While most photograms are made with standard black and white photographic paper, the Photogram is a process that lends itself to experimenting and in terms of materials, the limiting factor is only one's imagination.

Film:
While images can be made on any type of film, film format or size is an issue when making photograms. Photograms can be made on lengths of 35mm or 120 roll film but the width of the film is a limiting factor. Sheet film, say 4x5 works well and then the processed negative can be enlarged up to any size in the usual manner. 8"x10" sheet film offers 4 times the area of 4"x5". Generally, using film is more difficult in that more care is needed with handling that the surface is not damaged and at the processing stage. It also requires more equipment like processing tanks etc.

With most film, because it is sensitive to all light, it is more difficult if not impossible to see where and how the objects are placed on the paper. It becomes a random and tactile experience placing the objects on the paper, but the objects can be placed on a sheet of glass in the light and the paper slipped under in darkness for the exposure.

However litho film can be used to make photograms in the same manner to standard black and white paper. (Most Litho film can be used in a red safelight)

If the photogram made onto a piece of film is enlarged on to a piece of black and white paper the final image would become positive.

Black & White or Monochromatic Films

A photogram exposed onto a piece of 8x10 Black & White Negative film

The photogram negative printed into a sheet of paper from the same sheet of 8x10 negative film

Colour film.

If however transparent colour positive materials were used i.e.. Ilfochrome or sheet film like Ektachrome the image can be printed onto negative colour paper to produce an enlarged colour reversal of the original objects placed on the film.

However, remember there are some
other factors that come into play: colour neg paper has an over all blue cast built in to compensate the tan base or orange colour that is inherent in a colour neg. Because the red transparent object like a bottle does not have this there would be a colour shift in the opposite direction of the tan base which might have to be allowed for by altering the colour filtration in the enlarger. Putting a clear piece of colour film with the orange base on it in the neg carrier is also a way of equalizing this shift.

Top* Agfa Optima 4x5 colour neg film Center* Agfa RSX 4x5 Colour transparency film Bottom*Agfa APX 4x5 100ASA B&W negative film

Photogram on full length of 120 negative roll film

Details: Photogram on length of 120 negative roll film

Photogram on 4X5" Transparency Ekatchrome film

 

Calculating Exposure for photograms on Film.

As most film has to be handled in total darkness and takes sometime to process, it can be useful to devise a method of calculating an exposure.

I have devised the following method that works well:

1. Lift the head of the enlarger to cover the entire base board of the enlarger. (Because the sheet of film has to be placed in the dark it is wise to make sure the area where the light falls is large enough.)

2. Set the filtration of the enlarger to the desire setting, and set the aperture to about f8.

3. Using a hand held light meter with the sensor set to read incident light, point the meter directly towards the light source. You might find this gives a reading of say EV 3.

4. The time for the exposure should be read on the scale using an imaginary aperture of f1. ( This assumes there is no restriction to the light falling on the base board at all.) We need to set the sensitivity of the film. So with an Ev of 3 and 100 ISO Film we would have a shutter speed of 1/8 sec. or 0.125 on the enlarger timer.

5. However, because of the nature of what light meters read, transposing this reading to an exposure time would produce an image with the darkest tone at mid grey, and not give a dense black.

5. Applying the zone system, to give a maximum black, the reading would have to be shifted back by about 4 stops. So 1 extra stop would be 0.25 sec, 2 stops would be 0.5, 3 stops would be 1.0 seconds, 4 stops would be 2 seconds.

So using the enlarger with the aperture set where the light meter reading was taken the exposure would be about 2 seconds.

Enlarged prints can be made from photogram negatives.