ISO 417:1993
(Main)Photography — Determination of residual thiosulfate and other related chemicals in processed photographic materials — Methods using iodine-amylose, methylene blue and silver sulfide
Photography — Determination of residual thiosulfate and other related chemicals in processed photographic materials — Methods using iodine-amylose, methylene blue and silver sulfide
Photographie — Détermination du thiosulfate résiduel et d'autres produits chimiques dans les produits photographiques traités — Méthodes à l'iode-amylose, au bleu de méthylène et au sulfure d'argent
General Information
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Standards Content (Sample)
I
I NTE R NAT I O NA L
IS0
STANDARD 41 7
Second edition
1993-04-1 5
Photography - Determination of residual
thiosulfate and other related chemicals in
processed photographic materials -
Methods using iodine-amylose, methylene
blue and silver sulfide
Photographie - Détermination du thiosulfate résiduel et d’autres produits
chimiques dans les produits photographiques traités - Méthodes à
I’iode-amylose, au bleu de méthylène et au sulfure d‘argent
--
Reference number
IS0 417:1993(E)
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IS0 417:1993(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 41 7 was prepared by Technical Committee
42, Photography.
ISO/TC
This second edition cancels and replaces the first edition (IS0 41 7:1977),
which has been technically revised. It now contains an iodine-amylose
method which can generally be used with film and paper and which should
be used with film and paper containing incorporated developing agents.
Annexes A, B, C, D, E and F of this International Standard are for infor-
mation only.
O IS0 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 4 CH-1211 Genève 20 Switzerland
Printed in Switzerland
ii
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IS0 417:1993(E)
Introduction
This International Standard is one of a series of specifications on photo-
graphic processing. This International Standard may occasionally be used
by individuals without a working knowledge of analytical chemistry. Hazard
warnings have therefore been given using a system of symbols with letter
codes designating the nature of the hazard. More detailed information re-
garding hazards, handling and use of these chemicals may also be avail-
able from the manufacturer.
I Determination of residual thiosulfate and its decomposition products is of
use in appraising the adequacy of washing and therefore the permanence
of the silver image on photographic film, plates and paper. Inadequate
washing can cause a loss in image density and the formation of stain in
low-density areas. These deleterious effects are accelerated by improper
storage conditions.
Determination of residual thiosulfate and related compounds, by itself, is
not sufficient to insure the permanence of photographic records. Long-
term or archival storage requires the proper attention to enclosure ma-
terials, storage environment, and the like. These considerations are
specified in IS0 3897, IS0 5466, IS0 6051 and IS0 10602.
iii
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INTERNATIONAL STANDARD
IS0 417:1993(EI
Photography - Determination of residual thiosulfate
and other related chemicals in processed photographic
materials - Methods using iodine-amylose,
methylene blue and silver sulfide
1.6 The silver sulfide densitometric method meas-
1 Scope
ures thiosulfates, polythionates and all other residual
chemicals in a processed product that react with silver
1 .I This International Standard specifies test meth-
ion to form a silver "stain" under the conditions of the
ods for the determination of residual thiosulfate and
test.
related compounds in processed photographic ma-
terials. NOTE 2 This method requires a photometer or
spectrophotometer capable of operating in the reflectance
mode.
1.2 It applies to silver halidelgelatin products that
have been processed with a final thiosulfate fixing
1.7 A tabulated summary of methods, scope, etc. is
bath and a water wash. Stabilized black-and-white
given in annex B.
products are not included. The procedures given in
this International Standard measure residual
thiosulfate, and the silver densitometric method
2 Normative references
measures residual related polythionate materials as
well. Measurements carried out by the procedures
The following standards contain provisions which,
given in this International Standard may, within the
through reference in this text, constitute provisions
B, correlate with
limitations stated in annexes A and
of this International Standard. At the time of publi-
the image stabilities of processed photographs.
cation, the editions indicated were valid. All standards
are subject to revision, and parties to agreements
1.3 Film or plates with photographic-sensitive layers based on this International Standard are encouraged
on both sides, or with a photographic sensitive layer to investigate the possibility of applying the most re-
on one side and a gelatin backing layer on the reverse cent editions of the standards indicated below.
