OXIDATION –Chemical combination of oxygen with
other substances. In photography, the loss of activity
of developer solutions is due partly to oxidation of
the developing agent with oxygen in the air and
partly to oxidation with the silver halide during
development. (PIA)
PIXEL–The smallest single picture element with which
an image is constructed. The light-sensitive
elements in a CCD (chip) camera.
PLANE–A surface which has no curvature; a perfectly
flat surface.
PAN (WITH A CAMERA)–During the course of
photographing a scene, to swing the camera around
in such a way as to follow the action. Derived from:
Panorama. Camera pans are commonly described
as slow-pan, fast-pan, swish-pan, and jerky-pan.
PAPER, VARIABLE CONTRAST–Photographic
paper coated with emulsions having contrast
characteristics grading from soft to hard, depending
on the color of the exposing light as modified by a
series of filters supplied for that purpose.
POLARIZER–An optical device for converting
unpolarized, or natural light, into polarized light.
POSITIVE, BLACK AND WHITE–A photographic
image on film, plate, or paper in which light tones
appear light and dark tones are rendered dark
POSITIVE FILM–Photographic film, designed for the
printing of positive transparencies from negatives.
POSITIVE PRINT–A print in which the light and dark
areas as they exist in the original.
PARALLAX–The apparent displacement of an object
seen from different points. Commonly encountered
in photography in the difference between the image
seen in the viewfinder and that actually taken by the
lens.
POTASSIUM BROMIDE (BROMIDE OR
POTASH), KBr–White crystals, very soluble in
water. Used as a restrainer in developing solutions.
Also used in bleaches and clearing solutions.
PERSISTENCE OF VISION–A property of the eye
that consists of an inability to detect the flickering
of a light that exceeds a certain critical frequency.
PERSPECTIVE –The relative size and alignment of
objects as recorded on a plane surface; the illusion
of three dimensions created on a flat surface.
POTASSIUM HYDROXIDE KOH–Caustic alkali
used as an accelerator in photographic developers.
Concentrated solutions are quite caustic and will
attack the skin, causing painful burns. Similar to
sodium hydroxide.
Al-12
PHOTOELECTRIC CELL–A cell that converts light
energy proportionally into electrical energy. It is
used in exposure meters and sound recorders and
reproducers.
POWER, RESOLVING–The measure of the ability of
a lens, a photographic material, or a combination of
both, to distinguish detail under certain specific
conditions, among which are the shape and contrast
of the target, the quantity of illumination, the
exposure and the method of processing. The
measure of this ability is expressed in lines per
millimeter or in angular resolution of a lens.
PHOTOMETER –An instrument for measuring the
visual intensity of light, specifically for comparing
the relative intensities of light emitted from
different sources of illumination. (PIA)
PREROLL–To start a videotape and let it roll for a few
seconds before it is put in the playback or record
mode, so the electronic system has time to stabilize.
PICKUP TUBE–The imaging device of a video camera
that converts light into electrical energy-the video
signal.
PRESERVATIVE–The ingredient of a photographic
developer that protects it from rapid oxidation.
PINHOLE–(l) Term applied to tiny spots in a
photographic negative; usually produced as the
shadow of a dust particle during exposure, more
rarely the result of chemical dust contamination or
gas bubble formation in the gelatin layer due to
improper processing. (2) Tiny or white or clear areas
in a print or drawing material.
PRINTER, CONTACT–A photographic printer in
which the negative is held in contact with print
material during the exposure. The image of a print
made with a contact printer is the same size as the
image in the negative.
PINT, LIQUID–A unit of capacity equal to 16 fluid
ounces, or 473.17 milliliters.
PRINTER, PROJECTION–A photographic printer in
which the negative is positioned some distance from
the print material; the image being projected onto
the print material. The image of a print made with a
projection printer is usually larger than the image in
the negative.
