Flashcards in Midterm 2 Deck (61)
List the darkroom essentials
Film identification printer
Safelights must not exceed ___ watts
Safelights must be at least ___ feet away from work area
Undeveloped film must not be exposed to safelights more than ___ minutes
Safelights usually only allows light from the ____ end of visible light spectrum?
Red (GBX filter)
_______ consists of incrementally exposing undeveloped film to dark room conditions in 30 sec intervals for up to 3 minutes.
Safe light test
What are the steps of film development?
What part of film development/image creation is when the film is exposed to light?
Note: 99% of the image is created by light emanated by screens. 1% or less comes from direct exposure of silver halide crystal by an x-ray photon
Exposure of the film causes silver bromide crystal to what?
Separate into a silver ion and a bromine ion
What step of film development is the latent image created?
What does the developer do in film development?
Donates electrons that create elemental silver
Note: black in color
Between developer and fixer, what happens?
Wash stop bath to remove excess developer
What does fixer do in film development?
Remove unexposed silver halide crystals from emulsion.
Permanently stops exposure beyond what has been done prior to developer
What does the final wash do in the film development process?
Clears all chemicals on the film surface and emulsion.
Prevents fixer chemicals from continuing to cause chemical changes to emulsion after the finished product has been produced.
What happens in the film development process if washing was not good enough?
Overtime the film degrades: brown color, acetic acid smell, etc
What pH is developer?
pH 10-11.5, strong base
What is in developer?
What does “activator” do in developer solution and what is it?
Softens gelatin protective cover on film, Makes alkaline pH at >7
What do the “reducing agents” do in developer solution and what is it?
Hydroquinone or Phenidone (Metal or Elon)
Reduces EXPOSED silver halide to black metallic silver
What does the “preservative” do in developer solution and what is it?
What does the “restrainer” do in developer solution and what is it?
Potassium bromide, acetic acid
Prevents chemical fog in new developer
What is in the fixer solution?
What does the “clearing agent” do in fixer solution and what is it?
Dissolves undeveloped silver halide, removes it from emulsion
What does the “tanning agent” do in fixer solution and what is it?
Shrinks, hardens, preserves emulsion
What does the “activator” do in fixer solution and what is it?
Neutralizes developer, stops the development process, maintains acid pH
Processing is a function of 3 T’s
What causes film overdevelopment?
Increased time, temp or titration.
Note: overdevelopment = darker film
Film overdevelopment is caused by processor-induced fog which is the forced development of
unexposed silver halide crystals by too much processing
Manual processing: ___˚F, and list time for development, fixer, wash, dry
5 min development
10 min fixer
20 min washing
20-40 min drying
Summary: estimated 1 hour total for each film in manual processing