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Stack #174106
processing
Question | Answer |
---|---|
what are sequestering agents? | chelates, added to soften water |
what are the two developing agents? | phenidone and hydroquinone |
is phenidone quick or slow acting? | quick acting |
does hydroquinone produce black tones or shades of gray? | black tones ( high contrast) slowly |
what is the purpose of buffering agents? | to maintain pH of solution, sodium carbonate |
what is potassium bromide? | a restrainer, anti foggant |
what does a preservative do? | reduces oxidation and maintains balance among developing agents. |
name two preservatives | sodium sulfite or potassium sulfite |
what is glutaraldehyde? | a hardener that prevents excessive swelling of film emulsion so it can be transported easily thru the rollers |
purpose of replenisher | to maintain consistent developer and fixer solution activity-has a higher pH than working developing solution. |
purpose of starter solution | acidic restrainer, needed after cleaning and fresh developer replenisher is added.reduces pH to normal |
what are the factors affecting development? | time, temp, and fresh chemistry ( pH) |
What will a slight increase in temperature cause? | increased density, slight in crease in chemical fog, increase in contrast |
What will a severe rise in temp cause? | gross increase density, unacceptable increase in chemical fog, and decreased contrast |
If the temperature is not corrected, what happens to the developer? | the developer becomes exhausted and results in decreased density and low contrast |
what is the function of the Fixer? | to stop any further development. |
What is the name of the fixing agent? | Ammonium thiosulfate ( removes undeveloped silver halide) |
What does activator do? | stops dichroic fog by stopping developer action |
what hardens emulsion to limit H2O uptake? | potassium alum |
what is sodium acetate? | a buffer that controls pH |
How long is fixing time? | approx 15 seconds |
What is the function of washing? | to remove silver complexes and ammonium halides so film does not turn yellow brown |
what occurs due to inadequate washing | hypo retention |
What factors affect drying time | squeegee rollers, air humidity,air temp,air circulation |
types of rollers | entry rollers,guide plates, turn round rollers at bottom,crossover rollers b/t racks at top, squeegee rollers b/t tanks |
how long is the processing time | 90 seconds ( 26s, dev.,15s fix, 15s wash, 24s dry., 10s travel ) |
the principle contributor to adequate agitation of developer and fixer is ? | recirculation system |
how is the developer cooled? | piping routed thru bottom of cold water cools the developer |
if developer replenishment rate is increased, what happens to image? | slight increase in contrast |
if replenishment rate is decreased what happens to image? | significant decrease in contrast |
why is silver recovery important? | anti pollution |
what should be done for monthly maintenance? | drain and clean tanks, refill with fresh chemistry, close drain vavles, turn main power off |