If every photographer used distil led water and pure chemicals in making up his developing solutions, the formulas published by the manufacturers of plates and papers would be found to work with greater general satisfaction than any formulas the individual worker might be able to substitute.

Since distilled water is not generally used, local conditions often make it necessary for the photographer to alter the formulas recommended to suit local conditions. It is not necessary, however, to discard a tried formula simply because it does not produce the desired result under widely differing conditions. There may be exceptionally good points about a developer, that can be very readily used if a slight modification is made to allow for a condition of the local water supply.

Every man who handles sensitive products or has charge of men who do the actual handling, should have a thorough knowledge of the action of the chemicals used in a developer and should be able to balance them so that the best results may be secured regardless of the water used.

It is reasonable to believe, even against your own judgment, that the formula recommended by the manufacturer is best for his product or it would not be recommended. If it doesn't produce good results in your hands it is probably because the water you use is not pure, your chemicals are not properly compounded or not of proper strength.

If the water you use for making up your developing solutions is strong in alkali and you are using the amount of carbonate of soda recommended, it is plain to see that your negatives will have too great contrast and will be blocked up in the highlights. Don't let a workman condemn and discard a good formula on this account. Have him use his head and reduce the amount of alkali (carbonate of soda) until the developer is properly balanced, then make the necessary change in your formula so the trouble will not occur again.

On the other hand, if a poor grade of carbonate is used and sufficient developing energy is not produced it may be necessary to increase the amount of carbonate specified in the formula. C. K. Co. Carbonate of Soda is approximately 98% pure and when other sodas are used it is usually necessary to increase the amount to secure the same result.

An excessive amount of alkali, usually resulting from water heavily charged with some form of alkali, causes a developing agent such as Pyro to act too energetically with the result that highlights are over-developed before the delicate gradations of the shadows are normally developed. Blocky is the term usually applied to such results. The same rule applies to the color of a negative, especially if it is a Pyro developed negative, and we believe most photographers have reached the point where they are willing to admit the contention of the manufacturer that there is none better.

Once the proper degree of contrast has been secured to show all the steps of gradation from highlight to shadow, the color of the negative may then be varied to give proper printing quality.

A negative should have some color to have good printing quality, and if the negatives from the standard formula have too much color increase the amount of sulphite of soda until the color is reduced sufficiently to give you the desired result. Don't think of the beauty of the negative when you are reducing color, but judge the proper degree of color by the quality of the print the negative produces. Too many dark-room workers have the idea that if a negative looks good it will print just as good as it looks - but the printer knows better. Give the printer the quality he asks for and he will usually produce more quality in the print than you can detect in the negative.

Even a Pyro developed negative will give too little color with an excess of sulphite, so there is such a thing as going to extremes. A slight alteration of the formula given by the manufacturer is all that is necessary except under very unusual conditions.

Sulphite of soda absorbs oxygen and by so doing prevents too rapid oxidation of Pyro which gives the stain or color so desirable when properly regulated. Sulphite of soda crystals deteriorate very rapidly when exposed to air. They are changed to sulphate as they dry out and when sulphate is present the preserving action is reduced to just the extent that the sulphite has deteriorated. Dry or anhydrous sulphite does not deteriorate so rapidly but its condition is more difficult to determine. The safe rule is to buy the tested chemicals in an original package, and keep it airtight and free from moisture.

There is one other ingredient of the developer of which we wish to speak in this article. As a preservative of Pyro the use of Metabisulphite of Potassium or Bisulphite of Soda prevents oxidation to such a degree that this objection to an otherwise perfect developer is practically overcome.

A stock solution of Pyro in which either of these preservatives is used will keep for an indefinite time if ordinary precautions are observed.

Local Conditions StudioLightMagazine1918 30

FROM A PORTRAIT FILM NEGATIVE

By The Luck Illustrating Co. Cleveland, Ohio

Exhaustive experiments have proved that Pyro will undoubtedly give the finest printing quality obtainable in a negative and if reasonable modifications are made as suggested, where local conditions seem to make the manufacturers' formulas unsuited to their products, they will be found, on the contrary, to be productive of better quality than any formula of the photographer's own devising.

New Mounts

You may be making negatives second to none and your prints may render to the full everything you put in the negative, but the salability of the pictures will still be influenced beneficially or the contrary by the setting or dress in which they are offered to the prospective purchaser.

The 1918 styles of the Canadian Card Co. are giving a clean-cut contradiction to the ancient belief that imported mounts were necessarily the best obtainable.

In design, in finish and in quality of stock they will win the approval even of the sternest critic, for they have been favorably passed upon by the stock-house boys who are oftentimes harder to suit than their customers, which is as it should be.

Prices are reasonable and service prompt.