Film Basics for Digital Photographers

This chapter is from the book

Absolute Beginner's Guide to Digital Photography

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This chapter is from the book

This chapter is from the book 

Absolute Beginner's Guide to Digital Photography

Learn More Buy

Selecting and Using Film

If you already own a 35mm film camera or a medium-format camera and aren't ready to invest in digital, you might want to stick with film. You can always purchase a decent flatbed scanner with a negative insert for less than $300 and scan your negatives. Fortunately, your choices for film are extensive, even after five years of creeping digital.

This section discusses black and white and color. Thanks to Photoshop and scanners, converting color to black and white has become child's play. However, black and white still has a place in the photographer's portfolio because of its latitude, contrast, saturation, and artistic element (see Figure 3.1). Most of the information on these two pages applies to both black and white and color.

Figure 3.1 Black and white still plays a major role in today's color, digital world.

©2004 Amanda J. Smith

Color Balance and Film

Daylight-balanced color films produce the most natural colors in the relatively bluish light of daylight or electronic flash. Tungsten-balanced color films give the best results in the relatively reddish light from incandescent light bulbs. Digital cameras must deal with lighting colors as well, but often their automatic white balance feature overcomes any color cast.

Thirty-five millimeter cameras use 35mm film, which is packaged in cassettes of 12, 24, or 36 exposures per roll. Some 35mm films can be purchased in 50- or 100-foot rolls, then bulk loaded into separately purchased cassettes. This reduces the cost per exposure and, if you use a great deal of film, can be worthwhile.

Medium-format cameras use roll film. Roll film is wound around a spool and is backed with a separate strip of opaque paper to protect the film from light. Depending on the camera, 120 roll film makes 16 6x4.5cm, 12 6x6cm, 10 6x7cm, or 8 6x8cm images. Each size applies to different cameras. Fuji makes a popular studio camera that takes 6x8cm images. Mamiya is the leader in 6x7cm cameras, Hasselblad leads with 6x6 cm cameras, and Pentax and Bronica make excellent 6x4.5cm cameras.

Most of these cameras accept another type of roll film called 220, which has paper only on the end; this reduces the thickness of the roll so that more film can be wound on the spool and more exposures made.

Sheet films, or cut films, are designed for large-format cameras, such as 4x5-inch and 8x10-inch cameras (also called view cameras). Sheet film is packaged 10 or more sheets to a box. Some film must be loaded in film holders before use, although you now can buy sheet film in disposable holders.

Do You Need a Film for a Special Purpose?

Aside from Polaroid film, which contains developing chemicals in each picture, a number of unusual film technologies exist.

• High-contrast films produce only two tones: the clear film base and black, without intermediate tones of gray.

• Infrared films respond to infrared wavelengths that the human eye cannot see. These are available in black and white and color.

• Chromogenic black-and-white films, such as Ilford XP2, produce a dye image rather than a silver one. They have excellent exposure latitude, which means you can expose individual frames at different film speeds. Frames exposed at about ISO 100 will have finer grain, but frames on the same roll of film can be exposed at speeds as high as ISO 800 and still produce printable negatives. This differs from conventional films, which require you to expose the whole roll at a single film speed. Chromogenic film must be developed as if it were a color negative (in Kodak's C-41 chemistry or Ilford's version of the same process), which is available at your corner drugstore.

Storing Film Properly

Store film away from heat. Heat affects any film badly, so don't leave it where temperatures might be high, such as in the glove compartment of a car on a hot day or near a heater in winter.

For long-term storage, refrigerate film. Refrigeration extends the life of film. Room temperature is fine for short-term storage, but for longer storage, especially in warm weather, a refrigerator or freezer is better for most films. Make sure that the dealer has refrigerated film if that is what the manufacturer recommends.

Protect film from moisture. The original film packaging should be moisture-proof, but if you refrigerate the film after opening the box, put the film in a moisture-proof container like a tightly closed plastic bag.

Let refrigerated film warm to room temperature before using it to prevent moisture from condensing on the film surface. One roll of film (or a 10-sheet box of sheet film) needs about an hour to warm up; a 100-foot roll of bulk-loaded 35mm film or a 100-sheet box of sheet film needs about four hours to warm up.

Film Speed

The faster the film speed, the less light required to produce an image. Therefore, faster film can be used in dimmer light, with faster shutter speeds, or with smaller apertures. A fast film is useful indoors, for example, especially if you use only the existing light in the room and do not supplement it with electronic flash or photofloods. A slower film is good for brightly lit scenes, such as outdoors in bright sun. The faster the film, the higher its film speed number.

What film speed should you use? Faster films tend to produce grainier pictures, so theoretically you will get the best results by selecting the slowest film usable in each situation. In practice, however, it is inconvenient and unnecessary to work with several film speeds. Some photographers use a relatively fast ISO 400 film for almost all their work. One type of film might not be enough, but a fast ISO-rated film and a slower, finer-grain film are enough for most situations (see Figure 3.2).

Figure 3.2 ISO 100-, ISO 400-, and ISO 1600-speed film compared.