IEC and IS0 maintain registers of cur-
side, may contain approximately twice as much Members of
rently valid International Standards.
thiosulfate after processing as samples having a
coating on one side only. This situation will be true for
IS0 5-3: 1984, Photography - Density measurements
materials for which residual thiosulfate is determined
- Part 3: Spectral conditions.
by the iodine-amylose or methylene blue procedures.
NOTE 1 For the method of reporting such results, see IS0 385-1 : 1984, Laboratory glassware - Burettes -
figure 1, example 3.
Part 1: General requirements.
IS0 648:1977, Laboratory glassware - One-mark
1.4 The iodine-amylose method can be used with
pipettes.
fibre-based paper, film and plates. It is the method to
be used with film and paper containing incorporated
IS0 835-1 :I 981, Laboratory glassware - Graduated
developing agents.
pipettes - Part 1: General requirements.
1.5 The methylene blue method can be used with IS0 835-2: 1981, Laboratory glassware - Graduated
fibre-based paper, film and plates, but not with film pipettes - Part 2: Pipettes for which no waiting time
is specified.
and paper containing incorporated developing agents.
1
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IS0 417:1993(E)
IS0 835-3:1981, Laboratory glassware - Graduated Detailed warnings for handling chemicals and their
pipettes - Part 3: Pipettes for which a waiting time
diluted solutions are beyond the scope of this Inter-
of 15 s is specified. national Standard.
Employers shall provide training and health and
IS0 835-4:1981, Laboratory glassware - Graduated
safety information in conformance with legal re-
pipettes - Part 4: Blow-out pipettes.
quirements.
IS0 1042: 1 983, Laboratory glassware - One-mark
The hazard symbol system used in this International
volumetric flasks.
Standard is intended to provide information to the
users and is not meant for compliance with legal re-
IS0 4788: 1 980, Laboratory glassware - Graduated
quirements for labelling as these vary from country to
measuring cylinders.
country.
It is strongly recommended that anyone using
3 General requirements
these chemicals obtain from the manufacturer
pertinent information about the hazards, hand-
3.1 Safety and hazard concerns ling, use and disposal of these chemicals.
3.1.3 Hazard information code system
3.1.1 Handling
a
Harmful if inhaled. Avoid breathing
Reagents shall be handled in conformity with health
dust, vapour, mist or gas. Use only
and safety precautions as shown on containers or as
with adequate ventilation.
given in other sources of such information. Proper
labelling of prepared reagents includes chemical
Harmful if contact occurs. Avoid con-
name, date of preparation, expiration date, restan-
tact with eyes, skin or clothing. Wash
dardization date, name of preparer, and adequate
thoroughly after handling.
health and safety precautions. The discharge of re-
agents shall conform to applicable environmental
Harmful if swallowed. Wash thor-
regulations.
oughly after handling. If swallowed,
obtain medical attention immediately.
3.1.2 Hazard warnings
<< S >> May be fatal if swallowed. If swal-
lowed, obtain medical attention im-
Some of the chemicals specified in the test pro-
mediately.
cedures are caustic, toxic or otherwise hazardous.
Safe laboratory practice for the handling of chemicals
Will burn. Keep away from heat,
requires the use of safety glasses or goggles, rubber
sparks and open flame. Use with ad-
gloves and other protective apparel such as face
equate ventilation.')
masks or aprons where appropriate. Specific danger
notices are given in the text and footnotes for par-
Oxidizer. Contact with other material
ticularly dangerous materials, but normal precautions
may cause fire. Do not store near
are required during the performance of any chemical
combustible materials.
procedure at all times.
3.2 Reagents
The first time that a hazardous material is noted in the
test procedure section, the hazard will be indicated
Reagents used in the test procedures shall be certi-
by the word "DANGER" followed by a symbol con-
fied reagent-grade chemicals and shall meet appro-
sisting of angle brackets "< >" containing a letter
i
priate standards or be chemicals of a purity acceptable
which designates the specific hazard. A double
for the analysis.
bracket "<< >>" will be used for particularly peril-
ous situations.
