James Heal Blue Wools are made in Germany and originate from DEK – The German Colour Fastness Commission. DEK hold the global master standards.
Every batch of Blue Wools 1-7 is rigorously tested for conformance against ISO 105 - B08.
These tests are:
- Instrumented assessment of evenness of the dye
- Instrumented and visual assessment of the fading characteristics
Blue Wool 8 is not suitable to be tested in this way as the time taken to fade to a grade 3 and 4 would be too great and not time effective.
A more efficient method for Blue Wool 8 is currently being devised.
A PDF version of this FAQ is available for reference.