Glossary

Photographic terms used in this book, and what we mean when we use them

accuracy

is a measure of closeness to an accepted target value and indicates the proximity to that value. The closer a measurement is to the target value, the more accurate it is considered to be. A measurement can be accurate but not precise. (see precision)

analog photography

is a chemically based imaging process in which light is directed onto a light-sensitive emulsion to create a latent image, which is subjected to subsequent processing steps, making it visible and insensitive to light. This was the dominant form of photography for much of its history, but is now supplemented by digital photography. (see digital photography)

art

is the conscious expression or application of creative human skill and imagination, producing aesthetic work, primarily appreciated for its beauty or emotional power by a group of people. (see fine art)

brightness

is a subjective sensation to luminance and cannot be measured, but it can be approximated by psychological scaling procedures. (see luminance)

density

is a logarithmic measure of light transmission and reflection in negatives and prints. As a convention for this book, we have used ‘relative’ transmission and ‘absolute’ reflection densities, unless otherwise stated.

digital imaging

describes the digital workflow, including digital image capture, manipulation, compression, storage, printing and display. (see digital photography)

digital photography

is one of several forms of digital imaging in which light is directed onto a light-sensitive image sensor and recorded as a digital file for further processing. This book considers it as a supplement to analog photography. (see digital imaging and analog photography)

emulsion

in silver-gelatin photography, the emulsion is a light-sensitive layer of silver-halide crystals, suspended in gelatin and coated onto a substrate of glass, plastic film, resin-coated or fiber-base paper. (see film)

film

is a thin flexible strip or sheet of plastic, coated on one side with a light-sensitive emulsion for exposure in a camera and subsequent development into one or several negatives. (see negative)

fine art

is crafted with the highest level of skill and experience and is primarily appreciated for its creative, imaginative and aesthetic value. (see art)

gradation

refers to the change of image tones in images, negatives and prints. (see tonality)

illumination

is the light falling onto a surface, and its intensity can be objectively measured as illuminance (lux or lm/m²) with an ‘incident’ lightmeter. (see lumination)

image

is a visual representation of an object, scene or person. An image can be seen on a ground-glass, captured on film, viewed in a negative, projected onto a surface, or it can be produced on photographic paper to create a specific print, but it can never be touched, because it is a ‘only’ a visual sensation. (see paper and print)

lumination

is the light emitted or reflected from a surface, and its intensity can be objectively measured as luminance (nits or cd/m²) by a ‘reflected’ lightmeter. (see brightness and illumination)

monochrome

refers to any B&W or single-color image or print, including toned silver-gelatin and alternative-process prints, such as albumen, carbon, gum, oil, platinum, palladium or Cyanotype printing.

negative

is an exposed and developed photographic image, recorded on film or coated glass, showing light and shadow values reversed from the original scene to produce print positives. The negative is an intermediate product of the traditional, analog photographic process. (see film)

paper

is a term used throughout the book as an abbreviation for ‘photographic paper’. It describes a material and is not directly related to a particular image or print. For example, the term ‘paper contrast’ is used to describe an image-independent material characteristic. (see image and print)

photography

is an imaging process through ‘painting’ with light. Light, reflected or emitted from objects, is captured by the photographic lens of a camera, where the resulting information is recorded by a light-sensitive medium. (see analog and digital photography)

pictorial range

is a term used in the Zone System to describe a seven-zone tonal range, including all image tones of pictorial value, from the beginning of Zone II to the end of Zone VIII. (see textural range)

pixel

is the smallest item of information (picture element) in a digital image, containing luminance and color.

precision

is a measure of reproducibility or repeatability independent of the closeness to an accepted target value. The closer a number of measurements are to each other, the more precise they are considered to be. A measurement can be precise without being accurate. (see accuracy)

The purpose of this small glossary is to define our understanding and usage of a few photographic terms, as they appear throughout the book. We also want to make sure that some common terms are not confused with each other. This is not a claim for the actual or ‘true’ meaning of these terms, nor do we wish to challenge someone else’s understanding of them. We merely offer an explanation of what we meant when we used them.

print

is a term used throughout the book as an abbreviation to identify a unique photographic print. It describes the final object of the photographic process, which you can see and hold in your hand, and it is directly related to a particular image. For example, the term ‘print exposure’ can be used to describe an image-dependent requirement. (see image and paper)

quality

describes the state of performing as intended, within identified specifications, while fulfilling customer expectations. A high-quality image, for example, renders a scene as expected with brilliant highlights, clear separation and good contrast throughout the midtones, and open, but dark, shadows. A high-quality print, on the other hand, does not fade or change tonality during its expected life span.

subject brightness range

is a term is used throughout the book to describe a range of measurable light intensities. Strictly speaking, this is not correct, because brightness only refers to the human perception of luminance and not the measurable quantity of it. The term ‘subject luminance range’ is technically more accurate, but it is not frequently used in photographic literature. To avoid confusion, the incorrect, but more generally understood, term and its abbreviation, SBR, is used instead.

textural range

is a term used in the Zone System to describe a six-zone tonal range, including all image tones having definite qualities of texture and the recognition of substance, from the center of Zone II to the center of Zone VIII. (see pictorial range)

tonality

refers to the range of image tones in images, negatives and prints. (see gradation)