WHILE the cause of different tones secured on developing-out papers is well known to many photographers, from the number of inquiries received we are led to believe that there are many who do not have a very clear understanding of what developer to use to obtain a blue-black, an olive or a warm toned print.

Different papers vary considerably in the tone of the print produced under normal conditions. Vitava and Artura give olive or warm tones; Azo, olive or black tones and Velox, black or blue-black tones, the color of the print being determined largely by the relation of exposure to development.

A print that has been over-exposed and under-developed tends to have an olive or green tone. Such a print is not necessarily developed a short time but is most likely to be the result of something that has retarded development. An old or weak developer or one containing an excess of bromide develops slowly, and to overcome slow development the print is often over-exposed with the result - an olive or green print. A cold developer or one containing a small amount of carbonate or weak carbonate will produce the same result.

Aside from the nature of the paper itself, then, anything that retards development will cause the tone of the print to lean towards the olive or green.

On the other hand, a print that has been correctly timed or slightly under-timed and fully developed will have more of a black tone and the longer the development the colder will be the tone. So that whatever has a tendency to speed up the action of the developer induces short exposure, full development and cold tones.

For this reason developers intended to give cold black tones usually contain more carbonate than sulphite. The carbonate is an accelerator and makes the developer work faster. Such a developer formula will be found in the directions for Bromide and Velox papers; also in the Azo direction sheet under the heading, "Commercial and Amateur Printing." There is also a formula for a portrait developer which produces softer results and warmer tones.

In addition to the increase in carbonate in the cold-tone developer it will also be noted that there is a smaller amount of bromide, only enough being used to protect the print from chemical fog.

The portrait developers can always be distinguished by the fact that they contain less carbonate than sulphite and a fair amount of bromide, so they develop more slowly and give warmer tones.

In the "Vitava and Artura" booklet the formulas are given in two and three solutions. In the Vitava formula, the No. 1 solution contains more sulphite than carbonate while the No. 2 solution contains carbonate alone. This makes it possible to vary the carbonate at will.

The Artura Stock Solution calls for three solutions, the No. 1 containing less carbonate than sulphite, the No. 2 containing no carbonate at all and the No. 3, carbonate alone.

The normal developer is made from No. 1 solution; the soft developer from No. 1 and No. 2 solutions; the developer for Carbon Black, used for enlargements, from No. 1 and No. 3 solutions and the developer for Artura Non Curling, which is a commercial paper, from the No. 1 solution without the addition of bromide that is recommended for the portrait developer. And it might be added that this last developer is the one that will give the best cold black tones on Artura Iris paper.

Therefore, to obtain warm or cold tones use the formula recommended. If for any reason it is seen fit to alter the published formulas it must be borne in mind that they do not permit of much variation. Radical changes in the proportions of chemicals used are very likely to upset the chemical balance of the developer, produce chemical fog and in other ways affect the quality of the prints.

Weak or impure chemicals are dangerous for the same reasons, so for the best results, choose the most suitable formula, pure chemicals and follow the manufacturer's instructions.

A good advertisement is not one that tells people how good a photographer you are - it is one that makes people want photographs.

Photograph By Winemiller & Miller, Inc., New York.

Photograph By Winemiller & Miller, Inc., New York.

This photograph of the Japanese Tea Garden shows what can be done with patching. The Japanese girl and the girl to the right are in one photograph. After taking several snaps of this subject, the girl at the left was taken out of one photograph and inserted in this. The scenic background was painted in.