While practically everyone who has tried the tank is charmed with its simplicity and certainty, there are a few photographers who express themselves as not wholly satisfied, and some others who are sceptical as to the validity of its claims. The second class are mainly composed of practitioners who have met with users whose experience have not been quite happy.

Let us see why. Tank development may be said to come both as a revelation and a revolution to stereotyped workers. But its foundation is built upon scientific facts, and so is past argument. Every contingency has been foreseen and solved, and if used exactly in accordance with the direction, the very best results are assured.

The Eastman Plate Tank is constructed correctly. The nickel plating ensures that the chemicals used in developing do not suffer by contact, but the surfaces of the tank and its cage must be kept clean. Stains and streaks nearly always mean a dirty tank. Corrosion must be strictly guarded against, and this can only be done by careful cleaning and thorough drying after each time of using.

Transparent spots are another trouble occasionally met with. This is usually due to the ad herence of air bells on the surface of the plate. If the tank be thoroughly shaken up when the plates are first immersed, all the air will be brought to the surface. Sometimes, but very rarely, the water supply is at fault. Boiling and allowing to cool is the treatment here indicated.

Insufficient density is caused by either too low a temperature or inaccurate solutions. The careful use of a thermometer is imperative, while the use of reliable chemicals, accurately compounded, is no less necessary.

Kodak Tested Chemicals, carefully weighed, are a sure guarantee for certain results.

The development of dry plates is caused by the contact of an active developing agent with such silver salts as have been acted upon by light.

If a developer so balanced as to be vigorous and strong is used, it will attack the exposed silver rapidly and darken it quickly, forming a coarse grained deposit of silver. The image thus formed will not possess full delicacy and detail. If a developer so balanced as to be slow in its action is used, it will search out and produce an image of fine grain with full delicacy and detail.

Judged by results, the slow working developer has every advantage over the stronger developer, but in darkroom development there are two reasons why the slow working developer is not practical. First, the length of time required to develop has made the work of darkroom hand development tedious and slow. Secondly, the length of time required to carry the development to completion with an extremely slow working developer, makes it necessary to use caution as to the strength of the darkroom light, or fog will result. This condition makes a quicker developer the best choice for hand development, although the quality of the finished negative is not entirely satisfactory.

There is now a device in general use that makes it possible to realize all of the advantages of slow development without any of its disadvantages - a device that makes it possible to produce negatives of fine grain with an absence of red-light fog - a device that eliminates the tedium of hand development - eliminates the probability of scratches, finger marks, and frills caused by handling, and this device is the Eastman Plate Tank.

With the proper use of the tank good results are assured. and the work of plate development is made easier, and at the same time better. Use the reliable, conveniently constructed Eastman Plate Tank.

Our advertising cut service will help you. See page 22.

From An Artura Iris Print By Hubert Bros. Buffalo, N.Y.

From An Artura Iris Print By Hubert Bros. Buffalo, N.Y.

From An Artura Iris Print By Hubert Bros. Buffalo, N. Y.

From An Artura Iris Print By Hubert Bros. Buffalo, N. Y.