IT is ten years since Portrait Film was introduced to the professional photographer and in all of that time there has not been the slightest falling off in the growth of its popularity. In fact its record of performance has been so notable that its use has spread to the far corners of the globe and everywhere it has overcome all prejudice and by the sheer weight of quality has won its way against all competition where superiority of results has been the deciding factor.

It is not advertising that has caused film to so largely displace glass plates in professional photography. Advertising doesn't create quality - it only tells of it. And many of the enthusiastic users of Portrait Film have told us we have been too modest in our claims for film quality. We will admit that we have not said as much about film as the photographers who use it, but after all the satisfied user of a product is its best advertisement.

For ten years Portrait Film quality has spoken for itself. Film results have made new film business, and with the introduction of Commercial Ortho, Commercial, Process, Commercial Panchromatic and finally the greatest film of them all, - Portrait Super-Speed, the progress of film has assumed the proportions of a tidal wave.

There could be and there is but one reason for such a phenominal success - quality. To produce an ideal negative necessitates the use of a medium that is capable of registering correctly every tone of the subject and such a medium is found in Portrait Film.

Ten Years Of Film Accomplishment And Success StudioLightMagazine1923 74

PORTRAIT FILM NEGATIVE, VITAVA PRINT

By Fernand de Gueldre Chicago, III.

Portrait Film has the capacity of rendering an enormous range of tones both in the region of correct exposure and under-exposure, by which we mean that the steps of gradation, even in the shadows, are very even so that if this gradation were represented in the form of a curve it would be found to rise steadily from the very beginning of exposure.

This indicates that even with very contrasty subjects it is not necessary to over-expose the highlights in order to pick up detail in the shadows. It is also an indication of the very great latitude of Portrait Film. Demonstrations have been made from Film negatives having a variation in exposure in ratio of from 1 to 80, the negatives having been developed in a tank for a fixed time at a given temperature to produce uniform contrast. Their printing value was practically identical. Because of the great variation in exposure, of course, there was considerable difference in their density but the two extremes of exposure produced excellent prints.

This demonstration which was made before a photographic society in England was a most unusual test of latitude and showed conclusively the wonderful reproductive capacity of Portrait Film.

There is another very essential Film quality that has an important bearing on the ability of Film to reproduce correctly the tone values of the subject. This is the non halation properties of Film.

The long scale or gradation of Film, which makes it unnecessary to over-expose highlights to pick up shadow detail, helps to reduce one cause of halation. But the greatest cause of halation is the thickness of the support on which the emulsion is coated.

Reflection from the back of the glass is the greatest cause of halation when plates are used. And this is overcome by the very thinness of the support for the Film emulsion. There is practically no halation in Film negatives.

It may readily be seen how this lack of halation is an aid to correct reproduction. Halation is not confined to large areas of light. It is most noticeable when it occurs around windows or other large masses of light but it is just as destructive when it appears in the very small areas of delicate highlights in which one sees threads of shadows but is unable to reproduce them if halation is present to spread over these shadows and destroy them.

Film makes such reproduction possible. Film negatives have that very desirable brilliance in highlights and halftones because of the lack of halation. It is really a new quality that has come to be associated with Film results because it is due entirely to that physical property of Film that removes the primary cause of halation.

Ten Years Of Film Accomplishment And Success StudioLightMagazine1923 76

PORTRAIT FILM NEGATIVE, VITAVA PRINT

By Fernand de Gueldre Chicago, III.

We have not done credit to Portrait Film results however without the mention of the comparatively new Super Speed. This is a very unusual and remarkable material for portrait work because it has all of the qualities of the regular Par Speed emulsion combined with extreme sensitiveness.

Super Speed is the only expression that will do it justice and it fully lives up to its name. Already we find Film users who have found its speed and quality sufficient reasons for them to change to the exclusive use of Super Speed.

We are not suggesting this, however, for Par Speed has every desirable quality of a portrait material and is as fast as the fastest portrait plates. But Super Speed has this one advantage of speed and it is indeed a great advantage when conditions of light are poor, when children are restless and must be caught with short exposures or when it is necessary to work under any conditions which would ordinarily mean failure with ordinary exposures.

There is only one difference in the manipulation of Super Speed Film that is essential to results. The nature of the emulsion is such that it requires 15% longer development, but this is only a detail of manipulation. Of course its extreme sensitiveness also requires that it be handled with reasonable care to prevent fog from any unsafe light, but this would be true of any extremely sensitive material.