معجم المصطلحات - ٣ - كتاب التصوير الضوئي

Glossary of Terms - 3 - Book of Photography

Film with superposed layers or (Tripak) A film composed of three layers of different emulsions, each layer sensitive to the basic color of the spectrum, and this principle related to the formation of colors in the emulsion is used in all current color photography emulsions.

Film type A A A reversible colored film designed for lighting at a temperature of 3400 Kelvin.

Film type B B A reversible colored film designed for lighting at a temperature of 3200 Kelvin.

Daylight model film Film tupe lumière du joure A reversible colored film designed to give natural colors when the subject is illuminated by a light source with a color temperature close to 5500 Kelvin.

Potassium ferricyanure Ferricyanure de Potassium is used in some bleaching solutions, Farmer's thinner, and some photo color changing solutions.

Phénidone is a reducing agent sometimes used instead of methyl (Genol).

The inverse square law of distance Loi de L'inverse du carre de la distance A basic law in lighting that states that the intensity of light from a point source decreases in inverse proportion to the square of the distance, the distance between the source and the illuminated surface, and thus when the distance is doubled, the received intensity (or surface illumination) decreases to 1/4 of what it was.

Resolving power The ability of the eye or photographic emulsion to transmit fine details, often measured in lines per millimeter.

Base or (basic) A chemical substance that has the ability to neutralize acids by giving them salts and water.

Alkalis Another name given to bases (see development accelerator).

Alkalinity Basicity The energy of a solution to act as a base.

Electric arc A light source resulting from the passage of an electric current between two electrodes.

Sensitivity measurement A scientific study of the laws of blackening of light-sensitive materials according to lighting.

Reflected light measurement Mesure de lumière reflechie A method of measuring exposure with the help of an exposure factor meter (an independent light meter or one attached to the camera and depends on measuring the light reflected from the subject (the degree of optical density), this method is the most common.

Incident light measurement Mesure de lumière incidente A method of measuring exposure with the help of an independent exposure factor meter (light measurement) and depends on measuring the light that illuminates the subject.

Density Densité The amount of silver formed in a photographic emulsion after processing, density
is equal to the logarithm of a corresponding dense shade.

Potassium carbonate Carbonate de Potassium is used in some formulations of developing solutions, as a development accelerator in the solution and releases an alkaline substance.

Sodium carbonate Carbonate de Sodium is a development accelerator used in many formulations of developing solutions and does the same thing as potassium carbonate.

Kelvin A unit of color temperature starting from absolute zero (2730) This unit
is used to indicate the color temperature of Light source, for example a tungsten lamp for photography = 3200 Kelvin.

Ammonium chloride is used for discoloration and bleaching.

Ferric chloride is used in some negative bleaching solutions. Gold chloride is used for discoloration of gold and is soluble in water.

Coma is an optical aberration that forms a circular or pear-shaped image bulging outward for bright spots
located outside the optical axis.

Lumen is a unit of measurement for the intensity of light.

Potassium citrate is used in many discoloration solutions. Magenta is a complementary color to primary green that can be obtained by mixing two light colors, red and blue.

Peroxide is used in the hyposulfite exclusion and accelerated washing method.

Retrofocus Optical mount applied to short focal length lenses that allows them to be used with single-object reflex cameras. The autofocus is larger than the focuser to allow the mirror to move.

Moving Bouge Blur image resulting from movement of the camera or subject while taking the shot.

Exposure range Latitude de pose When the subject is not very contrasty, a small error in determining the exposure does not affect the result obtained. An emulsion that can withstand large contrasts is considered to have a large exposure range. Contrasting emulsions and color films have a very weak exposure range, so it is necessary to expose them to the optimal value.

Tampon solution A stabilizing solution specifically designed to maintain a constant pH (see the last word
in the glossary) despite the presence of an acidic or alkaline solution. For example, a borax-boric acid reagent maintains its effectiveness despite the formation of bromine hydrochloric acid

liberated by the reduction of silver bromine in the reagent.

