HunterLab SpectraTrend HT, Руководство пользователя

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SpectraTrend HT User’s Guide 3.2
107
Fastness - Part A03: Grey Scale for Assessing Staining, or AATCC Evaluation Procedure 2, “Gray Scale for
Staining,” and is used to assess the degree of staining of adjacent fabrics in a color fastness test.
2 2
GS
* dL - * dE 0.4 - * dE dE
=
Use dE
GS
to calculate the GSS as follows:
GSS = 6.1 - 1.45 ln (dE
GS
) for Ratings 1 to 4.
If the GSS calculated by the above equation is greater than 4, recalculate using the following equation:
GSS = 5 - 0.23dE
GS
for Ratings 4 to 5.
Metamerism Index
In order to display metamerism index, two data views must be configured in your product setup that
contain different illuminant/observer combinations.
The Metamerism Index is designed to indicate the degree to which two items which match under one
illuminant no longer match under a second illuminant. The formula for deriving the index is:
( ) ( ) ( )
2
n2 n1
2
n2 n1
2
n2 n1
b - b a - a L - L MI d d d d d d
+ + =
where n1 is the original illuminant and n2 is the illuminant selected in the product setup using the
Duplicate standard type.
Shade Number
The shade number, SSN, that can be obtained using your ColorFlex EZ provides a convenient way of
sorting samples into groups (or “blocks”) of similar color. This is helpful in situations where several
separate pieces will be combined into a whole and the colors of the pieces must be closely matched.
In order to use shade sorting, you must first read an ideal product standard into your setup preferably as
a PHYSICAL standard, and your first data view must be displaying the L*a*b*, L, a, b, or dLdCdH color
scale. Then enter your desired tolerances into the setup as well. These tolerances will provide the
borders on which your shade number blocks will be based. CMC autotolerancing may be used to
calculate these tolerances if desired, but manually-entered rectangular tolerances work just as well.
Then, on the CMC/Shade Sort screen, enter the number of shade blocks you wish to have fit inside your
tolerance borders. Choices available are 1, 3, 5, 7, and 9. There are nine shade blocks within the
acceptable limits (able to be displayed) for each dimension (L*a*b*), so there are 729 possible shade
number assignments. Any sample that falls outside the displayable limits is indicated not with numbers,
but with a + or -, depending on whether the actual shade number should be higher than 9 or lower than
1.