The more sensitive the plate emulsion, or as we are accustomed to say, the greater the speed of the plate, the greater must be the precautions taken to protect it from light fog.

How safe is your dark room light? Just how sensitive must a plate be before your light begins to fog it during development?

Seed Gilt Edge 30 Plates and Eastman Portrait Films have exceptional speed. In fact are so sensitive that we know of cases where a dark-room light that was safe enough for an ordinary plate produced fog during development of Seed 30 Plates and Portrait Films.

The only way to get the benefit of speed in a plate or film emulsion is to be sure the degrading influence of fog is eliminated. If the emulsion is sensitive enough to produce a good negative with very little exposure, it will also yield a badly fogged negative with very little exposure to extraneous light.

Test your dark-room light with the plate which has the most speed. Cover half of a plate and allow it to stand in the light by which you develop, for the length of time required to develop. Then develop the test you have made in absolute darkness. If half of the plate is clear and half fogged your light is not safe.

The effect of a slight fog on a fast plate is to destroy a certain amount of the gradation. This leaves the negative soft and flat, lacking in the snap and brilliancy which the plate is capable of producing with proper exposure and development.There is no question but what many photographers get this result without knowing the cause. Many times the plate is blamed but as often it is the paper that is condemned for not yielding snappy prints.

Look for the trouble first of all. Learn whether your negatives are as clear and brilliant as they should be. If they are not, examine your developing light, and make it safe.Much of the fog from a darkroom light is due to the examination of the plate too often and too close to the light. This is unnecessary, and since it is so detrimental to the quality of the negative the habit should be broken.

Reversal of the image, which gives you a positive, is also caused by examining the negative by unsafe light during development. You have developed part of the image and in holding the negative to the light that image is printed on the unexposed silver back of it. The result is a partial positive.

Examine and test your developing light.

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By Sara F. T. Price

{Of the Women's Federation)Mt. Airy, Philadelphia, Pa.

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