TAPPI T 444
Silver tarnishing by paper and paperboard
|Publication Date:||1 January 2012|
This method is for identifying papers and boards that will tarnish or stain silver. The appearance of the tarnish or stain of silver by a test specimen of the sample is reported, together with the distribution of the tarnishing or staining. Reducible sulfur activity is a common cause of tarnishing.
Certain sample types, such as water repellent or metal-coated papers, or board may require a modification of the test procedure. In most cases, water repellant or metal-coated samples may be tested without wetting the test specimen and by prolonging the time in contact with the silver to at least 24 h. When such sample types are tested, state any modification of the procedure which is used in the report.
The principles involved in this test method might be used to test samples for their staining or corrosion properties with respect to other metals, such as steel, copper, nickel, brass, etc. In such cases, it is necessary to use plates or forms of the particular metal or alloy in question and to make such modifications as may be required for the particular purpose. For example, in the case of metal that would rust, the paper might not be wetted; it could instead be heated in an atmosphere of high humidity.
Specific details of testing for tarnishing or staining papers are beyond the scope of this test method. The information in 10.2 and 10.3 is given only as examples of extensions of the test method which may be possible.