Film Speed Rating Systems

A film speed number indicates how sensitive that film is to light. There are several rating systems for film speed. The most common in English-speaking countries are ISO (International Organization for Standardization) and EI (exposure index). ASA (American Standards Association) is an older rating system. All use the same numerical progression: The film speed rating doubles each time the light sensitivity of the film doubles.

The higher the number in a given system, the faster the film—and the less light you need for a correct exposure (see Table 3.1). An ISO or EI or ASA 200 film is twice as fast as an ISO 100 film (one stop faster), half as fast as an ISO 400 film (one stop slower). For a correct exposure, the ISO 200 film needs half as much light as (one stop less than) the ISO 100 film, twice as much light as (one stop more than) the ISO 400 film.

Table 3.1 Film Speed and Shutter Speed

Film speed influences heavily how the film is used. Sports photographers that still shoot with film must use high-speed film because higher shutter speeds capture motion with no blur. Slower film speeds are used for portrait photography because maximum clarity is desirable (see Table 3.2).

Table 3.2 Some Typical Film Speeds and Their Uses

Film Speed and Grain

The faster the film, the more visible its grain (see Figure 3.3). The light-sensitive part of film consists of many tiny particles of silver halide spread throughout the film's emulsion. A fast film is fast because it has larger crystals than a slower film. The larger crystals more easily capture the few rays of light in a dark environment. When the fast film is developed, its larger crystals yield larger bits of silver. The advantage is that the film needs less light to form an image. The potential disadvantage is that these larger crystals in very fast films reproduce what should be uniform gray areas—not as smooth tones—but with distinctly visible specks or grain.

In general, each increase in speed also increases graininess. If maximum sharpness and minimum graininess are your desire, select slower rather than faster films.

Some newer films have reduced graininess. Recent advances in technology have changed what used to be a fairly direct relationship between film speed and grain. The silver halide crystals in T-grain or core-shell emulsions, such as in Kodak's Max or Ilford Delta films, have a flattened surface that exposes more of each crystal to light. The result is film with significantly reduced grain for its speed.

Figure 3.3 The photo on the left was taken with film camera using ISO 800 speed film. The photo on the right was taken in low light with a digital camera at ISO 400.

Other factors also affect grain. Graininess is more obvious in areas of uniform tone—such as the sky—than it is in textured areas. Also, graininess becomes more apparent the more a picture is enlarged. That is why a print from a 35mm negative usually looks grainier than the same size print from a larger negative. Grain is also affected by factors such as the film developer, the printing paper, and the type of enlarger used. Graininess also increases when the negative is overdeveloped or overexposed.

Fast-Speed Film: When Speed Is Essential

A fast film (ISO 400 or higher) is useful for stopping motion (see Figure 3.4). Because it requires less light than a slower film, you can use a faster shutter speed, which will record a moving subject more sharply than a slow shutter speed.

Figure 3.4 Action and sports photography is the last film stronghold. Digital cameras are only now fast enough for sports photography.

Fast film is an asset in dim light. Because fast film needs less light to produce a printable image, it makes photography easier indoors, at night, or in other low-light situations (see Figure 3.5). If you increase the development (ask your lab), you can push the film, which lets you expose at a film speed even higher than the one that is designated by the manufacturer.

How fast is fast? The film speed of Kodak's T-Max P3200 film, for example, starts at 800. Its speed can be pushed to 3200, and with a sacrifice of image quality, up to 25,000. A fast film might show increased grain and loss of image detail, especially if you push the film. But the advantages of fast film can outweigh its disadvantages when you need the speed.

Medium-Speed Film: The Best General Purpose Film

A medium-speed film around ISO 100 delivers better sharpness and detail than faster films (see Figure 3.6). It is useful when you want to show fine detail or want to enlarge a negative considerably with a minimum of grain. The film has smaller silver halide crystals and a thinner emulsion compared to fast films, which increases its capability to render detail sharply.

Figure 3.5 Low-light photo taken with ISO 1600-speed film.

Figure 3.6 Film with an ISO rating of 100–400 is usually fast enough for most outdoor photography.

If light is moderately bright, a film of medium speed still lets you use a relatively fast shutter speed, so you can hand-hold the camera or record moving objects sharply. The slowest film speeds would require a tripod to hold the camera steady during a longer exposure of the same scene. Medium-speed films are also useful if you want to maximize the depth of field by using a small aperture, which is not always feasible with a very slow film.

Slow-Speed Film: Maximum Detail

Slow-speed films of ISO 50 or less are mostly color. The reason is that grain has been reduced so much in black-and-white films that few are still available at speeds under ISO 100.

A slow-speed color film produces brighter colors and a crisper image than faster color films. The original Kodachrome film was rated at ISO 25; Fuji's hugely successful Velvia film is rated at ISO 50.

One exception to color-dominating, slow-speed films is the black-and-white recording film called Technical Pan 2415. Normally this ISO 25-rated film is used for recording text and other high-contrast applications. Develop this film with a special Technidol developer, however, and normal photographs are possible. The extremely fine grain and high resolution of this film enable you to blow up 35mm negatives to 20x30 inches with no apparent grain.