CHAPTER 8 Flashcards
The theory of film development refers to the principle in photography that EXPLAINS HOW THE LANTEN IMAGE in the exposed film is converted into a negative image
Film Development
Stages of Film Development:
- Predevelopment Water Rinse
- Developing
- Stop Bath – Rinse Bath
- Fixing Bath or Fixing
- Washing
This is done by SIMPLY SOAKING THE FILM in water for 2 to 3 minutes while agitating the water container for every 20 seconds.
Predevelopment Water Rinse
Converting the exposed image on the film INTO ACTUAL IMAGE
Developing
The chemical contents are:
a. Reducer
b. Accelerator
c. Restrainer
d. Preservative
This is performed by SOAKING THE FILM IN THE DEVELOPER
Developing
Exposed film affects the SILVER HALIDES BUT THE CHANGE IS INVISIBLE
Developing
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
This PROCESS STOP DEVELOPMENT by neutralizing the effects of the developer
Stop Bath – Rinse Bath
It is also necessary to MINIMIZE THE STAINING EFFECT of the developer and at the same time conserve to some extent the strength of the
fixing solution
Stop Bath – Rinse Bath
The three forms of rinse bath are:
a. Water Rinse Bath
b. Acid Rinse Bath
c. Hardening Rinse Bath
is required to loosen the silver halides from the unexposed halides so THEY CAN BE WASHED AWAY
Fixing Bath
also MAKES THE IMAGE PERMANENT in white light
Fixing 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.
Washing
Developing Chemicals:
- Reducing Agent
- Accelerators
- Preservative
- Restrainer
The MOST IMPORTANT CHEMICAL in any developing agent
Reducing Agent
It is the one that REDUCES THE EXPOSED HALIDES into visible metallic silver
Reducing Agent
The two chemicals mostly used are:
(1) hydroquinon
(2) Metol.
The commonly used PRESERVATIVE IS SODIUM SULFITE
Preservative
The purposes of accelerators are to ENERGIZE THE REDUCING AGENT and they soften and swell the emulsion to permit the developer to penetrate deeply and quickly
Accelerators
The three kinds of accelerators are:
Sodium Carbonate
Sodium Hydroxide
Borax
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
Fixing Chemicals:
- Sodium Thiosulfate
- Acetic Acid
- 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 CHEMICAL THAT IS USED TO NEUTRALIZE THE DEVELOPER
Acetic Acid
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
It is added because it combines with the sulfur to form NEW HYPO
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