NOTE 3 Further details are given in IS0 6353-1,
In subsequent statements involving handling of these IS0 6353-2 and IS0 6353-3.
hazardous materials, only the hazard symbol consist-
ing of the brackets and letter(s1 will be displayed. Whenever water is specified without other qualifiers
Furthermore, for a given material, the hazard symbols in the test procedures, only distilled water or water
will be used only once in a single paragraph. of at least equal purity shall be used.
1) The flammable warning symbol, < F>, will not be used for quantities of common solvents under 1 litre.
2
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IS0 417:1993(E)
3.3 Glassware 4.4 Reagents
All glassware subject to heating shall be of heat-
4.4.1 Potassium iodate, c(KI0,) = 0,000 017 mol/l
resistant borosilicate glass.2)
(0,003 57 g/l)
Pipettes and other volumetric glassware shall meet
Prepare a 0,016 7 mol/l solution of potassium iodate
the volume requirements of Class A or Class B
by weighing 0,357 g of potassium iodate
glassware as specified in IS0 385-1, IS0 648,
(DANGER:), placing it in a 100 ml one-mark
IS0 835-1, IS0 835-2, IS0 835-3, IS0 835-4,
volumetric flask, making up to the mark with water
IS0 1042 and IS0 4788.
and mixing well. Pipette 1,0 ml of the 0,016 7 mol/l
potassium iodate solution into a 1 litre one-mark
volumetric flask, making up to the mark with water.
4 Iodine-amylose method
4.4.2 Formate buffer, pH 2,O
Add, from a graduated cylinder, 11 O ml of formic acid
4.1 Use
(HCO2H) (88-90 %) (DANGER: < C > < B > < S >
< F >) to a 1 litre one-mark volumetric flask containing
The iodine-amylose method is applicable to th de-
500 ml to 600 ml of water, and make up to the mark
termination of residual thiosulfate ions in resin-coated
with water. Using a pH meter, adjust the solution to
(RC) photographic film and paper containing incor-
pH 2,O f 0,1 at 21 OC with 10 moi/l sodium hydroxide
porated developing agents. The method is also appli-
solution (4.4.8) (DANGER: << C >>) from a dropping
cable to measuring residual thiosulfate ion in
pipette.
fibre-based paper, film and plates. This method
measures only thiosulfate ions and gives results
comparable to those obtained by the methylene blue
4.4.3 Formate buffer, pH 2,8
method.
Pipette 10,O ml of pH 2,O formate buffer (4.4.2) into
NOTE 4 The method gives results that correlate well with
a 1 litre one-mark volumetric flask and make up to the
accelerated keeping tests of several processed microfilms
mark with water.
and is applicable to colour as well as black-and-white prod-
ucts.
4.4.4 Eluent
Dissolve 1,0 g f 0,l g of potassium iodide (KI) and
4.2 Principle
1,0 g f 0,l g of potassium monohydrogen phosphate
trihydrate (K2HP0,.3H,0) and dilute to 1 litre with
The eluent (4.4.4) is added to the sample to extract
water. Using a pH meter, adjust to pH 8,5 at 21 "C
residual thiosulfate, tetrathionate and pentathionate
by adding 0,5 moll1 sulfuric acid (4.4.9) dropwise from
a complex with any
ions. Formalin is added to form
a dropping pipette.
sulfite ion present. Iodine is added to an amylose
(fractionated linear potato starch) indicator to form a
blue-coloured solution. The thiosulfate in the eluent, 4.4.5 Cadmium iodide-amylose reagent (Cdl,-
amylose)
when added to the iodine-amylose solution will react
with the iodine and proportionately reduce the inten-
NOTES
sity of the blue colour. The loss in colour corresponds
to the thiosulfate concentration.
5 For an alternate reagent, see annex E.
6 Batches should be limited to 1 litre volumes.
4.3 Chemical reactions
Add and dissolve 11,O g f 1 g of cadmium iodide
a) Starch (C,H,,O,),+ l2 (in KI solution) -+ Blue- (Cdl,) (DANGER: carcinogen3)) in 400 ml of water, and
coloured solution boil gently for 15 min. Add a further 400 mI of water
and heat to boiling. Continue boiling and slowly add,
with stirring, 5,O g of amylose4). Boil and stir for
b) Blue-coloured solution + S203- -+ Decrease in blue
5 min. Continue boiling and slowly add, with stirring,
colour intensity
2) Pyrex@ is an example of suitable glassware available commercially. This information is given for the convenience of users
IS0 of this product.
of this International Standard and does not consitute an endorsement by
3) Zinc iodide (Zni,) has reportedly been used in at least two laboratories to avoid the use of cadmium iodide (CdI,). An
equimolar amount of zinc iodide (9,59 g) is to be used.
