Chapter 8 Chemical Processing Chemical Process Development Flashcards
The theory of film development refers to the principle in photography that explains how the latent image in the
exposed film is converted into a negative image (visible image).
Film development
Stages of Film Development are?
Preda velopment water rinse (optional)
Developing (actual) 60 seconds
Stop bad rinse bath 10 seconds
Fixing bath or fixing 30 seconds
Washing
Drying
This is done by simply looking the film in water for 2 to 3 minutes while agitating the water container for every 20 seconds
Development water rinse
Covering the exposed image on the film into actual image
Developing actual 60 seconds
The chemical contents are?
a. Reducer – metol – hydroquinone
b. Accelerator- borax, sodium carbonate, sodium hydroxide
c. Restrainer – potassium bromide
d. Preservative – sodium sulphite, sodium bisulphate
The removal of the traces of the developer as well as it helps in the removal of excess or undeveloped silver
halides.
Stop Bath – Rinse Bath (10 seconds0
Even after developing, the image is still invisible because the silver halides are still present in the emulsion.
Fixing Bath or Fixing (30 seconds)
Fixing Bath or Fixing (30 seconds)
Ingredients are:
a. Fixer – hypo (sodium thiosulfate)
b. Neutralizer – acid (acetic acid)
c. Preservative – sodium sulfite
d. Hardener – potassium alum
The three forms of rinse bath are:
a. Water Rinse Bath
b. Acid Rinse Bath
c. Hardening Rinse Bath
This is the final part of the processing cycle, which removes the residual chemicals and soluble silver
compounds from the emulsion and reveals the image.
60 seconds only
Washing
Developing Chemicals are?
Reducing Agent
Accelerator
Preservative
Restrainer
The commonly used preservative is Sodium Sulfite. It prevents stain and makes the developing solution more stable and long lasting.
Preservative
This chemical restrains the action of the exposed areas of the film and permits control of density and contrast.
Restrainer
The most important chemical in any developing agent
Reducing Agent
The purposes of accelerators are to energize the reducing agents and they soften and swell the emulsion to
permit the developer to penetrate deeply and quickly
Accelerators
Fixing Chemicals
Sodium Thiosulfate
Acetic Acid (28%)
Sodium Sulfate
Potassium alum
Boric acid
This refers to fixing chemical commonly called “hypo”, it is one which dissolves the unexposed silver
halides.
Sodium Thiosulfate
This refers to fixing chemicals that is used to neutralize the developer.
Acetic Acid (28%
This refers to fixing chemical that is added to acetic acid to neutralize the developer but causes the hypo to break down, liberating sulfur
Sodium Sulfate
This refers to fixing chemicals that is added to the fixing bath because it has the ability to toughen or harden
the emulsion.
Potassium Alum
This refers to the fixing chemical that is added to slow the action and prolong the usefulness of the bath
Boric acid
Developer formulation are?
Typical component
Solvent
developing agent
preservative
acceleration or activator
restrainer
Developer formulation
Fixing but formula are?
Water
dissolving agent
Preservative
Neutralizers
Hardener
Kinds of printing are?
Contact printing
Projection printing
This refers to the evolution side of the negative that is exposed in contact with the emulsion of sensitized paper producing a print image of the same size as that of the negative
Contact printing
This refers to the image in the negative that may be enlarged or reduced
Projection printing
Equipment for paper developing are?
- Three plastic trays – one each for the developer, stop-bath, and the fixer. (The size of the tray is determined by
the largest prints size). - Metal, plastic, or bamboo tong preferably with rubber ends to hold the prints.
- Rubber (surgical) hand gloves.
- Timers
- Paper cutter
- A bigger tray or tank for washing prints
