This section is from the "Studio Light Incorporating The Aristo Eagle - The Artura Bulletin 1922 " book, by Aristo Motto. Also see Amazon: Studio Light Incorporating The Aristo Eagle - The Artura Bulletin 1922 .
WHEN I was serving my ap-prenticeship in a photographic studio our printing room was on the roof and the head printer thought it a fine joke to have me carry a lot of printing frames up to the front of the building towards evening where, as he explained, the light was stronger because it was nearer the sun.
I soon learned better, but when I began working in the skylight room I thought the photographer was trying to play another joke on me when he tried to teach me that the light was stronger next to the skylight than on the opposite side of the room.
But one day I learned that the skylight itself was the source of light and that light diminished in inverse ratio to the square of the distance from the light. And when I got that through my head and knew what it was all about I found that what I knew to be a fallacy regarding the light on the roof was really true of the light coming through a window or a skylight.
A great many photographers do not take advantage of the light they have, thinking, possibly, that it is necessary to get in a far corner of the room, or at least a considerable distance from the light, to get softness.
The result is long exposures and flatness when the thing to be desired is short exposures and roundness.
Work close to your light - as close as you can and still get diffusion, and this is easily done at four or five feet from the light.
The modeling of your light will be better and more easily controlled, your ground-glass image will look round and will stand out from its background rather than sink into it and, of very great importance, you can materially reduce your exposure and still have fully timed negatives.
It is quite important that you make the sitting for a photograph as little of a trial to your customer as possible. And long exposures will not add to your popularity as a photographer.
Do everything in your power to make exposures short, without under-timing, of course, and you will find that working close to the light will materially help matters.
With the proper balancing of your light you can produce either a low or a high keyed lighting without unnecessarily increasing exposures. Working at eight feet from your light your exposures will need to be just about four times as long as if you work at four feet from the same light.
Possibly you can't work as close as four feet, but whatever the distance you will find the rule practically correct. Technically, the rule applies to what is known as a point source of light, but as most workers use only a portion of their skylight or a fairly concentrated artificial light source, the light diminishes in strength very rapidly as you work away from it. Make use of all of your light, use Super Speed Film and a fast lens and you will find the short exposures this combination enables you to make will decrease the number of your failures, enable you to secure better expressions and give your sitters a more favorable impression of your methods of photography.