4) Examples of suitable commercially available amylose are Aldrich Chemical Company No. 85573-1, ICN Biomedical Inc.
No. 100669, and Sigma No. A0512 (Type 3 from potato). This information is given for the convenience of users of this Inter-
national Standard and does not constitute an endorsement by IS0 of these products.
3
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IS0 417:1993(E)
5,O g of acid-washed analytical filter aid.5) Boil and stir
glassware with an iodide-iodine solution made from
for 5 min. the following reagents.
While the solution is still hot, filter it under a high
Mix 10 ml of potassium iodate solution (4.4.11, 5 ml
vacuum, using a Buchner funnel (4.5.1.5) with the fine
of pH 2,O formate buffer, 5 mI of CdI,-amylose re-
porosity filter paper (4.5.1.6), into a 1 litre vacuum 100 ml of water for a rinsing sol-
agent, and about
flask. Transfer the filtrate to a 1 litre volumetric flask. ution. Rinse glassware first with this solution and then
Rinse the vacuum flask with water and add the
with water.
rinsings to the volumetric flask. Dilute to 1 litre with
water.
4.6 Absorbance of blank solution
4.4.6 Sodium thiosulfate, c(Na2S20,) = 0,100 O
Run a reagent blank before and after the analyses of
mol/l (1 5,8 g/I)”
the samples. If the group of samples is large (greater
than six), also run blanks in the middle of the group.
4.4.7 Formalin (DANGER: < B > < C > < S >)
NOTE 7 In developmental and experimental work,
absorbances of the blank have been between 0,70 and 0,80.
4.4.8 Sodium hydroxide, c(Na0H) = 10 mol/l
(DANGER: << C >>)
The blank absorbance is obtained by adding all the
This solution can be prepared from sodium hydroxide following reagents to a 50 ml one-mark volumetric
O
(DANGER: << C >>I. flask:
10 ml of eluent (4.4.4)
4.4.9 Sulfuric acid, c(H2S04) = 0,5 mol/l
This solution can be prepared from sulfuric acid 1 ml of formalin (4.4.7) (< B > < C > < S >)
(1,84 g/ml approx.) (DANGER: << C >>I.
3 ml of pH 2,8 formate buffer (4.4.3)
4.5 Apparatus and glassware
5,O ml of potassium iodate solution (4.4.1)
4.5.1 Apparatus
5 ml of cadmium iodide-amylose reagent (4.4.5)
4.5.1 .I Transmission spectrometer, suitable for
5 ml of pH 2,0 formate buffer (4.4.2)
recording optical absorbance over the wavelength
range of interest, and a 5 cm cell.
Swirl to mix, and make up to the mark with water.
Stopper the flask and mix thoroughly. After 3 min,
4.5.1.2 pH meter (see also clause 3). measure this solution as described in 4.8.3 and
4.8.4.
4.5.1.3 Interval timer
4.7 Preparation of test sample
4.5.1.4 Dropping pipettes (also known as medicine
O
droppers) (as required).
Analyse samples within 2 weeks of photographic
processing.
4.5.1.5 Buchner funnel
4.7.1 Cut a 10 cm2 strip of paper or film, obtained
4.5.1.6 Filter paper, 11,O cm diameter; ashless; fine from a non-image area or an area of minimum density.
porosity (2,5 pm particle retention); slow flow (240 s Fold the strip into a “W“ with the emulsion side in-
for 1 O0 ml prefiltered water); smooth surface; wards. Place the folded sample in a dry 30 mI beaker.
dense’).
4.7.2 Add 10 ml of eluent (4.4.4) to the beaker. Swirl
the beaker until the sample is completely immersed.