Optical axis An imaginary line passing through the optical center of each objective lens.

Viseur An optical device for photographic cameras that allows the subject to be seen in the same framing

of the image to be recorded on the negative, direct vision (large format camera) and reflex camera) are the only ones that ensure with extreme precision the identity of the visible image and the image

recorded.

Reference or reducer Réducteur A chemical body that is greedy for oxygen, in a certain sense, reducing agents are the developing materials that oxidize at the same time and reduce silver bromine to metallic silver.

Filter A glass plate with two parallel surfaces, which has the property of absorbing some light rays, and in general, a colored filter allows the rays that form its color to penetrate it and absorb the other colors.

Correction filter A colored filter with a low density used to correct the dominance of a color in a color image, whether when photographing, or when enlarging and printing on color photographic paper.

Subject Illuminations Lesson Etendu des luminances du subject or (subject contrast) The difference between the maximum illumination (high light) and the minimum illumination (shadows) of the subject.

Anti-reflective treatment Traifement antircflets The rays reflected from the surfaces in contact with the air - glass of the objective lenses are lost when forming the image - and by treating these surfaces specifically, i.e. covering them with a thin layer of transparent light-reflecting material, the intrusive light is prevented from entering the device and the captured images are more contrasted. All current objective lenses are treated with anti-reflectives.

Refractive index Indice de refraction or (refractive index) A numerical value that characterizes the ability of a transparent material to deflect light.

Accelerator is the name given to a basic (alkaline) body used in developing solutions, as much as the developer contains accelerator, the more active and effective it is.

Distance Hyperfocale The distance at which the first level of clarity is found when the distance is set to infinity. If we set the distance to the hyperfocal distance, the depth of field extends from the middle of the hyperfocal distance to infinity.

Emulsion The name given to a light-sensitive layer of photographic material. Black and white emulsion is composed of silver halogen particles suspended in gelatin.

Emulsion inversible It is an emulsion that can directly produce a positive image, without the mediation of a negative image. Color films for positive slides are of the same group.

Focal plane Plan Focal plane The plane where the image forms the subject at infinity. Sensitive plane Plan-film Sensitive film cut into a rectangular shape for use in the negative tray of large format cameras.

A quartz-halogen lamp (or quartz-iodine lamp) (or iodine ring) is a glowing light bulb and a tungsten filament made in the form of a small balloon or quartz cylinder. The iodine (and sometimes bromine) values ​​in the shell combine with tungsten vapors to give a permanent activation of the filament and the quartz-halogen lamp gives continuous light throughout its life.

Aplanat ou aplanétique Corrector A lens that is completely corrected for spherical aberration.

Apochromatique Corrector A lens that is completely corrected for chromatic aberration, clarity is assured in the three basic components of the color spectrum.

Affaiblisseur A chemical bath capable of reducing the density of the image of the Farmer's Affaiblisseur mentioned below.

Affaibblisseur de Farmer A solution containing a mixture of potassium ferrocyanur and sodium hyposulphite to reduce the density of a negative or printed image on paper.

Affaiblisseur proportionnel A reducer that reduces the densities of images in proportion to the contrast of the negative image, but the overall contrast remains constant.

Development or reducing agent Développateur A reducing agent that has the ability to convert silver halogen imprinted on a light-sensitive layer into metallic silver.

Development Révélateur A basic reducing solution that allows the latent image to be revealed.

Image size Format The dimensions of a sensitive area imprinted in a photocopier, and more generally, the dimensions of a photographic image.

Actinometre An ancient basis for measuring exposure based on the principle of comparing a specific density with the time taken by light to enable an emulsion to blacken directly to the same density.

Exposure meter Posemètre A device for measuring the illumination of a subject, the values ​​are translated into exposure factors, i.e. aperture and shutter speed, corresponding to the sensitivity of the film used. The exposure meter can be independent or integrated into the camera, and in automatic machines the instructions provided by the integrated device are used directly to determine the exposure and automatically adjust whether the aperture or shutter speed.

