Measuring Lip Balm
The instrument illustrated below is a ColorQuest XE. Measurements on an UltraScan VIS would be carried out in a very similar fashion.
Lot-to-lot or piece-to-piece color consistency is an important indicator of quality for many colored items. Small tubes of cosmetics such as lip balm can be easily measured at the reflectance port of a benchtop sphere instrument such as the ColorQuest XE.
A HunterLab ColorQuest XE Diffuse/8° spectrophotometer can be used to measure the reflectance of tubes of lip balm carefully positioned over a special handling device. The small area view (SAV) option must be available with the instrument in order to use this measurement method.
The ColorQuest XE
The Application
Lip balm has several non-uniform characteristics that require compensating preparation and presentation techniques in order to ensure a repeatable sample measurement.
The available measurement area may be very small and/or curved. The proper size port insert must be used to limit the area measured by the instrument, and a flat area must be located for measurement.
The sample is a soft solid that could soil the instrument's sphere. The samples must be measured through the clear window of a special port plate in order to be effectively made into a solid and to protect the sphere.
Lip balm is translucent — not opaque — and will be sensitive to ambient light and to small differences in the optical configuration of the instrument. Using a sufficient sample thickness and/or constant background will minimize these effects.
Note: If inter-instrument agreement is a concern when measuring lip balm, all the instruments used for those measurements MUST be the same model to minimize measurement differences.
| Recommended Color Scale | CIE L*a*b* or Hunter L, a, b as a full color descriptor |
| Recommended Illuminant/Observer | D65/10°. C/2° may also be used. |
Measurement Method
| 1. Configure your software or the touch screen applet to read using the desired color scale, illuminant, and observer. | |
| 2. Install the modified port plate that is provided with the CMR 2790 lip balm holder (HunterLab Part Number CMR-2790) and standardize the instrument in RSEX mode for the small area of view in order to negate the effect of the glass covering the port plate. First standardize on the light trap, then the white tile. |  |
| 3. Install the lip balm holder to the modified port plate as described in your documentation for CMR 2790. |  |
| 4. Remove the cap from the lip balm stick and advance the balm at least 1/4 inch above the lip of the tube. |  |
| 5. Insert the open end of the lip balm tube into the tube holder until the balm is flush against the port plate glass. Use a finger to maintain a slight pressure on the tube. |  |
| 6. Take a single color reading of the sample. Turn the tube clockwise 90° or insert another tube of the same color and read it at least once more. Average the multiple color readings for a single color measurement. Averaging multiple readings with rotation or movement between readings allows you to better estimate the color of the sample as a whole. | |
| 7. Record the average color values. |