4.5.2 Glassware (see also 3.3)
Swirl again after 1 min and 5 min. Total elution time
shall be 10 min for resin-coated (RC) paper, light-
All glassware shall be free from reducing or oxidizing
weight paper and single-weight paper. For medium-
materials. One way to assure this is to rinse the
5) A diatomaceous earth such as Aldrich Chemical Company No. 16,743-6, or BDH 33134-2K are examples of suitable ma-
terials. This information is given for the convenience of users of this International Standard and does not constitute an
endorsement by IS0 of these products.
6) Commercially available analysed reagent solutions are recommended. Annex D provides a procedure for the preparation
of standard sodium thiosulfate solution using sodium thiosulfate pentahydrate (NazSz0,~5HzO).
7) Whatmans No. 42 filter paper is an example of a suitable product available commercially. This information is given for the
convenience of users of this International Standard and does not constitue an endorsement by IS0 of this product.
4
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IS0 417:1993(E)
weight or double-weight paper, the contact time with Low levels of thiosulfate (0,001 g/m2 to 0,009 g/m2)
the eluent shall be increased to 20 min. are generally achieved only in well-washed, fine-grain,
black-and-white films.*)
4.7.3 Add 1 ml of formalin (4.4.7)
() to the beaker. Swirl, making sure
that the solution reaches any droplets on the beaker 4.9 Calibration, including blank
wall. Allow a reaction time of 1 min.
4.9.1 Prepare a stock sodium thiosulfate solution
(0,001 O mol/i) by pipetting 1,00 ml of 0,100 O mol/l
4.7.4 Add 3 ml of pH 2,8 formate buffer (4.4.3).
sodium thiosulfate (4.4.6) into a 100 ml one-mark
Swirl to reach any droplets on the beaker wall and al-
volumetric flask. Make up to the mark with water.
low 2 min for completion of the reaction. During these
2 min, pipette 5,O ml of potassium iodate solution
(4.4.1) into a 50 ml volumetric flask. Add 5 ml of cad-
4.9.2 Assuming a 10 cm2 sample, pipette the vol-
mium iodide-amylose reagent (4.4.5) to the volumetric
umes of stock solution given in table1 into approprl-
flask and swirl the flask. Add 5 ml of pH 2,O formate
ately labelled 30 ml beakers.
buffer (4.4.2) to the volumetric flask and swirl the
flask.
Table 1 - Preparation of samples for calibration
Equivalent ps
4.8 Colorimetric measurement Volume of stock solution
PI g/m2 CIg/cm2
4.8.1 Set a timer for 3 min.
50 0,005 6 0,56
1 O0 0,011 1 ,I
4.8.2 Transfer the liquid from the 30 ml beaker
300 0,034 3,4
(4.7.4) to the 50 mI volumetric flask containing the
None Blank Blank
iodine-amylose solution (4.7.4). Rinse the sample and
beaker with 10 mI of water and transfer the rinsings
to the 50 ml volumetric flask containing the reagent
4.9.3 Extract the samples according to 4.7.2 by
mixture (4.7.4). Make up to the mark with water and
(4.4.4) and continuing the procedure
adding the eluent
mix well.
steps up to and including 4.8.3. The sample sizes
given in 4.7.1 are replaced by the pipetted quantities
4.8.3 After 3 min from the time of transfer, measure
given in 4.9.2. If the sample has a gelatin coating on
the absorbance of the solution at 610 nm in a 5 cm
each side of the base, it may contain twice the level
glass cell versus air using the spectrometer (4.5.1 .I 1.
of thiosulfate ions as a sample coated on one side
only.
4.8.4 Convert the absorbance obtained into the
level, ps, of thiosulfate ions (S20g-), in grams per
4.9.4 Plot AA against ps, in grams per square metre
square metre, from an appropriate calibration curve
(for a cm2 sample).
where
5 Methylene blue method
AA is the absorbance difference;
5.1 Use
Ab is the absorbance of the blank solution;
This method determines only thiosulfate. Procedyres
A, is the absorbance of the test solution.
are spe$fied to cozer the range 0,001 g/m to
0,45 g/m (0,l pg/cm to 45 pg/cm ) of thiosulfate for
If falls below 0,090, then re-extract the sample u-
fibre-based paper, film or plates.
