710s Index Calculation
Shows how the CI-710s with current firmware calculates indexes internally
This article describes how the CI-710s indexes are being calculated by the instrument
Date: 10-10-2022
As long as the instrument has the newest firmware version (v0.9.38), the calculations are done internally with the instrument.
For example from the below spreadsheet (CRI index) CRI1 = (1/ R510 ) - (1/ R550 ) At 549.60nm the reflectance measurement is 5.12749917571458 At 550.19nm the reflectance measurement is 5.11071477484723 ( 5.12749917571458 + 5.11071477484723 ) / 2 = 5.119106975 Average At 509.79nm the reflectance measurement is 2.12485455219971 At 510.38nm the reflectance measurement is 2.23117249434557 (2.12485455219971 + 2.23117249434557) / 2 = 2.1780135232726 Average CRI = (1/ 2.1780135232726 ) - (1/ 5.119106975 ) CRI = 0.459133 - 0.195346572 CRI = 0.263786428
Calculation based on Spectravue (Calculation file): CRI1,(1/R510) - (1/R550), 0.238664841795298
Calculation manually based on measurements: 549.60 550.19 509.79 510.38 549.601 550.194 509.788 510.383 Absorbance 1.230007199 1.232308513 1.64434836 1.631325068 1.230007199 1.232308513 1.644348360 1.631325068 Abs Reflectance 5.127499176 5.110714775 2.124854552 2.231172494 5.127499176 5.110714775 2.124854552 2.231172494 Abs Transmittance 0.737313539 0.737576544 0.12825806 0.142814874 0.737313539 0.737576544 0.128258060 0.142814874 CRI1 0.2755936 0.253167993 0.274953101