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:

Name Ref No. BWS Rating
Almond 1004 / 3004 3
Antique White 975 / 3975 5
Aqua 3993 5+
Arctic White 889 / 389 5
Bamboo 1007 / 3007 5
Barley 989 / 3989 5
Beaujolais 849 / 349 4
Beige 810 / 310 3
Black 872 / 372 4
Blossom 805 / 305 3
Bluebell 840 / 340 4
Bottle Green 832 / 332 4
Bronze CM18 5+
Buff 803 / 303 3
Burgundy 853 / 353 4
Buttermilk 1003 / 3003 4
Cameo 984 / 3984 3
Chalk White 1001 / 3001 4
Champagne 807 / 307 4
Charcoal 825 / 325 4
Chestnut 720 / 3720 3
China Red 1040 / 3040 4
Chive 931 / 3931 4
Chocolate 813 / 313 4
Clear Water 951 / 3951 5
Cloud 845 / 345 5
Cobalt Blue 842 / 342 4
Coffee 811 / 311 3
Copper CM17 4
Cinder Grey 3998 4
Cream 802 / 302 4
Cream Ingres 986 / 3986 4
Dawn Mist 877 / 377 4
Dove Grey 822 / 322 3
Dusty Pink 855 / 355 4
Ebony 3999 4
Eggshell 701 / 3701 3
Emerald 3991 4
Essence White 917 / 3917 4
Falcon 507 / 3507 3
Forest Green 1031 / 3031 4
Geranium 3997 4
Gold 862 / 362 5
Granite 828 / 328 4
Grape 890 / 390 4
Green Gold CM13 5+
Harvest Beige 920 / 3920 2
Haystack 965 / 3965 3-4
Hazelnut 859 / 359 4
Holly Green 833 / 333 4
Honeysuckle 982 / 3982 4
Iced Crystal 885 / 385 3
Iced White 973 / 3973 4
Ivory 801 / 301 4
Laurel 835 / 335 4
Leaf Green 1030 / 3030 4
Lemon 3995 5
Lime 3992 5
Loganberry 715 / 3715 4
Lupin 846 / 346 4
Maple 834 / 334 3
Midnight 839 / 339 4
Moorland Green 831 / 331 4
Mushroom 1023 / 3023 4
Nightshade 954 / 3954 4
Off White 981 / 3981 4
Old Gold 864 / 364 5
Old Ivory 809 / 309 3
Or 506 / 3506 3
Osprey 725 / 3725 3
Oxford Blue 843 / 343 4
Oyster 808 / 308 4
Pale Gold CM14 5+
Pale Silver CM12 5+
Pastel Blue 844 / 344 4
Pastel Green 829 / 329 4
Pastel Pink 856 / 356 4
Pearl 800 / 300 4
Pigeon 945 / 3945 3
Platinum CM19 4-5
Polar White 1002 / 3002 4
Poppy 851 / 351 4
Porcelain 847 / 347 4
Portland 821 / 821 5
Putty 983 / 3983 4
Rose Gold CM16 5+
Rouge 850 / 350 4
Sage Green 830 / 330 3
Sand 804 / 304 4
Sand Ingres 985 / 3985 4
Sandstone 925 / 3925 4
School Grey 826 / 326 4
Seal Brown 815 / 315 4
Sepia 814 / 314 3
Shamrock 3990 4
Silver 861 / 361 5
Silver Birch 710 / 3710 3
Simply White 891 / 391 3-4
Sky 3994 5
Slate 841 / 341 4
Smoke Grey 824 / 324 5
Snow White 971 / 3971 3
Soft White 875 / 375 5
Solar Gold CM15 5+
Spice Brown 916 / 3916 4
Stone 823 / 323 4
Sugared Almond 882 / 382 3
Tangerine 3996 4
Unicorn 501 / 3501 3
Vanilla 1015 / 3015 4
Warm Ivory 806 / 306 4
White 871 / 371 3
White Gold CM11 5
White Ingres 987 / 3987 4