You never heard of a photographer using an ounce Pyro can to measure an ounce of soda. Certainly not, for such a proceeding would be so palpably wrong that it would not be thought of. But are you absolutely sure you weigh your chemicals correctly - even with the accurate scales you may have for that purpose?

We take up this subject of weights because we have learned of several cases, and there are probably many more, where photographers have thought they were using Avoirdupois weights but found they were using Apothecaries'. And it does make a great difference.

All our formulae for plates and papers are based on Avoirdupois weight, and all our chemicals are sold by Avoirdupois weight. Make up one of these formulae by Apothecaries' weight and you are missing the mark of those who balanced the chemicals in that formula to give the best possible result.

One pound, Avoirdupois weight, contains 7000 grains, while one pound, Apothecaries' weight, contains 5760 grains, a matter of 1240 grains difference in a pound.You can readily see that this would make a great difference in a formula. But in the ounce - the difference is the other way.

The Avoirdupois ounce contains grains, while the Apothecaries' ounce contains 480 grains, making a difference of 52 1/2 grains. The grains are the same in either case, but if your formula calls for ounces and your weights are Apothecaries', you are using 52 1/2 grains too much in each ounce.

If you use an original 1 ounce package of a chemical, that ounce will be right and the ounces you weigh will be wrong.

The only sure way is to have your weights tested and be certain they are Avoirdupois. I have known photographers who had the druggist weigh their chemicals to be sure of having them right, when they were really doing the very thing they should not have done. The druggist always uses Apothecaries' weights.

All our formulae are based on Avoirdupois weight, as per the table below, and all chemicals for photographic use should be so weighed to produce the chemical combinations in proper balance as intended by the manufacturer.










437 1/2

It costs no more to be certain. Specify "E. K. Tested" in your next chemical order.

When Is An Ounce An Ounce StudioLightMagazine1914 91


By Gerhard Sisters

{Of the Women's Federation)

St. Louis, Mo.

When Is An Ounce An Ounce StudioLightMagazine1914 92


We make but one condition in our offer of cuts for the use of photographers.

It is obvious that two photographers in the same town would not care to use the same cut, and we are therefore obliged to limit this offer to one photographer in a town. It will be a case of first come first served. The first order from a city will be promptly filled. Succeeding orders (if any) will necessarily be turned down and the remittance, of course, will be returned. It is also obvious that we cannot, on account of the cost of the drawings, furnish any large variety of cuts at the nominal prices quoted, and therefore can offer no substitute cut. The thing to do is to get your order in first, as it would not be fair to give the man who happens to get in his order early one month, a permanent advantage; we shall book no orders in advance. They must always specify the number of cut wanted. These cuts consist of the illustrations only, thus making it possible for the printer to change the wording or the amount of space to be occupied by the wording if so desired.

E. K. Co.

When Is An Ounce An Ounce StudioLightMagazine1914 93

Let us make your portrait in your own home with all the charm of its surroundings.

Make an appointment to-day.

The Pyro Studio

Quality Portraits Consistent Prices

No. 201. Price, 30 cents.

bulletin: the eastman school of Professional Photography for 1914

St. Louis, Mo.......................April 7, 8, 9

Kansas City, Mo.......................April 14, 15, 16

Wichita, Kan.......................April 21, 22, 23

Little Rock, Ark.......................April 28, 29, 30

Dallas, Texas.......................May 5, 6, 7

San Antonio, Texas.......................May 12, 13, 14

Oklahoma City, Okla.......................May 19, 20, 21

Denver, Colo.......................May 26, 27, 28

Salt Lake City, Utah.......................June 2, 3, 4


Our business was established on a quality basis.

It has grown because we act on the belief that we can maintain our position in the trade just so long as we make better goods than our competitors - and no longer.

Our customers receive the benefit of the most advanced photographic thought of Europe and America. Our American and foreign factories are in constant touch with each other. Each has the benefit of the work and the discoveries of the other. The very breadth of our business enables us to give to each department absolutely the best that the world affords in technical skill and in producing facilities. The man with a new photographic idea turns to Rochester for a market just as he turns to Washington for his letters patent.

Our theory is that we can best serve ourselves by supplying our customers the best goods. Our acts have made this Theory a Policy, for we have not merely the desire to make the best goods but the means of converting that desire into a Reality.

In our thirty years in the photographic business there have been several revolutionary changes. Doubtless there will be many more. Whatever they may be our Policy shall be to furnish (without following every mere will-o'-the wisp) the very best of those goods which painstaking testing shall prove to be of benefit to our customers in the Simplification of Photographic Processes and the Advancement of the Art.

E. K. Co.

When Is An Ounce An Ounce StudioLightMagazine1914 94


By Geo. M. Edmondson Cleveland, Ohio

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Vol.5 MAY 1914 No. 3