A UNIVERSAL DEVELOPER.

By MAXIMILIAN TOCH, F.C.S.

IMPLICITY is one of the most desirable objects. in science as well as in art. Some years ago there was a fairly good plate on the market to which a formula for developing was attached that was enough to scare even a practical apothecary. There were nine different items in this developer, and as the manufacturers were not responsible for results unless their formula was particularly carried out, the plate eventually disappeared from the market and the firm went into bankruptcy. The first simple formula, was published by the old Nepera Chemical Company, when Velox was originally exploited.

This formula invented by Dr. Leo Baekeland, the inventor of Velox, is used to this day, and is probably as good an all around formula as there ever was. However, it has the one. drawback in not being as simple as it should be, unless the proper weights and measures are used, and in any institution, gallery or laboratory where much photographing is done, the writer has devised a simpler formula which appears to be as good for gas light papers as it is for plates, with the one possible exception that sometimes it has to be diluted a little more than at other times. Weighing is never necessary because the raw materials all come in weighed packages. Distilled water is not necessary under any circumstance, because both Metol and Hydrochinon are antiseptics of the highest order, so that even water containing more than a trace of organic matter can be safely used without detriment. The formula is very simple and is as follows:

This is shaken up and allowed to stand, and when dissolved will keep indefinitely if the cork is tight and if the bottle is full. To have 16 ounce bottles is a very handy thing, and I have

known this developer to keep perfectly fresh for over a year and a half in a glass stoppered 16 ounce bottle. It is always a good thing to grease the stopper with a little vaseline to prevent the alkali from dissolving the glass and cementing the stopper to the neck of the bottle.

For developing plates, this developer can be used full strength and one dozen 61⁄2 x 81⁄2 plates can be developed in 10 minutes with ease.. If the subject comes up too black or white, it is always an excellent idea to have a tray of water alongside of the tray of developer, and when the plate is half developed and shows intensity and hardness, slip it into the tray of water and leave it in there five minutes. It will develop itself very slowly and evenly, and the hardness will entirely disappear.

In black and white objects like the illustration a white dress with black dots and hardly any shadows, the additional water development is of great benefit and advantage. The plates and the gas light prints from which these illustrations were made were both developed with the formula just noted, and the only care and admonition necessary to observe is that with some of the gaslight papers, it is necessary to add more water to this formula.