There’s a wide range of films available these days, but they fall into just two categories: slides and prints. What you want to do with your images once you’ve developed them will determine which is best for you.
Slide (or transparency) films are usually called something ending in ‘chrome’: for example, Fujichrome, Kodachrome and Ektachrome. They produce a positive image, which can be viewed with a magnifier or placed in a slide mount for projection on to a screen. Projected slides are most impressive and can be shown to both large and small audiences, but they obviously require additional equipment, including a projection screen, and a darkened room for viewing.
Slides have traditionally been preferred by magazine and book publishers, so if you have ambitions in this direction, it would make sense to use this type of film. There are firms in most large towns that process slide films, or you can process them yourself with a minimum of equipment and no need for a darkroom.
The names of print films usually end in ‘color’: for example, Fujicolor, Kodacolor and Agfacolor. Print films produce a negative image, which must then be printed on to photographic paper for viewing. These prints are easy to view and require no projectors or darkened rooms, and can be handed around if more than a few people want to look at them at the same time.
Prints suit most people who just want a photographic record of their dives, with maybe the occasional picture enlarged, framed and hung on their wall at home. There are shops in every high street that will process and print your films for you, and your results can be returned in as little as an hour, although the usual, and more economic, timescale is overnight. You can process print films yourself with the same minimum of equipment needed for slides, but to produce prints from the negatives, you need a darkroom and enlarger.
In recent years, a new type of print-film format has been introduced but, in my opinion, it’s little more than a commercial/ marketing exercise. Known as APS, the film requires a different camera to the traditional type, must be processed on special equipment, yet still produces the same prints at the end.
As with most things today, the advancement of computer technology is having an effect on the world of photography, with the traditional classifications of slide and print film becoming blurred into one large ‘image’ category. Many one-hour processing shops can now scan your negatives and have them made into slides, and vice versa, with very little loss of quality. In addition, magazine and book publishers can work just as well from slides or negatives these days, although it’s still true that they prefer to receive slides, as they can view and assess them more easily.

One often-overlooked difference between slide and print films is that of exposure latitude. Slide film is far less tolerant than print. Under or over-exposure by just one stop will produce incorrect results, although computer scanning can help rectify these errors to some extent. Print film, however, will produce excellent prints even if the negative has been underexposed by one stop or over-exposed by up to two stops: an extremely useful feature.
The final consideration when choosing a film, whether slide or print, is its ‘speed’. This is an indication of how quickly it reacts to light and is measured in ASA (or ISO). The standard film speed is 100 ASA, which gives good results in most conditions. The lower the ASA number, the slower it will react to light. Using a fast film will allow you to use a smaller aperture for increased depth of field, or a faster shutter speed for freezing quick-moving subjects.
But there’s no such thing as a free lunch, and fast films produce more grainy, less sharp-looking images, with less contrast and colour saturation. In comparison, the slower films (less than 100 ASA) offer almost perfect, grain-free sharpness, with maximum contrast and colour. Fuji Velvia is a typical example and is used by a lot of close-up photographers.
Just as computers have blurred film choice, so, too, have a new generation of slide films, which have been designed specifically for ‘pushing’. This means they can be exposed at any speed between 100 and 1000 ASA (the whole roll), without the image quality being adversely affected, as long as the film is then processed properly: you need to make sure that whoever’s developing your film knows the speed at which you exposed it. A good example of this type of film is Fujichrome MS100/1000.
Print films can also be pushed, but the grain increases much more than with slides, and few companies offer the processing facility.