Page:Colorimetry104nime.djvu/44

Table 13. ASTM Union colorimeter standards, Lovibond analysis, luminous transmittance, $\tau _{v}$, chromaticity coordinates, $x,y$, for CIE source C, NPA color names, nearest chromaticity match on the new ASTM color scale, and Munsell Book notations

Union color Number	Lovibond analysis			Lumi­nous transmit­tance, $\tau _{v}$	Chromaticity coordinates		National Petroleum Association names	Nearest chromaticity match on ASTM scale	Munsell Book notations
	Red	Yellow	Blue		x	y
1.0	0.12	2.4		0.751	0.349	0.382	Lily white	0.55g	10Y	9.6/3.8
1.5	.60	8.0		.654	.400	.446	Cream white	1.05g	8Y	8.8/8.0
2.0	2.5	26.0		.443	.472	.476	Extra pale	1.85p	3Y	7.2/12
2.5	4.6	27.0		.365	.498	.457	Extra lemon pale	2.35p	10YR	6.0/12
3.0	6.9	32.0		.287	.525	.440	Lemon pale	2.85p	7YR	5.7/13
3.5	9.4	45.0		.211	.556	.423	Extra Orange pale	3.5p	4YR	5.0/14
4.0	14.0	50.0	0.55	.096	.591	.400	Orange pale	4.2p	2YR	3.2/12
4.5	21.0	56.0	.55	.065	.620	.376	Pale	4.9	1YR	2.6/12
5.0	35.0	93.0		.036	.653	.347	Light red	5.8	1YR	2.2/9.5
6.0	60.0	60.0	.55	.017	.676	.323	Dark red	6.5	1YR	1.3/8.5
7.0	60.0	106.0	1.8	.0066	.684	.316	Claret red	6.75	1YR	0.6/4.5
8.0	166.0	64.0		.0020	.714	.286		7.8	1YR	0.2/1.4

 

Table 14. ASTM color standards for petroleum products. Chromaticity coordinates in the CIE and VC8 system with, tolerances, luminous transmittances with tolerances, and nearest chromaticity matches on the Union scale, the 35-yellow plus N-red Lovibond scale used for vegetable oils, and the Gardner scale used for paint vehicles

ASTM color number	Chromaticity coordinates				Luminous transmittance			Nearest chromaticity match on
	CIE-system		UCS-system[1]					Union color scale	Lovibond 35Y + NR scale N	Gardner color scale
	x	y	r	g	$\tau _{v}$
0.5	0.3469	0.3739	0.462	0.473	0.86	±	0.06	0.9 p		5.3p
1.0	.3945	.4359	.489	.475	.77	±	.06	1.45p		8.0p
1.5	.4473	.4781	.521	.454	.67	±	.06	1.8 g	1.5p	10.0
2.0	.4876	.4826	.552	.442	.55	±	.06	2.15g	3.3	11.4g
2.5	.5192	.4711	.582	.416	.44	±	.04	2.65g	5.3g	12.3g
3.0	.5437	.4517	.611	.388	.31	±	.04	3.1 g	7.7 g	13.2
3.5	.5648	.4308	.640	.359	.22	±	.04	3.5 g	10.3 g	13.9
4.0	.5855	.4102	.671	.328	.152	±	.022	3.85g	13.5g	14.8
4.5	.6053	.3906	.703	.296	.109	±	.016	4.2 g	17.5g	15.6
5.0	.6257	.3742	.736	.264	.081	±	.012	4.55	23 g	16.3
5.5	.6435	.3565	.770	.230	.058	±	.010	4.85	30	17.2
6.0	.6604	.3395	.805	.195	.040	±	.008	5.3	41	18.1
6.5	.6765	.3235	.841	.159	.026	±	.006	6.0	57
7.0	.6913	.3086	.877	.123	.016	±	.004	7.2	82
7.5	.7059	.2941	.915	.085	.0081	±	.0016	7.7
8.0	.7204	.2796	.956	.044	.0025	±	.0006

chromometer is a device for carrying out this comparison. It consists of an artificial daylight lamp meeting the same requirements as given above for the ASTM Union colorimeter, a graduated tube for the oil specimen, a holder for the glass color standards, and a prism eyepiece to bring into juxtaposition the two fields to be compared. There is an open ungraduated tube beneath the holder for the glass standards that serves to duplicate to a degree on the standard side of the instrument the effect of light multiply reflected within the specimen tube. The glass standards consist of two whole disks and one "one-half" disk; these standards must have luminous transmittances, $\sigma _{v}$, and chromaticity coordinates, $x,y$, for source C, as follows:

	Whole disks	One-half disks
$\tau _{v}$	0.800 to 0.865	0.888 to 0.891
$x$	.342 to  .350	.327 to  .331
$y$	.367 to  .378	.344 to  .350
$z$	.272 to  .291	.319 to  .330

Oils having colors closely resembling that of distilled water are graded on the Saybolt chromometer by comparison with the half disk; more yellowish oils by one or two whole disks. The depth of oil yielding the closest color match with the glass disk is found by a prescribed procedure [5],

1. Tolerances on chromaticity coordinates, r,g,h (b = 1-r-g), are ±0.006.