Processing kodak motion picture films, module 3 analytical procedures

PROCEDURE C
Determination of Silver in Thiosulfate Fixing Baths
When Concentration of Silver is Less Than
0.5 Grams per Liter.
Note: When the concentration of silver is less than 0.5 g/L,
it is possible to establish the silver content between two
concentrations 0.05 g/L apart, using only graduated
cylinders and the markings on the cylinders for all
measurements.
Treatment of Sample
1. Obtain several 100-mL glass-stoppered graduated
cylinders. Add to each 40 mL of fixing bath sample,
20 mL of 0.2 M potassium ferricyanide, and 20 mL of
6 N accelerator reagent. Stopper and shake to mix.
2. Add from a polyethylene squeeze bottle to one of the
cylinders, 20 mL of 0.00926 N thioacetamide, and to a
second cylinder, add 10 mL.
Note: 20 mL of 0.00926 N thioacetamide is equivalent
to 0.5 g/L of silver and 10 mL is equivalent to
0.25 g/L of silver.
3. Stopper and shake the cylinders vigorously for 5
seconds.
4. Filter approximately 20 mL of the contents of each
cylinder through Whatman No. 3 (12.5 cm diameter)
filter paper and collect the filtrates in beakers
containing approximately 5 mL of 0.00926 N
thioacetamide each.
5. Observe the appearance of the contents and refer to
Table 3, Decision Sheet for Procedure C
(40 mL Sample), to make the next decision.
Reporting Results
1. These two trials determine that:
a. The procedure is not applicable (silver content is
greater than 0.5 g/L)
b. The silver content is below 0.25 g/L
c. The silver content is between 0.25 and 0.5 g/L
2. If the procedure is applicable, three or fewer trials will
establish the silver content between two silver
concentrations 0.05 grams per liter apart.
Table 3 Decision Sheet for Procedure C (40 mL Sample)
mL of
0.00926 N
Thioacetamide
Added
If the Contents of
the Beaker
Turns Color,
Amount of Silver in
Fix is More Than
2 0.05 g/L
4 0.10 g/L
6 0.15 g/L
8 0.20 g/L
10 0.25 g/L
12 0.30 g/L
14 0.35 g/L
16 0.40 g/L
18 0.45 g/L
20 0.50 g/L
If the Contents of
the Beaker
Remains Clear,
Amount of Silver in
Fix is Less Than
PROCEDURE D
Determination of Exhaustion of Kodak Chemical
Recovery Cartridge
Note: When the concentration of silver in the effluent from
the Recovery Cartridge exceeds 0.25 grams per litre, it can
be assumed that the capacity of the cartridge has been
exceeded. By selecting the 10 mL of 0.00926 thioacetamide
(equivalent to 0.25 g/L of silver) and making only the one
trial, a decision on exhaustion can be reached.
Treatment of Sample
1. Place in a 100-mL glass-stoppered graduated cylinder
40 mL of fixing bath sample, 20 mL of 0.2 M
potassium ferricyanide, and 20 mL of 6 N accelerator
reagent. Stopper and shake to mix.
2. Add 10 mL of 0.00926 N thioacetamide, stopper, and
shake for 5 seconds.
3. Filter approximately 20 mL of the mixture through a
Whatman No. 3 filter paper into a beaker containing
approximately 5 mL of 0.00926 N thioacetamide.
Reporting Results
1. Colored, the recovery cartridge is exhausted.
2. Clear, the recovery cartridge is still serviceable.
4 Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03