agitate: Constant rocking motion of materials in liquids to ensure even coverage.
analogue/analog: Has come to mean anything that is not digital. Traditional photography that uses film or emulsion.
analog: The visuals we are used to in a nondigital environment, which actually comes from a stream of continuously variable data in the form of light energy, with variation being represented by varying quantities of luminosity. An analog image is made up of some sort of marks on film or paper that collectively create the picture you see.1
aperture: The opening in a lens that adjusts and controls the amount of light allowed to pass through to the lens. Usually described as an f/stop or f/number.
archival: Having a quality of maximum permanence.
banding: Interruption of graduated shades caused by the loss of tonal data. Appears as a distinct line between two tones.
Becquerrel: A form of Daguerreotype.
binary: A computer machine language that depicts letters, numbers, and symbols as sequences of the two digits 0 and 1, or as sequences of “off” and “on.” The numbers symbols are indicators, not actual numbers that turn on or off little switches. This 0-1 unit is called a bit, which is a reduction from the phrase BInary digIT. Digit gives us the term digital, and 8 bits = 1 byte, from which terms like megabyte and kilobyte come.
bit: See binary.
blow up: To make an enlargement.
bracketing: Purposely shooting a camera exposure correctly, then overexposing one shot and underexposing another shot.
burning or burning in: Giving more light than the normal exposure to a selected area of the emulsion or digital image by adding more exposure to that particular area. Burning usually makes that area darker; the technique often is used to retain more detail in the highlights.
camera lucida: An optical aid for drawing, often portable, that consists of a prism that focuses rays of light from a scene onto a sheet of paper that can be seen and “traced.”
camera obscura: Latin for “dark room” and used by some Renaissance painters. An outside scene would be projected through a small hole in the wall of a room onto the opposite (white) wall and would appear inverted. Evolved into a smaller, portable, darkened boxes that used a lens, mirror, and/or ground glass to aid in drawing and, eventually, in early photography.
capture: Act of taking and saving a picture digitally.
clipping: Highlight and shadow values that have gone completely black or completely white, losing detail in a digital image.
color management: A control for getting consistent and accurate matches from your input device (scanner, camera, telephone) to your computer monitor to your output device (usually, a printer).
color separation: The process of dividing full-color originals into the primary process printing colors: magenta, yellow, and cyan.
contact frame: See printing frame.
contact print: A photographic image made from a negative or positive placed on the surface of sensitized paper, film, or printing plate, and exposed to light.
continuous-tone: An image containing gradient values as well as black and white.
contrast: Differences in tones in a picture.
copy: (1) Any furnished material or artwork to be used in printing; (2) in typography, written rather than visual image; (3) in electrographics or copier art, an interpretive print or reproduction.
correct reading: Facing the same direction as the original.
cursor: A moving indicator on a digital device’s screen that shows the position where a user can make a selection or enter type. See mouse.
curves: Graphs in digital image software showing how input is related to output.
Daguerreoytpe: First successful photographic process introduced publicly (1839). The image was exposed directly through a camera onto a polished silver plate.
darkroom: A light-tight area, either completely dark or specially illuminated, for handling light-sensitive materials.
dense negative: A reversed-tone transparency so dark that it transmits very little light.
density: Measure of opacity of an image. The emulsion buildup in a negative or positive. The greater the exposure to light and the longer the developing time, the more solid the density.
developer: A solution rendering latent images visible after exposure in analogue photography.
digital: Electronic data representing information as numbers, based on discrete binary digits, for processing by a computer. See also binary.
digital imaging: Using computer devices and processes for producing pictures.
dimensional stability: The quality in a support of not changing its size by shrinking or stretching.
dodging: Holding back some light on an area of the digital image or the analogue emulsion during an exposure. Dodging usually renders that area lighter and often is used to retain more detail in the shadows.
duplicating film: Film that does not reverse the image but repeats it negative-to-negative or positive-to-positive. See film.
easel: The device, usually a metal frame, for holding light-sensitive materials flat under the enlarger during an exposure.
electrographics: The use of copy machines, such as Xerox™, to generate art.
emulsion: A light-sensitive coating on film or paper.
enlarger: Equipment for projecting small transparencies to larger formats in a darkroom.
exposure: Subjection of a photo-sensitive coating or digital image to the action of light.
exposure unit: The source or system used to shine the appropriate ultraviolet light onto photosensitive emulsion.
eyeballing: Judging registration or exposure of images by visual inspection.
ferric: Substance that contains iron.
file format: Basic structural database with instructions on how to encode, save, and extract electronic information in a file. May include, for example, RAW, JPEG, TIFF, and EPS.
film: A light-sensitive material on a clear base.
