HunterLab EasyMatch QC, User Manual

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EasyMatch QC User’s Manual Version 2.1
Lessons 2-15
Lesson 4: Using a Hitch Standard
Hitch standardization can be used to make your instrument read samples of a particular color the same
way as another instrument, improving agreement. If a product standard has been measured on another
instrument and color or spectral values have been assigned to it, then your instrument can be adjusted to
those values so that samples you read are corrected for any differences between the two instruments.
To perform a hitch standardization you need a standard with either color values or spectral values
assigned to it. Your instrument should already be attached to the computer and installed in EasyMatch
QC before performing this lesson.
1. Standardize the instrument in the same mode in which the hitch standard’s color values were
obtained. In this example we’ll use RSIN (reflectance) mode.
2. Place the standard at the measurement port and measure it by choosing Read Standard from the
Measurements menu. For this example, read your instrument white tile.
3. Select (check) Job Tree in the View menu if it is not already displayed.
4. Right click on the standard you just read in the Job Tree and select Properties from the menu that
appears.
5. Click on the Hitch button. The Hitch Readings to Standard screen appears.
6. Select whether the assigned values are spectral or tristimulus (color values). We happen to have
tristimulus values.
7. Choose whether you wish to use a ratio or additive hitch. For this lesson, choose Additive.
An additive hitch is a simple linear offset from the values measured using your instrument. The
value displayed in the Color Data Table for each parameter (such as L, a, and b) is the measured
value plus the offset value indicated by the hitch standard. The offset value may be positive or
negative and is automatically calculated by EasyMatch QC. When performing an additive hitch, the
hitch standard should be very close in color to the samples you wish to measure using the hitch. For
example, a reddish-orange standard should be used when measuring tomato products.