Carpets are produced in batches - know as creels - and usually each batch produces 500m2 - 3000m2 in a single width, Depending on the creel size. Whilst the recipe used by the byer remains constant, and is followed to the letter, in each seprate production the colour reproduction will vary from batch to batch. However production is matched back to the original or master smaple to ensure the that colour remains "within a commercial tolerance"
This process of not an excat science and a commercial tolerance is subjective but nertheless is useally the professional judgement of the head dyer based on his/her experince.
A Greather level of tolorance is required on blended colours (heathers etc). To ensure perfect colour matching it is advisable that a single width be used in any installation requiring exact colour matching.
N.B Carpets which are laid with the pile travelling in different directions, even though they be from the same batch will appear not to match, For further information please check with the manufacturers recommendations.
Occasionally an odd tuft or two can work it way to the surface and stand proud of the rest of the pile. This probably due to the one end of the tuft being longer then the other i.3 J shaped tuft instead of V shaped. Remedial action merely requires that the offending tufts be scissor trimmed level with the rest of the pile. They should never be pulled out.
Fading on Wool
Carpets made from wool can and do fade in use. The degree of fade can vary depending on the colour chosen and the local conditions to which the carpet is subjected.
Fading can be caused by exposure to ultra violet light which is found in daylight, but is acceletated when sunlight shines direclty onto the carpet. This has the effect of lighting or "Bleaching" the colour just as animal hair.
Protection should be given to carpets exposed to such conditions just as you would protect other furiture or fabrics
A complaint on fading would be considered jusified if it failed to meet the required shade standard when tested to the British Standard BS1006 (1990).