Light tight test: Coin test

Question 1

The coin test

Answer 1

is carried out to check the efficiency of the filter + covering on the daylight loader on an automatic processor or the integrity of the dark room

Question 2

1.

Answer 2

the unexposed, unwrapped film is placed on floor of the daylight loader or on clean work surface in dark room

Question 3

2.

Answer 3

a coin is placed on the film, under day light loader/filter + safe light is switched on - left for 30 secs

Question 4

3.

Answer 4

the film is then processed, if outline of coin can be seen - either the safety light is not safe or the daylight loader is leaking light

Question 5

Extended coin test

Answer 5

a more precise test where a row of coins are placed on an unexposed film, which is then covered with dark paper.

Question 6

Extended coin test

Answer 6

one coin is exposed to filter/light one at a time after 30 second intervals
the result in the first coin being exposed for longer, therefore, if there is a leak the outline of the first coin will be more defined than the last

Question 7

Dark room tests

Answer 7

if using dark room, this need to be light tight.

the easiest, cheapest option is to: shut the door, turn the lights off + look for leaks

Question 8

The safe light or filter

Answer 8

should be checked annually to ensure it is not scratched or damaged, the bulb should be 15 watts or less.