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Chapter 6


Film


Film, or your recording medium, is the heart of all photography. It is also much misunderstood. People go to great lengths in the purchase of a camera, photo equipment, travel expense, etceteras. And then look for a bargain at the film and processing counter.

Regard film as cheap. Its cost is nothing compared to the heartache of lost photos.


Color Slide Film

This film is identified by the term, chrome. Agfachrome, Kodachrome, or Fujichrome are color slide film. When slides are held up to the light the colors appear as they really are, that is, red is red, blue is blue. That's why they are called color positives as opposed to negatives.


Color Print Film

This film is used to make reflection prints, what we loosely call pictures. It is identified by the term color, such as, Agfacolor, Kodacolor, and Fujicolor.

This film will produce color negatives from which color prints are produced. The negatives are opposite (on a color wheel) the true color that appears in the prints. To see this for yourself just compare a print with its negative.

The films you are probably familiar with are balanced for daylight. That is, they will give you proper color rendition when exposed to the light of the sun, or electronic flash.

Electronic flash units are designed to create light that has the same characteristics as daylight. This is no accident. So, daylight film works fine when exposed to electronic flash. This is not true for all films.


Films Designed For Light Other than Daylight

        Click for information on Color Temperature.

Some films are designed to give proper color rendition when exposed to the light from an electric incandescent bulb with a color temperature of 34200oK (K refers to temperature in degrees Kelvin). This, 3400oK, film is Type A film.

The 3200oK film is referred to as Tungsten Film . This means that the film is designed to be exposed to the light from a bulb with a tungsten filament operating at 3200oK.

The incandescent lights in your house, while they do have a tungsten filament, do not operate at this temperature. Actually the lights in the average house are not a good source for photographic purposes when using film. With digital photography they work out fine because as digital camera's have a feature called automatic white balance. This allows the digital camera to correct the light so that the picture appears as if it were photographed with daylight.

Note: If you are using tungsten bulbs and are having problems getting the correct color in your photographs, check the operating voltage of your electricity. Should the voltage fall significantly below 120 volts it will cause the bulbs to operate at a lower temperature than they are designed to, and will effect their color output.


Black and White Film

This film has no clear cut, across the industry designation as color films do. If unsure ask for black and white and let the photo person help you decide which is best for your needs.

These films do form two distinctly different kinds though: conventional black and white film and chromogenic film.

Conventional Black and White Film

This is the film that has existed for as long as photography itself. It was the first film developed and predated color films.

Most of these films are designed to produce a negative. There are black and white slide films, but they are specialty films. If you need this product be sure to arrange for special processing because your local lab probably won't be able to handle it. You will need a professional camera shop or a professional lab. Be sure to ask for a contact sheet. A contact sheet is one piece of photographic paper with an entire roll of film printed on it.

From this you can choose which negatives you want enlarged and how they are to be cropped without going through the expense of printing a lot of pictures that you may not want or need.

Chromogenic Black and White Film

This is black and white film that is developed in color chemistry. This your local lab can do for you.

With conventional black and white film there are many ways to process it. With chromogenic film your processing decisions are made for you. You use color chemistry and that's that.

This film has some advantages over conventional film. It is more forgiving of exposure errors and has finer grain in the shadow areas when overexposed.

Prints from chromogenic film will be on color paper, don't forget, if your prints have a color cast to them it means the photo folks did not take the time to make you color neutral prints. This they can do with some adjustment of the their equipment.

These prints can be made to have tones similar to a sepia toned print. This is the warm coloration you sometimes see in old photographs. The same is true for other slight color castes that you may want as a part of the photograph's overall character.

However, if these color casts are something you do not want and the photo finisher tells you that they cannot color neutral your prints, well, they just don't want to take the time.

For a truly white, colorless process for your black and white pictures. Ask for your prints to be made on Kodak Ektamax paper. With the same chemicals that the lab uses for color paper processing the Ektamax process is absolutely colorless.

You may need to ask around for this service and don't expect to see your results in an hour.

You can also have existing black and white negatives that were processed conventionally made on Ektamax paper.


Film Processing

Taking the picture is only the first step. The quality of the processing will influence your results to a great degree.

Here are some things to be aware of:

  • Do not use a processing lab you have not used before to develop pictures that are important to you or that cannot be taken again.

  • Verify the film to be used, its purchase price, availability, processing cost, and the cost of enlargements. Do this before you take the pictures. Preplanning will avoid aggravation and heart ache later.

