تويت
المرشد خطوة بخطوة للتصوير الفوتوغرافي .. المصطلحات الحرف / A - B/
Glossary
Terms in italics denote useful cross- references to other glossary entries .
/ A /
Aberration The inability of a lens to produce a perfect image in shape and sharpness even when it is focused correctly on a subject . Aberrations are greatly reduced by the compound construction of lenses but the degree of correction varies according to lens quality .
Accelerator An ingredient of developer normally an alkali- which speeds up development by quickening the action of the reducing agent in the solution .
Actinic The ability of light to change the nature of materials exposed to it .
Acutance Objective , physical measurement of the sharpness of a processed photographic image .
Additive color synthesis Way of producing complete color images ( with white ) by mixing light of the three primary colors , red , blue and green in appropriate proportions .
Additive systems Systems of color reproduction based on reproducing naturally occuring colors by mixing three primary colored lights .
Aerial perspective The increase of apparent depth in a landscape due to changes of tone with distance . This is caused by the presence of haze or smoke which creates extraneous ultra - violet light .
Agitation Method of keeping fresh processing solution in contact with the emulsion surface during photographic processing .
Airbrush A retouching instrument which uses compressed air to spray liquid color .
Anamorphic lens Lens which compresses or " squeezes " the image in one plane . Rectangular pictures can be recorded as square images .
Anastigmat Lens containing a number of elements in a compound structure that reduces optical aberrations , particularly astigmatism .
Angle of incidence The angle formed between an incident ray of light striking a surface and an imaginary line running perpendicular to the surface , known as the normal . The angle of incidence equals the angle of reflection .
Angle of reflection The angle formed between a reflected ray of light and an imaginary line running perpendicular to the surface at the point of reflection - known as the normal . The angle of reflection equals the angle of incidence .
Angle of view The widest angle of acceptance of light rays by a lens which still gives a full format image on the film plane of usable quality .
Anti - halation layer Light - absorbing dye within , or on the back of the film base , or between the base and the emulsion , that absorbs light which . has passed through the emulsion . See also halation .
Aperture Opening within or close to a lens . Allows control of the amount of light passing through the lens , and is therefore usually variable in diameter . This diameter is calibrated infnumbers .
ASA Denotes American Standards Association and indicates the speed rating or sensitivity to light , of film . The higher the ASA number , the faster the speed of the film . The ASA scale is based on an arithmetical progres- sion where 400 ASA film , for example , is twice as fast as 200 ASA film .
Astigmatism Lens aberration where parallel rays of light passing through the lens obliquely come to focus as a line rather than a point .
Automatic exposure control System of exposure setting in a camera in which the electric current produced or inhibited by the action of light on a photo - electric cell operates a mechanism that adjusts the aperture or shutter speed automatically .
/ B /
Back focus The distance between the vertex of the back surface of the lens and the focal plane . This is not always equal to the focal length as is the case with telephoto and retro- focus lenses .
Back lighting Artificial or natural lighting coming toward the camera from behind the subject .
Back projection Projection of a picture on to the back of a translucent screen . Subjects can be placed in front of the screen and will appear superimposed against the projected background picture . Lighting and color intensity have to be balanced if the foreground subject is to match the projected image .
Bag bellows A short , flexible sleeve which replaces the normal bellows when using a short focal length ( wide - angle ) lens on a large format camera .
Barn doors Masking accessory for studio lamps which controls the direction and width of light by the movement of hinged flaps .
Barrel distortion Lens aberration which causes lines parallel to the picture edges to appear to bend inward as they approach the corners .
Baryta Coating of barium sulfate between the base and emulsion of
non - resin coated photographic paper to provide a smooth white . and chemically inert barrier .
Base The backing of a film which supports the photographic emulsion . It is usually made from paper , plastic or glass .
Bas - relief A technique where a contact positive ( on sheet film ) and its negative are sandwiched slightly off register in the negative carrier of the enlarger . Resulting prints look like side - lit embossed images .
Batch numbers Serial numbers stamped on packs of sensitized materials to indicate particular batches of emulsion .
Bellows Light - tight , folding sleeve which can be fitted between the lens and the film plane for close - up work .
Between the lens shutter Diaphragm shutter placed within the components of a compound lens near to the aperture diaphragm .
Bi - concave lens Single lens element where both its faces curve inward toward the optical center , causing light rays to diverge .
Bi - convex lens Single lens element where both its faces curve outward away from the optical center , causing light rays to converge .
Binocular vision Visually , the ability to determine three dimensions from the parallax effect created by two eyes .
Bleach Chemical bath which converts the black and white silver image created by exposure back to a halide . Bleaching is a preliminary step in most toning , reducing and color processing .
Bleed off To print a photograph so that one or more sides is flush to the edge of the paper .
Blocking out Painting out unwanted backgrounds on a negative with an opaque liquid before printing .
Blooming Putting a transparent coating on to the surface of a lens so that surface reflection is eliminated through destructive interference of the waves of light .
Bounce flash Directing flash to illuminate a subject indirectly by reflection ( usually off a ceiling or a wall ) . It gives diffused lighting quality .
Bracketing In exposure , taking a series of pictures of the same subject that vary only in the exposure given . For example , correct , half , and double estimated correct exposure .
Bright line viewfinder Viewfinder in which the subject area is outlined by a white line frame . It may similarly show parallax correction marks .
Brightness range The difference in luminance between the lightest and darkest areas in a subject , or an image .
Bromide paper Most common type of black and white photographic paper used for printing and enlarging . Its light - sensitive emulsion consists mostly of silver bromide .
B setting A shutter setting indicating that the shutter will remain open as long as the shutter release button remains depressed .