fixer: A solution that removes unexposed silver halides (light-sensitive metallic compounds) from the emulsion and makes the analogue image stable and impervious to white light. The amount of time the emulsion spends in the fixer is called the clearing time. Fixer is also known as hypo.
flat: The sheet of stripped-in negatives used to expose a photo-sensitive surface underneath. Also, a term used to describe an image without much contrast.
flatbed scanner: Optical tabletop device in which flat analog art is held level on a glass platen much like an office copier while a sensor passes over or under it and converts it into digital information. The image then can be manipulated on a computer, shows little, if any, depth, and can be purchased with an attachment for scanning transparencies.
fog: Density in the negative or print caused by errant light or chemical action not related to the normal formation of the analogue image. See safelight.
f/stop or f/number: Fixed sizes or settings for lens apertures.
gelatin: A binder made from animal parts used as a support for the light-sensitive particles in certain emulsions, as sizing that fills in pores on the surface of paper, or as a method for printmaking instead of using a plate to accept ink.
generation: Each succeeding stage in reproduction from the original.
grain: (1) The direction in which most fibers lie in paper; (2) silver particles on film and paper, not usually visible unless viewed under magnification.
graphic arts film: A variety of orthochromatic films.
gray scale: A strip of standard gray tones ranging from black to white, used to measure tonal range and contrast. Also called a steptable.
hardware: All the components of a computer system except the programmed instructions (software).
heliography: An obsolete term for printing processes that depend on the sun (or ultraviolet light).
high contrast: An image or process that yields only black and white, or shadow and highlight.
highlight or high key: The brightest light accents in the subject. Therefore, the lightest of whitest parts in the positive and the darkest areas of a film negative.
histogram: Digital graph showing how a complete array of values in an image are distributed. The height of the graph represents the number of pixels, or picture elements, in the image at any particular value.
hypo: An abbreviation of the obsolete term for the chemical sodium thiosulfate (hyposulfite of soda) used to fix the image on some photo emulsions after development. The term also refers to the baths compounded with it. See fixer.
inkjet: A type of printer that interprets digital information and recreates an image or text by spraying electrostatic droplets of ink onto a substrate.
input: All methods of obtaining information into a computer, such as a scanner, smart phone, or digital camera.
intensification: In photography, to increase the density of a negative or color in a print.
interpolation: See resampling.
ISO: A number assigned by the International Standards Organization, which indicates film speed or its equivalent camera sensitivity to light. Used to be known as ASA for the American Standards Association.
laser printer: An apparatus used to transfer type and graphics from a computer or copy laid on a glass platen onto a substrate (“hard copy”). Very strong light waves first draw the image, in the form of high-resolution dot patterns, onto a metal drum in the printer, which then electrostatically attracts dry ink powder (toner) to itself, in much the same manner as an office copier.
latent image: The invisible analogue representation in the emulsion after exposure, later made visible by development.
layout: Drawing or sketch of proposed printed piece.
levels: One of the Adobe Photopshop® correction tools to modify the distribution of tones in an image.
light table: Equipment used for viewing and preparing transparencies, consisting of a translucent glass or plastic top with lights behind that shine through to illuminate the surface.
line: Processes and images that comprise black and white without intermediate gray tones.
line shot: High-contrast reproduction of original material.
lith or litho film: Also known as ortho film because it is not sensitive to red light waves and is commonly employed in photolithography.
loupe: Magnifier for checking image details.
low key: Shadow or dark values.
mask: Opaque material used to cover selected image areas during the exposure.
mercerized: Treatment under tension with caustic soda to give cotton cloth more strength and receptiveness to dyes.
middle tones or midtones: Shades between highlights and shadows.
mouse: A physical device used to move the cursor on a computer screen. Usually, buttons on either side of the mouse (left click and right click) can control certain digital operations, while the wheel in the center can move the screen up or down. See cursor.
negative: (1) An image in which the values of the original are reversed (usually on film); (2) a process in which the tones are reversed.
noise: Unwanted electronic information, showing up in a digital image as lighter pixels in an otherwise dark-toned area.
nonrepro blue: Special blue marker that does not show when photographed.
opaque: (1) A condition in which no light is allowed to pass through; (2) special markers or paints that block light; (3) to block out unwanted areas on transparencies before printing.
optics: Physical study of light and how it reacts with and to other materials.
orthochromatic: Analogue photo surfaces insensitive to orange and red light but sensitive to visible blue and green light.
panchromatic: Analogue photo surfaces sensitive to blue and green visible light and some of the red spectrum.
photogram: A photo image produced without using a negative or camera by allowing an object or stencil to cast its shadow directly onto the recording surface.
photorealism: Exceedingly “realistic” or representational style of drawing or painting, popular in the 1970s and 80s and based on photographs, rather than live observation, as the source.
photosensitive: The quality of reacting to light through chemical action.
