In paragraph 3.1. of Annex 4, Part 1 the position of the photometer head, the reference axis and the directions are clearly described. If the surface reflection is on the opposite side of the source from the photometer head, which is given at an angle of (β1 = -5°), the surface reflection has no influence on the measurement. This is true for the measurement of RI values as well as for colour measurement.
The proposed solution is based on an existing description in UN Regulation No. 27 (namely paragraph 2.6. of Annex 6) concerning the procedure to follow in case of a surface reflection for both colour measurement and CIL measurement.
32. The expert from GTB proposed aligning the procedure in case of a surface reflection for measurement of both coefficient of luminous intensity and colour (ECE/TRANS/WP.29/GRE/2023/21). GRE adopted the proposal and requested the secretariat to submit it for consideration and vote at the March 2024 sessions of WP.29 and AC.1 as part of draft Supplement 2 to the 01 series of amendments to UN Regulation No. 150.
33. The expert of EC held the view that the justification part of ECE/TRANS/WP.29/GRE/2023/21 was too complicated and expressed the wish that future amendment proposals be accompanied by simpler explanations.
| WP.29/2024/27 |