Burning in Another term for Printing - in .
Glossary
Terms in italics denote useful cross- references to other glossary entries .
/ A /
Aberration The inability of a lens to produce a perfect image in shape and sharpness even when it is focused correctly on a subject . Aberrations are greatly reduced by the compound construction of lenses but the degree of correction varies according to lens quality .
Accelerator An ingredient of developer normally an alkali- which speeds up development by quickening the action of the reducing agent in the solution .
Actinic The ability of light to change the nature of materials exposed to it .
Acutance Objective , physical measurement of the sharpness of a processed photographic image .
Additive color synthesis Way of producing complete color images ( with white ) by mixing light of the three primary colors , red , blue and green in appropriate proportions .
Additive systems Systems of color reproduction based on reproducing naturally occuring colors by mixing three primary colored lights .
Aerial perspective The increase of apparent depth in a landscape due to changes of tone with distance . This is caused by the presence of haze or smoke which creates extraneous ultra - violet light .
Agitation Method of keeping fresh processing solution in contact with the emulsion surface during photographic processing .
Airbrush A retouching instrument which uses compressed air to spray liquid color .
Anamorphic lens Lens which compresses or " squeezes " the image in one plane . Rectangular pictures can be recorded as square images .
Anastigmat Lens containing a number of elements in a compound structure that reduces optical aberrations , particularly astigmatism .
Angle of incidence The angle formed between an incident ray of light striking a surface and an imaginary line running perpendicular to the surface , known as the normal . The angle of incidence equals the angle of reflection .
Angle of reflection The angle formed between a reflected ray of light and an imaginary line running perpendicular to the surface at the point of reflection - known as the normal . The angle of reflection equals the angle of incidence .
Angle of view The widest angle of acceptance of light rays by a lens which still gives a full format image on the film plane of usable quality .
Anti - halation layer Light - absorbing dye within , or on the back of the film base , or between the base and the emulsion , that absorbs light which . has passed through the emulsion . See also halation .
Aperture Opening within or close to a lens . Allows control of the amount of light passing through the lens , and is therefore usually variable in diameter . This diameter is calibrated infnumbers .
ASA Denotes American Standards Association and indicates the speed rating or sensitivity to light , of film . The higher the ASA number , the faster the speed of the film . The ASA scale is based on an arithmetical progres- sion where 400 ASA film , for example , is twice as fast as 200 ASA film .
Astigmatism Lens aberration where parallel rays of light passing through the lens obliquely come to focus as a line rather than a point .
Automatic exposure control System of exposure setting in a camera in which the electric current produced or inhibited by the action of light on a photo - electric cell operates a mechanism that adjusts the aperture or shutter speed automatically .
/ B /
Back focus The distance between the vertex of the back surface of the lens and the focal plane . This is not always equal to the focal length as is the case with telephoto and retro- focus lenses .
Back lighting Artificial or natural lighting coming toward the camera from behind the subject .
Back projection Projection of a picture on to the back of a translucent screen . Subjects can be placed in front of the screen and will appear superimposed against the projected background picture . Lighting and color intensity have to be balanced if the foreground subject is to match the projected image .
Bag bellows A short , flexible sleeve which replaces the normal bellows when using a short focal length ( wide - angle ) lens on a large format camera .
Barn doors Masking accessory for studio lamps which controls the direction and width of light by the movement of hinged flaps .
Barrel distortion Lens aberration which causes lines parallel to the picture edges to appear to bend inward as they approach the corners .
Baryta Coating of barium sulfate between the base and emulsion of
non - resin coated photographic paper to provide a smooth white . and chemically inert barrier .
Base The backing of a film which supports the photographic emulsion . It is usually made from paper , plastic or glass .
Bas - relief A technique where a contact positive ( on sheet film ) and its negative are sandwiched slightly off register in the negative carrier of the enlarger . Resulting prints look like side - lit embossed images .
Batch numbers Serial numbers stamped on packs of sensitized materials to indicate particular batches of emulsion .
Bellows Light - tight , folding sleeve which can be fitted between the lens and the film plane for close - up work .
Between the lens shutter Diaphragm shutter placed within the components of a compound lens near to the aperture diaphragm .
Bi - concave lens Single lens element where both its faces curve inward toward the optical center , causing light rays to diverge .
Bi - convex lens Single lens element where both its faces curve outward away from the optical center , causing light rays to converge .
Binocular vision Visually , the ability to determine three dimensions from the parallax effect created by two eyes .
Bleach Chemical bath which converts the black and white silver image created by exposure back to a halide . Bleaching is a preliminary step in most toning , reducing and color processing .
Bleed off To print a photograph so that one or more sides is flush to the edge of the paper .
Blocking out Painting out unwanted backgrounds on a negative with an opaque liquid before printing .
Blooming Putting a transparent coating on to the surface of a lens so that surface reflection is eliminated through destructive interference of the waves of light .
Bounce flash Directing flash to illuminate a subject indirectly by reflection ( usually off a ceiling or a wall ) . It gives diffused lighting quality .
Bracketing In exposure , taking a series of pictures of the same subject that vary only in the exposure given . For example , correct , half , and double estimated correct exposure .
Bright line viewfinder Viewfinder in which the subject area is outlined by a white line frame . It may similarly show parallax correction marks .
Brightness range The difference in luminance between the lightest and darkest areas in a subject , or an image .
Bromide paper Most common type of black and white photographic paper used for printing and enlarging . Its light - sensitive emulsion consists mostly of silver bromide .
B setting A shutter setting indicating that the shutter will remain open as long as the shutter release button remains depressed .
Burning in Another term for Printing - in .
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