1 smaller sample. Correct the result then obtained
in<
from the calibration curve as follows:
5.2 Selection of the methylene blue method
ps = 10 x pc/S
to cover the proper range
where
The methylene blue method consists of two separate
procedures that permit a broad range of concentration
pc is the level of S203- ions read from the cali-
to be covered. The rangezfor Procedu;e I (5.7) is froy
bration curve, in grams per square metre;
0,001 g/m2 to 0,009 g/m (O,I pg/cm to 0,9 pg/cm
S is the sample area, in square centimetres. of thiosulfate and Procedure II (5.8) covers the range
8) 1 pg/cm2 = IO-' g/m2
5
IO
---------------------- Page: 8 ----------------------
IS0 417:1993(E)
from 0,0209 g/cm2 to 0,45 g/m2 (0,9 pg/cm2 to
5.5 Reagents
45 pg/cm ) of thiosulfate. In both procedures, the
sample sizes and the volumes of the test solutions
5.5.1 Eluent
are such that no more than 0,Ol g (IO pg) of
thiosulfate is present. That ensures using only a
Dissolve 1,0 g f 0,l g of potassium iodide (KI),
straight-line calibration curve. The range covered for
20,O g f 0,l g of potassium bromide (KBr) and
Procedure II was expanded by using a larger volume
1,0 g f 0,l g of potassium dihydrogen phosphate
of eluent. An alternative, but less preferable, method
(KH2P04) in 1 litre of water. This reagent is stable for
of expanding the range is to use a smaller sample
at least 8 months.
size. However, due caution shall be exercised to en-
sure a representative sample.
5.5.2 Borohydride reagent
Dissolve 3,O g of fresh potassium borohydridegilo1
(KBH,) (DANGER: < C > < B > < F >) in 100 ml of
5.3 Principle sodium hydroxide solution (5.5.6). This reagent is sta-
ble for 1 week in a cool place. Package solutions to
be used beyond 1 week in small individual bottles
Residual thiosulfate that is extracted (eluted) from the
which, once opened, are discarded at the end of the
sample is reduced by potassium borohydride to SUI-
day.
fide. The sulfide reacts with oxidized N,N-dimethyl-
p-phenylenediamine (DP) to form methylene blue
(MB). The absorbance of the blue colour is measured
5.5.3 Acetone
with a photometer or spectrometer. The thiosulfate
level is determined from a calibration curve. A curve
is to be prepared in each laboratory to eliminate errors
5.5.4 Ferric sulfate reagent
due to variations in the reagents, equipment or tech-
nique, but it should approximate to the curve in
To 89 ml of water in a beaker, carefully add, with
figure 1.
stirring, 15 ml of sulfuric acid (1,84 g/ml approx.)
(DANGER: << C >>). Dissolve 3,OO g f O, 1 O g of hy-
NOTE 8 The curve shown in figure 1 is only an example
drated ferric sulfate [Fe2(S04)pH20] (n is approxi-
and is not to be used as a working calibration curve. A
mately 9) in the diluted acid. This reagent is stable for
working calibration curve is to be established only by fol-
at least 8 months.
lowing the procedures described in this International Stan-
dard.
5.5.5 NND Reagent
To 89 ml of water in a beaker, carefully add, with
stirring, 15 ml of sulfuric acid (1,84 g/ml approx.)
5.4 Chemical reactions
(<< C >>). Dissolve 1 ,O0 g f 0,Ol g of NNdimethyl-
p-phenylenediamine sulfate in the diluted acid. Add
The following reactions occur: 5 g of powdered activated carbon or a filter aid such
as Florisil@lll (100 - 200 mesh) and stir the mixture for
3i-i2û + 2S20:- + BH4 -, about 1 h to 2 h. Allow the absorbant to settle and
filter the supernatant solution using prefolded
HS-+ 2HS03 + H2B03 + 2H2 medium-porosity filter paper (5.6.5)12'. If the solution
is pink, repeat the decolourization process. This re-
H2S + 6Fe2(S0& + 2DP -, MB agent is stable for at least 8 months.