Durcisseur See (tint).

Condenser Condenser A set of two flat convex lenses used to direct and distribute light evenly in magnifiers.

Soufflet A flexible, accordion-like device that connects the two bodies of the camera, and the name is also given to the zoom bellows used in single-lens reflex cameras to increase the clouds.

Characteristic curve Courbe caracteristique A drawing showing the darkening of a photographic emulsion according to the exposure.

Field curve Courbure de champ Optical aberration gives a concave spherical image The flat is something perpendicular to the optical axis.

Perspective Geometric (or linear) perspective can be defined as the natural convergence of parallel lines of a three-dimensional scene, and we know that all horizontal lines converge towards a single line, which is the horizon, and the apparent size of objects is proportional to their distance. Aerial perspective is the result of the atmosphere that weakens the image of distant objects.

Prism A piece of glass made in a prismatic shape that has the property of changing the direction of light. The visible prism is a very important element in single-object reflex cameras.

Montage Fixing the optical image on a holder.

Nodal points Points nodaux Points located on the optical axis of an objective lens where the incoming and outgoing rays are most focused before and after passing through the pupil. Distinguish the nodal point of incidence (subject side) and the nodal point of emission (image side).

Point of view Point de vue Position of the camera lens or the viewer's eyes relative to the subject.

Dye transfer A complex method of producing color photographs by successive normalization of selected color-impregnated bases.

Halo A secondary, built-up image formed in the bright parts of a photograph. The halo is caused by direct light passing directly onto the film and reflecting off the film press in the camera and onto the emulsion holder.

Halogens are semi-metals (chlorine, bromine, iodine) that combine with silver to give silver halogen, which is the light-sensitive material that remains the basis for all photographic media.

Silver halogen Halogénures d'argent A substance resulting from the union of halogen with silver, and the most widely used in photography is silver bromine, but silver chloride and silver iodine provide significant light sensitivity.

Ammonium hyposulfite or (ammonium thiosulfite) is an essential preparation for rapid fixing solutions.

Sodium hyposulfite or (sodium thiosulfite) has the property of dissolving silver halogen and is often used in all fixing solutions known since the beginnings of photography.

Sodium hydroxide Another name for caustic soda, a strong base used in some developing solutions as an active development accelerator.

Hydroquinone is a reducing agent used in most film and paper development solutions, employed with metol (genol) or with phenidone. It is an active and effective reducing agent in an alkaline medium.

Sodium hexametaphosphate is a preparation used to reduce the hardness of lime water.

Position B B is a shutter adjustment so that it opens when the shutter button is pressed and remains open as long as it is pressed.

Position T T is a shutter adjustment so that it opens when the shutter button is pressed, and when we want to return the shutter to its normal position, we must move the position from T to any other position.

Photographic paper Papier photographique is a paper or cardboard holder covered with an emulsion of silver halogen in gelatin. Depending on the nature of the halogens, it accepts different names: Bromor paper for multiple uses and enlargement, Chlorobromor paper used for unit photography by professionals due to its warm gradations and softness, but unfortunately it is slow to react. Positive paper
Colored or reversible coated with three superimposed sensitive layers.

Inactinique refers to a laboratory lighting that does not affect the light-sensitive materials during the normal development time, non-actinic lighting can only be used with non-universal color emulsions (non-panchromatic).

Anastigmat (non-distorting lens) refers to a set of lenses that correct the so-called aberration (astigmatism). Any objective lens is formed of at least three lenses.

Achromatique refers to a set of lenses designed to give a clear image of two basic colors of the spectrum.

Aspheric refers to a lens whose surface is not spherical, allowing some aberration to be corrected without increasing the number of lenses in the objective.

Anhydrous does not contain water.

PH

A numerical value that indicates the acidity or alkalinity of a chemical solution: A value of 7 indicates neutrality. Solutions with a pH between 7 and 14 are alkaline (as high as this value is), and vice versa. Solutions with a value less than 7 are acidic (as low as this value is).