinometer (as above, with
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![]() sures the actinism of the sun's rays. It usually consists of sensitive paper, which can be exposed to the light in small portions at a time; and the time which it takes to darken to a standard tint will be found to bear a distinct relation to the necessary exposure required for a sensitive film, whether upon glass or paper, due allowance being made for the presence of any object of importance near the foreground of picture. An actinometer can be made by any amateur by soaking a strip of gelatino-bromide paper in a 2 per cent, solution of nitrite of potash, drying the same in the dark. When dry it should be rolled up small and placed in the inside of a box which is light-
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