With our Visible Light Reflectance Test service, we may use any number of color coordinate systems, the primary being the CIE L*a*b* system.
The L * value indicates the Level of Light- Dark. (0 – 100)
the a* value Redness or Greenness (-100 = Green; +1-00 = Red)
the b* value Yellowness or Blueness (-100) = Blue; +100 = Yellow)
The two measures calculated are:
1) DELTA E which is obtained by the formula
√((L*-L*)² + (a*-a*0)² +(b*-b*0)²) (1)
The Delta E value merges the overall color change into a parameter that provides a single overall value of change from the baseline.
Where L*, a* and b* are the CIE colorimetric parameters such that the L * value indicates the Level of Light- Dark, the a* value Redness or Greenness, and the b* value Yellowness or Blueness.
The delta E is always positive (or zero) and a value less than 2.0 is generally considered as a change
of color that is less than what the human eye can distinguish.
2) The Yellowness Index YE313 (per ASTM E313)
The Yellowness Index (ASTM E313) characterizes the amount of “Yellowing,” on a scale of -100 (saturated blue to +100 saturated yellow.
To send Materials and Equipment to Solar Light Company for Testing:
1. Complete the necessary form and mark box “Attn: Materials Testing Laboratory”.
2. Issue a purchase order or include payment information.
3. Provide specific shipping instructions for the return shipment if applicable, and email PO with Return Form to Solar Light Company
4. Enclose a copy of the completed form in the package with the sample(s).
Ship prepaid via UPS or FedEx, fully insured to:
Solar Light Company, LLC
Attn: Materials Testing Laboratory
100 East Glenside Avenue
Glenside, PA. 19038 USA
Test and Measurement Equipment
Solar Light Model 16S-150-003 Short Arc Xenon UV Solar Simulators
Solar Light Model 16S-300-003 Short Arc Xenon UV Solar Simulators
UVA Fluorescent lamps
UVA+B Fluorescent lamps
UVC Fluorescent lamps
High Intensity Visible Fluorescent lamps
Solar Light Model LS-1000 6″ Air Mass
Solar Light Model LS-1000 6″ UV Solar Simulator
Solar Light Model PMA2100 dual channel data-logging radiometer
Solar Light Model PMA2107 UVA+B Sensors
Solar Light Model PMA2110 UVA Sensors
Solar Light Model PMA2144 Class II Pyranometer
X-rite Color Eye 7000A Spectrophotometer
Optronic Laboratories Model 750 Double Grating Monochromator System
Optronic Laboratories Model 740 A/D Double Grating Monochromator
Optronic Laboratories Model 730A Radiometer
Optronic Laboratories Model 740-1C Controller
Optronic Laboratories Model OL 220M Quartz-halogen lamp
Optronic Laboratories Model 65DS Precision Current Source
Solar Light 290SPF UV Transmission Analyzer
Controlled Environmental Test Equipment
Stability Environments Controlled Temperature, Humidity & Light Walk-in Chamber
Stability Environments 33 cu ft Controlled Temperature & Humidity Reach-in Chamber
Tenny Environmental Chamber