The approach to grading has been based on some basic metrics used by other suppliers.  Given the uniqueness of the collections Grains per inch (GPI) and degree of quarter have been used to help differentiate as follows:

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Master: Even growth rings of at least 20 GPI, perfect quarter, uniform colour or uniform colouration pattern.

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3A: Even growth rings of at least 15 GPI, perfect quarter, uniform colour or uniform colouration pattern.

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2A: An average of 12 GPI within the template area, within 10 degrees of quarter, very little colour or coloration pattern variation.

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1A: An average of 8 GPI within template area and within 15 degrees of quarter, minor colour or colouration pattern variation.

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Sub-1A: An average of 8 GPI within the template area, within 20 degrees of quarter, some colour or colouration pattern variation.

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B-sets: Sub-1A criteria but with minor cosmetic flaws within the template area.   

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Note that some gradings may be annotated with a '+' or a '-' which reflects that the set in question falls within two of the grading criteria stated above (ie. Grading of 1A+ denotes an average of 8 GPI and within 10 degrees of quarter).

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