35mm
The most popular film size; 35mm wide with punched sprocket holes and made for both still and motion picture cameras. In 1913, Oscar Barnack, of 'Leitz ' first used it in a still camera when he created the 'Leica' prototype using movie film stock. The format is 24x36mm, unchanged from Barnack's prototype. In relation to other formats, 35mm gives the best compromise between image quality and versatility.

Ambient Light
The natural light in a scene.

Aperture
The opening in the front of the camera lens through which light passes to expose the film. Aperture size is usually calibrated in f-numbers, the larger the number, the smaller the lens opening, therefore the slower the shutter must be.

APS (Advanced Photo System)
APS was devised by a group of five manufactures: Canon, Fuji, Kodak, Minolta and Nikon as a 'breakthrough in camera and film technology' and created a new generation of 'point-and-shoot' cameras. Now, with hindsight, regarded as an interim consumer product which just filled a gap until the more innovative compact digital cameras became affordable. The film size is smaller than 35mm.

Autofocus
When applied to a lens, it is the ability of a lens to focus automatically on an object within its focusing sensors. This system, considered superior to others, is able to achieve very precise focus in the majority of situations, but is dependent on the light sensitivity of the sensor. Active autofocus systems have, by their very nature, limited range.

Available Light
Existing light surrounding a subject; whether natural or artificial, but not added by the photographer, like with strobes or speedlights.

Bit
The smallest unit of memory; a contraction from 'binary' and 'digit'. Binary digits are 0 and 1, also known as ONs and OFFs.

BMP
BMP is the standard Windows image format on DOS and Windows-compatible computers. The BMP format supports RGB, indexed-colour, grayscale, and Bitmap colour modes.

Burning
Selectively darkening a print or an area of a print. This is accomplished after the basic exposure, by extending the exposure time (or opening the aperture) to allow extra light to darken areas of the print while holding back the light from the rest of the image (with hands or card etc.); also called printing-in. This can be done with traditional printing or with an image editing program.

C41
The number given to a Chemical process for developing color negative film. (created by Kodak but adopted universally by every other manufacturer).

Clip test
A test to determine accurate development times using a small part of the exposed film as a sample.

CMYK
A color system based on the four colors used in color printing: Cyan, Magenta, Yellow and BlacK. Can also be a color mode used to define colors in a digital image. All Digital cameras & scanners are RGB devices, a color method based on combinations of the primary colors Red, Green & Blue this is the same as your TV and PC monitor. CMYK is primarily used when preparing digital images that will be printed using the process colors by a printer or publisher on a four color printing press.

Color correction
Filters which help balance the color rendition of a scene to match the color response of the eye.

Compact Flash
A common type of digital camera memory card, about the size of a matchbook. There are two types of cards, Type I and Type II. They vary only in their thickness, with Type I being slightly thinner. A CompactFlash memory card can contain either flash memory or a miniature hard drive. The flash memory type is more common.

Contact print
A print made from placing the negative in 'contact' with a sheet of photo paper and then exposed to light; the resulting "Contact print" is the same size as the negative and therefore not enlarged.

Contrast
A subjective judgment of the difference in brightness and density between shadow and highlight areas in an image. Contrast is affected by lighting, lens flare, film type, degree of development, enlarger type and quality of printing.

Cross process
To develop a film in the wrong process (e.g.: neg.(C41) film in trannie(E6) chemicals) to obtain a sometimes bizarre color or contrast effect.

Depth of field
The distance between the nearest and farthest objects that appear in acceptably sharp focus in a photograph. Depth of field depends on the lens aperture, the focal length of the lens, and the distance from the subject.

Depth of focus
Very narrow zone on the image side of the lens within which slight variations in the position of the film will make no appreciable difference to the focusing of the image.

Developer
A Chemical bath which converts exposed silver halides to black metallic silver, so making the latent image on exposed films or photographic papers visible.

Dodging
'Local' control of density in photographic printing achieved by shading (using your hands, small pieces of card or various other dodging tools), therefore, holding back the image-forming light from a part of the photo to make that area of the print lighter.

DPI (Dots Per Inch)
A measurement of the resolution of a digital photo or digital device, including digital cameras and printers. The higher the number, the greater the resolution.

Dupe
A duplicate of an original. Usually the term is used to describe a duplicate transperancy.

DX code
An electrical system built into recent 35mm cameras to automatically adjust the camera for the correct film speed.

E6
The number given to a Chemical process for developing colour transparency film. (created by Kodak but adopted universally by every other manufacturer).

Emulsion
The light-sensitive material (which is suspended in micro-thin layers of gelatin) that is coated onto different bases to make photographic film, or paper.

Exposure
The quantity of light allowed to act on a photographic material; the lens aperture controls intensity or amount of light, and the shutter speed (or the enlarger timer in printing) controls the time.

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