This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Gilt Edge 27.
690. This is the fastest plate we make. It is especially suited for all extremely short exposures and flash-light work. Speed is a great help in winter, for then the light almost always seems stronger than it really is, and under-exposures are frequent. On such days when the light is changeable and uncertain, Gilt Edge plates make the most of short exposure and their unusual latitude saves many plates, even when there is large error on the side of over-timing. Owing to their extreme rapidity in portrait work the lighting of the subject should show more snap and roundness than when a slower plate is used. Quality has not been sacrificed to speed in our twenty-seven. It has the fine grain and characteristic Seeds gradation, which means pictures with harmonious contrasts, softness and depth.
691. Our 26x is the most extensively used plate we make. For general portrait work it cannot be surpassed. It gives roundness in gradation from the highest lights to the deepest shadows. There is brilliancy, harmony, and detail through the whole picture. Light the subject as you would have your picture. Only extremes, i. e., light so strong and concentrated as to show unusual harshness, or so broad and so much diffused as to give no point to highlight or shadow, need be avoided. The plate will give you what you see under most adverse circumstances. The 26x plate has a wider latitude than any other portrait plate in the world. It requires one-fourth more exposure than the Gilt Edge 27.
Seeds Tropical Plates. The Seeds Tropical is a new plate made for use in hot climates, which will be heartily-welcomed wherever heat and humidity make the working of the ordinary plate a difficult matter.
The Seeds Tropical Plate is similar in speed, latitude and gradation to the Seeds 26X, but will not frill, even though the temperature of the developer be as high as ninety degrees Fahr. The proper temperature for working this plate is in fact from seventy degrees to ninety degrees without danger of frilling, and thus gives the benefit of the "Seeds quality" to those who, on account of climate or on account of difficulty in obtaining ice, are not able to properly control the temperature of their solutions.
Note. - Developer made up according to the regular formula is intended for use at a temperature of about seventy degrees. If development is carried on at eighty- five degrees or ninety degrees the developer must be diluted one-half by adding water, using fourteen ounces instead of seven ounces.