Film is made of a light sensitive emulsion, which is gelatine that consists of silver halide crystals; this is coated on a plastic base that is made of cellulose acetate. The emulsion reacts to chemicals during the several processes to form an image.
Formats and different film types
There are various different film formats that were introduced to the world of photography, the main formats are:
Large Format/ sheet film (4x5”, 5x7”, 8x10” etc)
Medium Format (6x6”, 6x4.5”, 6x7”, 6x9” etc)
For large format film, the size that is most dominant is 4x5” as it is widely used to take landscape photos. Mostly old-fashioned cameras are used to take large format images.
Medium format film is used for partially any shooting form, for landscapes and sports etc. It is a well-used format and gives a decent quality image. The cameras used to take medium format images are Hasselblad, Leica, and Bronica etc.
The most popular film format is 35mm as the cameras that take images at that format are portable and the most compacted, easy to use film cameras.
The three different types of film are:
Colour negative (print) film
Each film requires to be chosen based on the lighting scenario the image is taken in and this is done by choosing the film speed – ISO rating. For example, if the images are to be taken outside, a suggested film speed of 400 is to be used as opposed to a film speed of 100; this is because the ISO rating determines how sensitive the film is to the light.
Cross Processing is processing photographic film in a chemical solution used for a different type of film. It is used to create different effects such as sepia etc. In a way, it is manual filtering. The two main processing chemicals used are:
C-41 chemicals are used to process positive colour reversal film on a transparent base, resulting with the image coming out stronger, creating a higher contrasted, negative image.
E6 chemicals are used to process colour negative film, creating a soft, grainy effect. It is processed on an orange base, which is normally processed on a colour negative. Different types of film brands and emulsion will give different alterations in contrast and colour bases.
Overall, cross processing is used in order to enhance the colours, contrasts and saturation in a creative, unique way. It allows the photographer to experiment with different chemical processes using a range of film and film brands to create an image with a certain effect.