SAE AS 25050B:2017 – (R)Colors,Aeronautical Lights and Lighting Equipment, General Requirements For.
3.4 Standards
NOTE: Most color testing is now done with spectroradiomelers rather than by comparison photometry, making the remainder of this document obsolete. It is included for use by those with older equipment or to support the manufacturing of replacement lights that were originally designed and qualified using older methods.
Each color standard shall consist of a set of two or more filters and an illuminani of designated color temperature. One filter designated as the pale limir shall rep-esent the minimum coloration that is acceptable. In general. this filter shall also represent a hue limit. One or more filters of the set, designated as lransmission standards, shall provide a basis for measuring the transmission of ware that is near the minimum acceptable transmission for its grade. In the case of grade A ware or other ware of similar cwomaticity. the pale limit may be used as a basis for measuring the transmission. When a second chromaticity limit is deemed advisable, an addit,onal filter may be used, or a transmisslon standard may be used as such, and these filters shall be designated as red limit, ‘blue limit. etc. For identification green. separate yeflow.green and blue.green standards are required.
3.4.2 Similanty of Material
The chromaticity characteristics ol the transmission standards shall be the same as those of the pale limit according to the definition (see 6.3.3).
3.4.3 Uniformity of Coloring
The coloring matter shall be uniformly distributed throughout the material, except in the case of selenium red and yellow lifters for which a slight variation will be accepted as unavoidable.
3,4.4 Dimensions
The standard lifters shall be cut square, not more than 5.05 cm (1.99 inches) nor less than 4.90 cm (1.93 inches) on each side, and shall be not less than 1.5 mm (0.059 inch) thick.
3.4.5 Optical Oualily
Standard fillers shall have sufficiently plane, parallel, and well-polished faces, and shall be sufficiently free from bubbles, striae. scratches, and other defects so as to be suitable, in the opinion of the National Institute of Standards and Technology (NIST), for certification as standards.
3.4.6 Transmission
The transmission of the standard filters for 2854 K shall be not less than 0.60 times the minimum transmission ratio specified for the ware.
3.5 llluminants
Unless otherwise specified, the color temperatures specified in Table 2 shall be standard for use in the purchase of equment as indicated.
3.6 Color
3,6.1 Chromatioty of Nondiftusing Equipment
When nondiffusing ware or equipment using such ware is procured in accordance with a standard, the light transmitted in every direction that is to be utilized in service shall conform to tho blowing requirements when used with the intended light source as specified in Table 5.
3.6.1.1 Red Ware
The light transmitted by the ware furnished shall not be yellower nor less saturated than the light transmitted by the applicable pale limit.
3.6.1.1.1 Instrument and Panel Lighting Red
The light transmitted by the ware furnished shall not be yellower nor less saturated than the light transmitted by an NBS
3215 filter using illuminant A.
3.6.1.2 Yellow Ware
The light transmitted by the ware furnished shall not be redder than the light transmitted by the applicable red limit, nor greener nor less saturated than the light transmitted by the applicable pale limit.
3.6.1.3 Green Ware
The light transmitted by the ware furnished shall not be less saturated than the light transmitted by the applicable pale hmit, and shall be neither yellower nor bluer than the light transmitted by the applicable yellow and blue limits, respectively.
3.61.4 Aviation-Blue Ware
The light transmitted by the ware furnished shall be not greener nor less saturated than the light transmitted by the pale limit, and when light transmitted by the ware is transmitted in turn through a replica of identification red transmission standard filter designated as NBS 3055A. the light transmitted by the combination shall be not more than 0015 times the light transmitted by the ware without the red filter.
3.6.1.5 Aviation and Instrument Panel Lighting White Colorless Ware
The l.ght transmitted by the ware lumished shall not be noticeably different in chromaticity from the iMuminant.
3.6.1.6 Identification Lunar•White Ware
The light transmitted by the ware furnished shall not be ye’lower than the light transmitted by the pale limit, nor bluer than the light transmitted by the blue limit.
3.6.2 Chromaticity of Diffusing Ware
When diffusing ware, or equçment using such ware, is specified to be in accordance with a standard, the chromaticity of every portion that is designed to be visible in service shall conform to the following requirements when used with the intended light source.as specified in Table 5.
3.6.2.1 Aviation-White Ware
The illuminated surface of the ware shall not appear appreciably different in chromaticity from the surface of the white diffusing standard.