IS 6155 : 2024/ISO 424 : 1994 Sodium Carbonate, Anhydrous and Monohydrate, Photographic Grade - Specification
(Superseding IS 12121 : 1987)
NATIONAL FOREWORD
This Indian Standard (Second Revision), which is identical to ISO 424 : 1994 'Photography - Processing chemicals - Specifications for anhydrous sodium carbonate and sodium carbonate monohydrate' issued by the International Organization for Standardization (ISO), was adopted by the Bureau of Indian Standards, on the recommendation of the Electroplating Chemicals and Photographic Materials Sectional Committee and approval of the Chemical Division Council.
IS 6155 was first published in 1971 and was revised in 1987 under the title 'Specification for sodium carbonate, monohydrate, photographic grade'. Sodium carbonate, monohydrate is used in the processing of sensitized photographic materials. It finds use in preparing photographic developers, particularly in colour films where high purity of the ingredients is very essential and extremely important. It has a chemical formula Na2CO3.H2O and molecular mass 124. In the first revision, the material suitable for only photographic industry was covered and the requirement for assay was modified. Also, the requirements for free alkali, bicarbonate and reaction to ammonical silver nitrate were added.
The requirements of Sodium Carbonate, Anhydrous, Photographic Grade was specified in another separate standard namely IS 12121 : 1987 'Specification for Sodium Carbonate, Anhydrous, Photographic Grade'. Sodium carbonate, anhydrous is used in the processing of sensitized photographic materials. It has the chemical formula Na2CO3 andmolecular mass 106.
The Committee responsible for formulation of these standards decided to further revise IS 6155 by adopting ISO 424 : 1994 on dual number basis. This revision is being brought out by amalgamating IS 6155 and IS 12121 and will be published as second revision of IS 6155 and subsequent to this publication IS 12121 will be superseded.
ISO 424 : 1994 specifies the requirements for two grades of sodium carbonate; namely anhydrous and monohydrate. Accordingly, the title of the standard is being modified to 'Sodium carbonate, anhydrous and monohydrate, photographic grade - Specification'.
The text of ISO standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:
a) Wherever the words 'International Standard' appears referring to this standard, they should be read as 'Indian Standard'; and
b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.