Digital photography is still the go-to medium for capturing images and has been for well over two decades. That is not to say that there aren't still many who prefer the more hands-on approach. These diehard fans still work with photographic film.
At the height of film photography, there were many different types that one could choose from. Each had its advantages and uses. Sadly, many have disappeared, yet some have survived, and others, happily are making a comeback.
cover by Jr Korpa
All Photographic Films Are Equal. Some Are More Equal Than Others
All photographic film have commonalities. For one, they are all thin strips of cellulose, coated in photographic emulsion. Gelatine holds the light-sensitive silver halides which makes the capture possible. The film goes into the camera, either as a roll (35mm, medium format) or a sheet (large format). It is then exposed through a small hole (pinhole or lens aperture) entering the camera body.
What makes the film different is the chemical makeup of the emulsions. Silver halides are what capture the light, yet the other elements of the film are what give the analog film its characteristics.
Photographic Film: The Negative
A negative is a reversal of what is being captured. For example, black areas on the film are white areas captured mise en scene. An enlarger prints, where the scene is again reversed. The darker areas hold back the projected light, minimalizing the exposure.
Color
The color-negative film is made from layers of color emulsion and filters. These divide and capture the light in magenta, yellow, and cyan. Within each of these layers, silver halides capture the light. The three color layers work alongside dye couplers. They help to create the colors when developed (oxidization of silver halides). The bleach and fix bath at the end of the development stage removes the silver, making the color film grain-free.
Color photography was a little more complicated to develop at home than black-and-white negative film. Press kits were used to process the different color layers. Since its start in 1935 with Kodachrome, there have been many different processing methods for color negative film. Now, only C-41 is the standardized way to process, which is possible to do in an hour (dry to dry).
Color negatives have many different film speeds, the negatives of all (except Portra 160) have an orange cast when developed. This combination of mask dyes helps against color errors when printing. The analog enlargement process works around this for physical prints. Yet needs accounting for when digitalizing the negatives. There are many stops of forgiveness with color film, allowing for correcting an imperfect exposure (over or under).
Black and White
Like color negatives, black and white film has many parts. A backing layer, film base, anti-halation layer, emulsion layers, and a protective coating make up the film. When developing black and white, the developer changes the silver halides into silver particles. As black and white don’t use color dyes, the grain patterns are slightly different. They also have a wider latitude (far more forgiving) and longitude (last longer without issues of fading).
B&W negative film is easier to photograph with, as less importance is placed on color hues and tones from lighting sources. It is also easier to develop at home. Doing so allows more control over the processing and the resulting levels of contrast, grain, and exposure.
NB: It is possible to process B&W film in color chemicals
Photographic Film: The Positive
A positive is the opposite of a negative. What you see on the film is how it looks in reality, at least, in terms of dark areas are dark and light areas are light. These were often used in slideshows and presentations using a Kodak Carousel.
Color
Color transparency film is almost identical to color negative film – it can have as many as 20-30 layers and still only be a few microns thick. The difference is positive film uses an E6 development and an extra reversal step which turns the negative into a positive. The biggest difference is that the slide film can be held up to show a true-to-life ‘positive’ scene.
With transparency film, there is little to no forgiveness in the latitude of exposure. Slides need to be spot on for Carousel slide show presentations, where a stop of play is possible if the positives are digitalized. Color-positive films were the standard for professional and commercial photography until the 80s. The most famous was the Kodachrome due to its fine grain and vivid colors.
Black and White
Black and white transparency film is much rarer than the color counterpart. Yet there are still a few options available; namely Afga Scala & Fomapan 100 R. Black and white positive film is more complicated to process than black and white negative, yet still possible at home.
Photographic Film: Less Common
Negative is currently the most common type of photographic film, with positive slide film running behind. Here are some photographic films that are no longer needed due to the possibilities of digital photography.
Orthochromatic Film
Like many terms in photography, Orthochromatic comes from Greek; Orthos for right and Chroma for color – a black and white film. It was first created in 1873, with an emphasis on silver halides, which are naturally sensitive to blue wavelengths, between 400 and 600. This was a major reason why skies in early photographs were white.
With the addition of organic coloring, sensitivity to yellow and green is possible. The film is blind to red light, so all red items would show up on the negative as black. The benefit is the film could be developed and processed using red light without affecting the film. A blue filter would also render red items upon the film. The film is super fine, with an ISO of approximately 25.
Panchromatic Film
Pan means all or wide and Chroma for color meant that the film is sensitive to all colors. Its sensitivity is slightly reduced for blue and green wavelengths - up to 660/750 nanometres for super-panchromatic. This film, produced around 1906 was an improvement on the Orthochromatic counterpart. It allowed the halide sensitivity to red and green wavelengths.
The film has its use placed in warm-temp light, where a yellow or orange filter could emphasize the details in blue skies. The best examples of Panchromatic photographic films are Tri-x 400, Kodak TMAX, Agfa APX, Ilford HP5, and Ilford FP4. One issue that photographers found, was the film winding numbers could expose upon the negative through the red window on the back. This was especially true with medium format cameras.
NB - Orthopanchromatic or Rectepanchromatic had a reduced sensitivity in the red spectrum
Infrared
Infrared film is a panchromatic photographic film, sensitive from ultraviolet to red wavelengths. The name comes from the fact that the film can reach sensitivity to the infrared range, which was not possible by other films. It is possible to manipulate the light hitting the film using filters.
Black and White Infrared
The most surprising thing about the infrared film is that it records heat radiation. This is a film best used around spring or early summer as it better defines shadows under trees and around vegetation. This is due to the film picking up on the heat being released by plants during photosynthesis, increased in these seasons.
For further use, a black filter (actually dark red) blocks out all visible light and only lets infrared through. This creates very strange and eerie negatives, where green items or areas show as overexposed white. Blue areas, such as bodies of water would show as black, whereas landscapes would show the most contrast.
As the infrared film has no anti-halation layer, it results in increased light. This layer usually reflects back towards the light source, so without it, more light hits the film base. This creates haloes around the highlights, making it easy to overexpose. It also allows light leaks, so film loading needs a pitch black space.
Colour Infrared
Color infrared film is different than the black and white sibling as it captures the red spectrum in color – surprise surprise. Instead of turning vegetation and foliage white, it turns red and pink instead. Kodak Aerochrome III is the most famous color infrared film. Blue areas like water still appear to be black. A yellow/orange filter is necessary to block all blue light, giving the film its deep red colors.
The purpose of this film wasn't for creative reasons. It was used over the last 100 years, for surveying, and military applications. Originally developed to see better through large green areas during WWI. In the 1930s, it was then further adapted for use in astronomy. Since then, aerial surveying applications used it to capture and report on vegetation and forests.