Orthochromatic Photography: simply explained and illustrated

The object of this little book let is to explain to the amateur photographer wherein lies the difference between an Orthocbrome plate and a Non-Orthochrorne plate, and to illustrate by a few pictures how coloured objects a re rendered by the two classes of plates. There is no doubt that for some subjects Orthochrome plates offer decided advantages: they are particiilarly useful in landscape photography in Spring and Autumn when the foliage assumes such infinite variety of tints, also for Architectural work where coloured stone or marble, stained-glass windows, and so forth have to be photograp hed, and a t all times when it is desired to secure clouds, which on a Non-Orthoplate usually print out blank. For copying coloured articles and pictures they are indispensable. As with other Orthochrome plates, it is necessary to have a Light-Filter when Imperial Special Sensitive Ortho. (S.S.O.) and Special Rapid Ortho. (S.R.O.) plates are used, to secure the full benefits of their Orthochromatism, but the Non-Filter (N.F.) plate is unique as regards its Orthochromatic properties. Its sensitiveness to yellow and green has been raised to such a point that it may be used without a Filter for all average subjects, and a filter is only necessary when subjects including great colour contrasts have to be photographed.

It must not be forgotten that the use of Orthochrome plates is not confined to the photography of such subjects as mentioned in the last paragraph; they are suitable for all subjects, and when used without a light-filter will do all that a non-orthochrorme plate will do. vVe need hardly enlarge on the position Imperial plates hold in the photographic world. By their high quality and reliability under every condition they have taken the premier position, and a well known and appreciated not only in Great Br tain , but in every country in the world . A position of this kind is not won by chance or haphazard methods, but by close attention to every detail of manufacture, by using only the very highest class of materials , and by rigorous tests of the finished product before it is sent out for use. Every batch of plates is carefully examined and tested fo r speed, the correct speed-number being stamped on each box of plates. We confidently ask our friends to test our plates in comparison with any others, when they will not be found wanting , either in speed or quality.