9) DANGER: Potassium borohydride is hazardous in the following ways.
a) Personnel: Potassium borohydride is flammable and corrosive. It liberates hydrogen gas when in contact with water or acid
and poisonous gases in the presence of acid. In concentrated form, it causes severe skin burns. Handle with extreme care
and store in a bottle with a loose stopper.
b) Sensitized materials: Potassium borohydride is a powerful fogging agent. Avoid contamination of unprocessed film, paper
and processing solutions. Thoroughly wash hands and equipment after the use of solid borohydride or borohydride reagent.
1 O) Also known as potassium tetrahydroborate.
11) FlorisiP is an example of a suitable product available commercially. This information is given for the convenience of users
of this International Standard and does not consitute an endorsement by IS0 of this product.
12) Whatman@ No. 2V filter paper is an example of a suitable product available commercially. This information is given for the
convenience of users of this International Standard and does not constitute an endorsement by IS0 of this product.
6
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IS0 417:1993(E)
5.5.6 Sodium hydroxide solution, c(Na0H) = 0,20
5.7.1.2 Plates
mol/l (8,O g/I)l3)
Take sayples from an area of minimum density. Cut
a 10 cm sample and place it, photographic layer up,
5.6 Apparatus and glassware (see also
a glass or plastic tray that is only slightly larger than
in
clause 3 )
the plate. Add 5,O ml of eluent (5.5.1) and allow
10 min for elution, accompanied by a gentle rocking
See 4.5.2 for details of the cleaning of glassware.
action. Transfer as much of the eluent as possible into
a sample vial (5.6.1). Continue according to the pro-
5.6.1 Sample vials, of 11 ml capacity, with
cedure given in 5.7.1.3.
polyethylene caps; four are required.
NOTE 10 If destruction of the plate is undesirable, im-
merse the entire plate in a tray slightly larger (0,5 cm on
5.6.2 Glass or plastic trays, for plates.
each side) than the plate and elute as above, but use a
larger volume of eluent (5.5.1 1, keeping the proportion of
The trays shall be only slightly larger than the plates,
eluent to plate area constant. After elution, place 5 ml of the
for elution.
resulting test solution into a sample vial (5.6.1). Continue
the procedure given in 5.7.1.3. Save the remainder of the
5.6.3 Dropping pipettes, four are required.
test solution for possible use in step 5.8.1.1. If it is to be
used, dilute it five-fold. Wash the plate after testing, to re-
move residual eluent.
5.6.4 Visible photometer or spectrometer, with
1 cm cells.
5.6.5 Filter paper, prefolded, medium porosity
(8 pm particle retention); mediym flow (55 s for 5.7.1.3 Film and plates
100 ml prefiltered water) (15 cm folded paper).12)
Fill four dropping pipettes in readiness with the fol-
lowing four reagents:
5.7 Procedure I: Low levels of thiosulfate
ions, 0,001 g/m2 to 0,009 g/m2 (0,l pg/cm2 to
borohydride reagent (5.5.2)
03 pg/cm2)
acetone (5.5.3)
NOTE 9 This level of S203- is generally attained in only
well-washed, fine-grain, black-and-white film, RC paper and
plates. For higher levels, such as in many colour products, ferric sulfate reagent (5.5.4)
use Procedure II (see 5.8) or the silver densitometric
method (see clause 6). If the sample has gelatin backing,
NND reagent (5.5.5)
the backing layer may contain as much thiosulfate as the
emulsion layer. The test method measures the total
After addition of the borohydride reagent, complete
thiosulfate. Fibre-based paper is not included in this pro-
the following additions within 15 s:
cedure because this paper usually contains higher levels of
s20;-.
a) add 5 drops of the borohydride reagent (5.5.2);
swirl to mix;
5.7.1 Preparation of test sample
b) add 10 drops of acetone (5.5.3); swirl to mix;
Analyse samples within 2 weeks of photographic
processing.
c) add 5 drops of the ferric sulfate reagent (5.5.4) and
5 drops of NND reagent (5.5.5).
5.7.1.1 Film
Cap immediately. Hold cap on firmly and shake the
Obtain a 10 cm2 sample (for example, 6,25 cm vial vigorously for 30 s, being careful that the top of
x 16 mm withou
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