4.1 This test method gives the amount of ash remaining in the specimen after water extraction to remove water solubles from the leather in accordance with Test Method D2876. The insoluble ash is used in calculating the combined tannin because it is part of the tanned fiber structure that does not leach from the leather during water extraction.

1.1 This test method covers the determination of the insoluble ash in all types of vegetable-tanned leathers. This test method does not apply to wet blue.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.