How to Choose Film? Learn about Types, Sizes, and ISO in One Article!

Film, derived from the pronunciation of the English word "film," also known as "film negative," mostly refers to photographic films used in photography to record images through an imaging medium such as a camera. The most common type of film is the light-sensitive emulsion-coated film, which can be in a strip or sheet form on a gelatin base. The light-sensitive layer contains tiny light-sensitive crystal particles, whose structure changes due to exposure. When taking a photo, the light beam of the image passes through the lens into the camera and is projected onto the film. The crystal particles undergo a chemical reaction due to light absorption, forming an image that has not yet been seen. These images need to undergo "development," which is usually called "processing," before they can become visible images on the photo.

Film can be divided into black and white film and colour film. As the name suggests, black and white film refers to film that only has black and white colours after processing. However, black and white films can be further classified into panchromatic films, orthochromatic films, panchromatic separation films, blind separation films, infrared films, and X-ray films depending on the light's sensitivity. Colour film refers to film that can show multiple colours after processing.

Film can be divided into positive film and negative film. The particles in negative film are relatively larger, and the colours are relatively soft. The colours displayed on the film are the opposite of the colours of the actual objects. They require a "reversal" process during processing to produce colours that are the same as those seen by the naked eye, making it the most common type of film. On the other hand, the colours in positive film are the same as those of the actual objects, and the colours are bright, the contrast is high, and the details are more delicate. However, positive film requires very high exposure accuracy, and inaccurate exposure can affect the image quality of the photo. The processing procedure and temperature control for positive film are also more stringent. Black and white films and colour films also have positive and negative types.

On the other hand, 120 film is larger in size, with a photosensitive area of 56 x 56mm. It can be used to capture different format sizes and exposures but is not suitable for use with compact cameras and requires a medium-format film camera. Before the 1960s, 120 film was widely used, but it gradually became less popular as the quality of lenses for 135 film cameras improved and became more affordable. In the 1970s, the market penetration of full-automatic colour cameras using 135 film increased, eventually replacing 120 film in the non-professional photography market.

As for 110 film, its size measures 13 x 17mm, with lower photosensitivity with ISO values of only 100, 200, and 400. There are also larger-sized films specifically for shooting commercial advertisements or large posters.

Like in digital photography, ISO in film photography refers to sensitivity to light. Different films have different levels of sensitivity to light. Each film's ISO value is provided by the film manufacturer and indicated on the packaging. The higher the ISO value, the more sensitive the film is to light, which means it can capture images in darker environments. In addition, the camera's ISO setting should match the ISO value of the film used to produce a properly exposed photograph.

The most common film ISO values on the market are 100, 200, and 400. For example, when shooting on a sunny day with ample sunlight, ISO 100 film is sufficient. However, when shooting in cloudy, low-light, or indoor environments, ISO 400 or higher film is needed to capture better results.

In addition to choosing a brand, you can also consider using black and white or colour film for shooting. Although black and white photos lack colour, they are not just black and white, but are composed of black, white, and different shades of gray, which provide rich levels and can capture images with strong lines to highlight the subject of the photo. Colour film can capture more environmental information at the time of shooting, such as the lighting and atmosphere, adding emotion and details to the photo, presenting a more rich image and complex visual effects.

As mentioned earlier, different ISO films should be used in different shooting environments. Therefore, when choosing a film, you need to consider the shooting environment and weather. If you want to reduce the chance of photos being too dark or blurry due to insufficient environmental lighting, you can choose a higher sensitivity ISO 400 film.

One thing to note is that most common film cameras on the market use full-frame 135 film, while cameras that use medium-format 120 film are less common. Therefore, when choosing a film, you should first confirm the film size used by the camera.

For film photography enthusiasts, photos taken with film are more textured than digitised photos. In fact, developed film photos can also be digitised, allowing them to be permanently saved and viewed on electronic devices, and shared with family and friends through shared albums.

Learn more about Capture.HK's photo album digitisation services now!

Sources from:

• Film - Wiki
• Retro Film Camera Recommendation! 4 types of film cameras / beginner's guide / precautions explained in detail - Pinkoi
• [Film Photography] 135, 120 or 110? - Dcfever
• Beginner's Film Tutorial - Filminglab
• Understanding Film - Introduction (Part 1) CiHqCz-BFFjBAGx2mHtg/edit - Dcfever
• [Stills photographer and producer] Top 10 Film Recommendations for 2023 - mybest