EVALUATION AND INTERPRETATION
a. Count the number of step differences.
Between the master film and the test films.
(a) On the master film, step 7 has a density of 1.0. Test film number
two, step three has a density of .97.
(b) The difference of steps would be the master film, step 7 minus the
test film number 2, step 3 = 4 minus the step difference.
b. Divide this number:
Into 0.3 (the factor required to double-film density).
For example: 0.3/4 = .075 (the log exposure change between each
It would normally require a step difference of 2 to equal a 15 percent change.
c. Make a change of screens if more than 2 step differences exist between the
master and the test film.
Perform the film-screen combination test on a quarterly basis and upon
acquisition of new screens.
a. Check film-screen combination within a five-speed group, which does not
meet the above criteria.
b. Determine the cause.
c. For example:
Misidentification of the cassette, that is, the type of screens it contains.
(2) Screens with the same speed that were made by different
Poor screen contact.