International Standard
ISO 787-4:1981
General methods of test for pigments and extenders — Part 4: Determination of acidity or alkalinity of the aqueous extract
Reference number
ISO 787-4:1981
Edition 1
International Standard
Read sample
ISO 787-4:1981
Published (Edition 1, 1981)
This standard was last reviewed and confirmed in 2019. Therefore this version remains current.

ISO 787-4:1981

ISO 787-4:1981
CHF 42
Convert Swiss francs (CHF) to your currency


The principle of the method consists in the hot extraction of the material by following the procedure specified in ISO 787/3, to the stage of obtaining a perfectly clear filtrate. The determination is carried out with indicator solution (method A). If the solution with the methyl red indicator is yellow (alkaline), titrate it with the hydrochloric acid solution to an orange end-point; if the solution with the methyl red indicator is red (acid), titrate it with the sodium or potassium hydroxide solution to an orange end-point. The other method (method B) is the potentiometric determination. Take 100 ml of the test solution, insert the electrodes of the pH measuring device and read the pH value.

General information

  •  : Published
     : 1981-09
    : International Standard under systematic review [90.20]
  •  : 1
     : 2
  • ISO/TC 256
  • RSS updates

Life cycle

Got a question?

Check out our Help and Support

Check out our FAQs

Customer care
+41 22 749 08 88

Opening hours:
Monday to Friday - 09:00-12:00, 14:00-17:00 (UTC+1)