  • For truly priceless moments use several rolls of film. Don't send them all for processing at the same time, better yet, use more than one lab.



ISO

International Standards Organization. ISO, in the photographic sense, refers to a film's sensitivity to light, the higher the number the more sensitive the film.

When the ISO number doubles the sensitivity of the film doubles. ISO 400 is twice as sensitive as ISO 200. Or you could say that ISO 400 film will take the same picture that ISO 200 will, but it requires half the exposure because it (the 400 film) is twice as sensitive.

Film speed

Films are loosely called slow, medium, and fast. This is loosely known as film speed.

Slow films are those below ISO 64.

Medium speed films are ISO 64 to ISO 200.

Fast films have an ISO number of 200 or more. Fast film is used in low light or where you need to shoot at high shutter speed. Generally, Medium and low speed film will give you better results, but will not always get the job done.

And please keep in mind that what is considered slow, medium and fast will change as film continues to improve.

It is the concept of slow, medium, and fast that is important not the specific numbers. Things change. Once written this document stays the same. Just because this can't change does not mean that you should always take it literally, in fact, you should not take everything in here literally. You, too, must allow for change.


DX Coding

This allows the camera to determine the films ISO and automatically set the camera's exposure system to that ISO setting. Of course, the camera and the film canister must be designed to do this.

To check this on your camera open your camera's back and look in the area that holds the film canister. If you find little prong type things, actually electrical contacts, the camera is designed for DX coded film containers.

DX coded film canisters have a black and rather square looking paint job along the side of the film can that mates with the electrical contacts. In this way is the film can able to communicate with the camera.


Color Temperature

Color temperature refers to "type" of light that a film is designed to be exposed to. Here, type, is used to mean how the light is produced. Whether from the sun, a light bulb, an electronic flash, a fluorescent light, or a candle.

Each of these sources have their own color temperature.

This is only important when using color film.

You have seen the way people look red or orange when photographed indoors under house lighting with daylight balanced film. The happens because house lights are richer in the red end of the color spectrum than daylight. So, when daylight balanced film is used under this redder light, skin tones appear reddish. Under fluorescent lights people will be a nice shade of green. This is referred to as color shift.

Color temperature is measures in degrees Kelvin (oK), after Lord Kelvin.

Daylight film is balanced for about fifty-five hundred degrees Kelvin (5500oK).

To be absolutely certain of exact color reproduction color correction (CC) filters and a color temperature meter must be used. As you might expect this equipment can get expensive, but, keep this in mind if you ever need to reproduce exact color.

It is interesting to note that those colors with lower color temperature are termed as warmer (that is redder), while those with higher temperature (light that is bluer) are called cooler. Actually the opposite is the case. Why? Red we perceive as a warm color and blue as a cool color.


Color Temperature of Various Light Sources
Light Source Color Temperature
American daylight6,500 oK
American daylight, overcast 7,500 oK
Candlelight1,900 oK
Clear blue sky9,000 oK
Electronic Flash, (varies from one model to another )6,500 oK
Fluorescent daylight tubes4,800 oK
Fluorescent warm-white tubes3,700 oK
Household incandescent lamps2,700
Mean noon sun5,000 oK
North sky, blue10,000-20,000 oK
Photoflood lights3,400 oK
Projector lamps3,100 oK
Studio floodlights3,200 oK



Light varies widely in its color content.

  • Sunlight, 5500oK is about one-third red, one-third green, and one-third blue.


  • Studio floodlighting, 3200oK is about 49% red, 34% green, and 17% blue.


  • Candle light, 1900oK is about 75% red, 17% green, and 8% blue.


    Here Some Film Related Terms

    Here are a few terms you will need to know and will certainly hear spoken by pros and advanced amateurs.


  • Preflash. When a very limited exposure is used before the main exposure to record the image. This technique is used on film and paper to reduce contrast and/or grain.


  • Pull Film. This refers to exposing film at an ISO which is lower than what the film is rated for. The processing must compensate for this.


  • Push Film. this refers to exposing film at an ISO which is greater than what the film is rated for. The processing must compensate for this.


  • Reciprocity Failure. A loss of film speed occurs when film is exposed for very short (one ten thousandth second or less) or very long exposures (hours). This is not usually a problem under normal circumstances. This can be a problem in astronomical photography where very long exposures are routine. See Time Exposure.



    Go take color pictures.


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