This section is from the "Studio light a magazine of information for the profession 1923" book, by Sara F. T. Price. Also see Amazon: Studio light a magazine of information for the profession 1923.
There are a lot of people who own and operate two cars, a small town car for ordinary use about town where speed and power are not so essential as reliability, and a high powered, high speed car for touring and other special uses.
A great many portrait photographers who use Portrait Film prefer Par Speed for all ordinary purposes - use Par Speed whenever conditions permit, but who would not be without Super Speed for the unusual condition - for the emergency when one must have exceptional speed or fail to deliver the goods.
By ordinary conditions we mean normal conditions, in the studio or out, when there is suf-ficeint light to enable you to make short exposures with a fast emulsion such as you will find in Eastman Portrait Film, Par Speed. This film has as fast an emulsion as the fastest portrait plates - it has been used for years as the standard fast material for all kinds of portraiture as well as for many kinds of commercial work.
If you will refer to "Film Speeds" in the Eastman Professional Film Booklet you will find a table of approximate relative speeds of the various brands of Professional Films. We have assigned a speed of 100%, or Par Speed to the regular Portrait Film emulsion and have rated other films relatively slower or faster using 100% as a base.
By this method of rating the comparative speed of Portrait Film, Super Speed is 200%, the most remarkable speed ever developed in a negative making material that is specially suited to portraiture.
You know what can be accomplished with Par Speed Film. If you have never used Super Speed Film you can at least imagine what can be accomplished with this Super Speed emulsion. If the light is weak and you must get results or, if the light is good but you must make exposures that would not be sufficient for Par Speed Film, Super Speed will turn the trick and save the day for you.
FROM A PORTRAIT FILM NEGATIVE
By Wm. S. Ritch
New York City
But even Super Speed Film has its limitations. One must not expect the impossible. As a matter of fact, however, where Super Speed Film is used exclusively it is more often over rather than under-exposed.
This is largely due to the fact that the user does not take note of the very important difference in developing Super Speed Film.
This very fast emulsion builds up its density and contrast somewhat slower than the regular speed emulsion, so that if a Par Speed and a Super Speed exposure are developed for the same length of time in the same developer, the Super Speed negative will not seem to be faster because it has not been fully developed.
Allow it to develop fifteen per cent longer than the Par Speed and its quality will immediately be seen. If the Par Speed has only received one-half the exposure it should have, the Super Speed will develop to normal density and retain all the portrait quality of a properly exposed film.
One can readily see what this reserve speed will mean to the man who must get results regardless of conditions of light and possibly with exposures that would be too fast for ordinary films or plates.
In the studio such conditions are frequently encountered and there should be a supply of Super Speed Portrait Film on every dark-room shelf for the emergency when it arises.In home portraiture there is even greater need for this fast film. Some workers will not use a slower film - insist on Super Speed at all times - and while this may not be necessary there is the argument that many unusual pictures are often secured because the confidence in Super Speed leads one to attempt and succeed where other materials would fail.
We have not even touched on the uses of Super Speed Film in commercial photography and we believe it is being used as extensively in this work as in portraiture. This may be because the commercial worker has even a greater use for a fast film. It is a fact that he encounters every imaginable condition of light and must often provide his own means of artificial illumination. If he can produce a result with Super Speed Film with half the amount of lighting equipment that would be necessary for Par Speed Film or a plate, of course this additional speed is to his advantage.
But there are times when artificial light can not be used and only a fast material can make any result worth trying for, and it is under such conditions that Super Speed Film has proved its greatest value to the commercial photographer.
If you are not already a Super Speed Film enthusiast you will be if you give it a fair chance to help you broaden your photographic opportunities.
FROM A PORTRAIT FILM NEGATIVE
By Wm. S. Ritch New York City