Pictorialists: During the end of the nineteenth and beginning of the twentieth centuries, an international aesthetic movement of photographers who manipulated a scene to convey emotional, rather than “documentary,” content.
pigment: Particles used to give color, body, or opacity to a semiliquid artists’ material.
pixel: The smallest component of a picture that can be individually processed in an electronic imaging system. The smaller and closer together the pixels, the clearer the image. The term pixel is short for “picture (pix) element (el).” Pixels are often called dots, as in dots per inch (dpi).
pixellization: A digital effect produced by dividing an image into groups of coarse square tile shapes, which display the averaged value of the picture elements they contain. See pixel.
positive: Photo surface containing an image in which the dark and light values correspond to the original subject.
posterization: Separate black-and-white negatives, each of which records either the highlights, the middle tones, or the shadows of the same image. In printing, usually each negative is used with a different color.
press type, press tape, press graphics: Materials with adhesive backings that will stick to other surfaces when pressed down. They can be used in making transparencies. Also known as “pressure-sensitive graphics.”
printing frame or contact printing frame: A shallow unit, usually made of wooden edge, glass plate, and backing, for holding negatives in strict contact with the emulsion during an exposure. In practice, light shines through the top glass, through the negative, and onto the photo emulsion.
print washer or syphon washer: Equipment for the flow of clean water and the elimination of dirty water.
profile: International Color Consortium (ICC) profiles are descriptions of a specific output device used by image software to match colors from one input or output device to another.
rag paper: Made from the degeneration of linen and cotton, as opposed to wood pulp.
register: Fitting two or more images in exact alignment with each other, or repeating the same image on top of itself.
resampling: Also known as interpolation, or altering the image file to augment or reduce the number of pixels. When a file is permanently reduced in size, data are lost; if a file is increased in size, arbitrary data are added.
reversal: The basis of most analogue photography, which is the conversion of a negative to a positive (or a positive to a negative).
right reading: See correct reading.
rubylith: A red adhesive paper, acetate marker pen, or tape used to opaque or block out portions of an image during exposure. Different manufacturers have different names for the same kind of product.
safelight: A special darkroom lamp used for illumination that does not harm the sensitized materials. Image density resulting from too much exposure to a safelight is called fog.
saturated solution: A liquid and chemical mixture so concentrated that no more of the chemical can be dissolved in it.
scanner: A machine that captures visual information and transforms it into digital data.
shadow: The darkest parts of a positive; the clearest parts of a film negative. Low-key areas in a computer image.
sizing: Treatment of paper that gives it resistance to the penetration of liquids or vapors.
sliders: When using certain adjustment layers in Adobe Photoshop™, small triangles or buttons (in Lightroom™) that move along a path appear below the window. By moving these sliders, you can control changes to the image.
software: Programmed instructions that tell computer hardware equipment what textual, graphic, or other informational functions to perform.
stat camera, graphic arts camera, copy camera, or process camera: The instrument with which photographic transparencies can be made, consisting, at least, of a light-tight area for holding film, a lens to direct and focus the image, a place to put copy or original artwork, and a light source. Although there are differences between stat cameras and copy cameras, the terms are commonly used interchangeably. With the advent of home scanners and computers, these cameras are becoming rare.
stock solution: Main concentrate of liquid chemistry from which working mixtures are made.
stop bath: A solution that halts development of emulsion, usually acetic acid.
stripping: The positioning of negatives or positives on a flat prior to exposure.
support: The surface onto which an emulsion is coated.
test strip or test print: A photosensitized support exposed to light and developed in a systematic way, so that bands of different exposures indicate what the finished image might look like. A guide for determining the exposure of the final picture.
thin: A transparency of overall low density, or tending to be fairly clear.
thumbnail: A collection of stored digital images that may be displayed as a series of small representations, like viewing slides on a light table or a contact sheet in photography, rather than one by one in a projector.
transparency: An image that transmits light through part of it. A transparency can be in the negative or positive, handmade or photographic, large or small (a photographic slide).
ultraviolet light: Electromagnetic radiation having a wavelength shorter than the visible portion of violet in the spectrum but longer than X-rays. Sunlight is a common source of ultraviolet light.
vacuum frame: A glass and metal device employing an air pump for holding copy and reproduction material in place during exposure.
wetting agent: A liquid bath for film to help prevent dirt and water spots and to make the film attract less dust. It usually is the last bath the film touches in the development procedure.
white light: The visible spectrum of light, whether artificial or natural.
wrong reading: Facing the opposite direction from the original.
NOTE
1 Sesto, Carl. The Macintosh Designer’s Guide to Digital Imaging. New York: Wiley Computer Publishing, 1996.