Blue Wool Scale for Colourmount Boards

The Blue Wool Scale (BWS) indicated the lightfastness of colourants. Lightfastness is the chemical stability of a pigment or dye under long exposure to light.

A rating of between 0 and 8 is awarded. 0 denotes extremely poor lightfastness, whilst 8 denotes excellent lightfastness.

Each Colourmount board has its individual BWS rating marked on the reverse. A list of the BWS ratings for each Colourmount board is shown below:

Blue Wool Test
Name BWS Rating
Almond 3
Antique White 5
Arctic White 5
Bamboo 5
Barley 4
Beaujolais  4
Beige 3
Black 4
Blossom 3
Bluebell 4
Bottle Green 4
Buff 3
Burgundy 4
 Buttermilk 4
 Cameo 3
 Chalk White 4
 Champagne 4
 Charcoal 4
 Chestnut 3
 China Red 4
 Chive 4
 Chocolate 4
Clearwater 5
Cloud 5
Cobalt Blue 4
Coffee 3
Cream 4
Cream Ingres 4
Dawn Mist 4
Dove Grey 3
Dusty Pink 4
Eggshell 3
Essence White 4
Falcon 3
Forest Green 4
Gold 1
Granite 4
Grape 4
Harvest Beige 2
Hazelnut  4
Holly Green 4
Honeysuckle 4
Iced Crystal 3
Iced White 4
Ivory 4
Laurel 4
Leaf Green 4
Loganberry 4
Lupin 4
Maple 3
Midnight 4
Moorland Green 4
Mushroom 4
Nightshade 4
Off White 4
Old Gold 1
Old Ivory 3
Or 3
Osprey 3
Oxford Blue 4
Oyster 4
Pale Peach 4
Pastel Blue 4
Pastel Green 4
Pastel Pink 4
Pearl 4
Pigeon 3
Polar White 4
Poppy 4
Porcelain 4
Portland 5
Putty 4
Rose 4
Rouge 4
Sage Green 3
Sand 4
Sand Ingres 4
Sandstone 4
School Grey 4
Sea Spray 4
Seal Brown 4
Sepia 3
Silver 1
Silver Birch 3
Slate 4
Smoke Grey 5
Snow White 3
Soft White 5
Spice Brown 4
Stone 4
Sugared Almond 3
Unicorn 3
Vanilla 4
Warm Ivory 4
White 3
White Ingres 4