Grey Scales

What are the differences between the ISO / AATCC and the M&S assessment mask?

James Heal supplies assessment masks for the following methods: - ISO / AATCC  (766-477) - M&S (766-478)

There are similarities between the 2 masks:

  • Size - 228mm long and 58mm wide
  • Viewing windows - 32mm x 28mm and 15mm x 50mm
  • Matt black on both sides

There are 2 physical differences between the masks:

  • ISO / AATCC is 0.8mm thick and is made from a single layer of flexible plastic
  • M & S is 1.9mm thick and is laminated

The main differences are how these masks should be used.


The 32mm x 28mm mask is used for assessing crocking cloth staining, or when a larger area is needed.

The 15mm x 50mm mask is used for assessing both staining and change in colour.


The 32mm x 28mm mask is for assessing change in colour.

The 15mm x 50mm mask is for assessing level of staining.

The size of the window allows for isolated from the surrounding fabric.