Table I
Maximum errors (in μrd) of computed values of correlated color temperature, resulting from use of various sets of isotemperature lines.
Range of correlated color temperature (μrd) | Spacing of isotemperature lines (μrd) |
---|
5 | 10 | 25 | 50 | 100 |
---|
Series I | 1–100 | 0.03 | 0.10 | 0.60 | 1.99 | 5.28 |
| 100–200 | 0.01 | 0.02 | 0.05 | 0.17 | 0.32 |
| 200–300 | 0.02 | 0.02 | 0.04 | 0.17 | 0.65 |
| 300–400 | 0.02 | 0.02 | 0.03 | 0.08 | 0.29 |
| 400–500 | 0.02 | 0.02 | 0.03 | 0.09 | 0.29 |
| 500–600 | 0.02 | 0.02 | 0.05 | 0.14 | 0.49 |
Series II | 1–100 | 0.03 | 0.11 | 0.64 | 2.13 | 5.74 |
| 100–200 | 0.01 | 0.02 | 0.07 | 0.15 | 0.13 |
| 200–300 | 0.01 | 0.02 | 0.05 | 0.20 | 0.84 |
| 300–400 | 0.02 | 0.02 | 0.04 | 0.16 | 0.61 |
| 400–500 | 0.02 | 0.02 | 0.05 | 0.15 | 0.54 |
| 500–600 | 0.02 | 0.02 | 0.06 | 0.18 | 0.65 |
Series III | 1–100 | 0.03 | 0.09 | 0.56 | 1.83 | 4.75 |
| 100–200 | 0.02 | 0.01 | 0.04 | 0.20 | 0.56 |
| 200–300 | 0.02 | 0.02 | 0.03 | 0.13 | 0.43 |
| 300–400 | 0.02 | 0.02 | 0.02 | 0.04 | 0.19 |
| 400–500 | 0.02 | 0.02 | 0.02 | 0.03 | 0.03 |
| 500–600 | 0.02 | 0.01 | 0.04 | 0.11 | 0.33 |
Table II
Thirty one isotemperature lines.
Correlated color temperature | Intersection with planckian locus | Slope in u–v diagram |
---|
μrd | K | u | v |
---|
0 | ∞ | 0.18006 | 0.26352 | −0.2434 |
10 | 100 000 | 0.18065 | 0.26589 | −0.2548 |
20 | 50 000 | 0.18132 | 0.26845 | −0.2687 |
30 | 33 333 | 0.18208 | 0.27118 | −0.2854 |
40 | 25 000 | 0.18293 | 0.27407 | −0.3047 |
50 | 20 000 | 0.18388 | 0.27708 | −0.3267 |
60 | 16 667 | 0.18494 | 0.28020 | −0.3515 |
70 | 14 286 | 0.18611 | 0.28340 | −0.3790 |
80 | 12 500 | 0.18739 | 0.28666 | −0.4094 |
90 | 11 111 | 0.18879 | 0.28995 | −0.4426 |
100 | 10 000 | 0.19031 | 0.29325 | −0.4787 |
125 | 8 000 | 0.19461 | 0.30139 | −0.5817 |
150 | 6 667 | 0.19960 | 0.30918 | −0.7043 |
175 | 5 714 | 0.20523 | 0.31645 | −0.8484 |
200 | 5 000 | 0.21140 | 0.32309 | −1.017 |
225 | 4 444 | 0.21804 | 0.32906 | −1.216 |
250 | 4 000 | 0.22507 | 0.33436 | −1.450 |
275 | 3 636 | 0.23243 | 0.33901 | −1.728 |
300 | 3 333 | 0.24005 | 0.34305 | −2.061 |
325 | 3 077 | 0.24787 | 0.34653 | −2.465 |
350 | 2 857 | 0.25585 | 0.34948 | −2.960 |
375 | 2 667 | 0.26394 | 0.35198 | −3.576 |
400 | 2 500 | 0.27210 | 0.35405 | −4.355 |
425 | 2 353 | 0.28032 | 0.35575 | −5.365 |
450 | 2 222 | 0.28854 | 0.35713 | −6.711 |
475 | 2 105 | 0.29676 | 0.35822 | −8.572 |
500 | 2 000 | 0.30496 | 0.35906 | −11.29 |
525 | 1 905 | 0.31310 | 0.35968 | −15.56 |
550 | 1 818 | 0.32119 | 0.36011 | −23.20 |
575 | 1 739 | 0.32920 | 0.36038 | −40.41 |
600 | 1 667 | 0.33713 | 0.36051 | −113.8 |
Table III
Maximum errors of computed values of correlated color temperature, based on use of the 31 isotemperature lines listed in Table II.
Range | Maximum error |
---|
μrd | K | μrd | K |
---|
1–10 | 1 000 000–100 000 | 0.11 | ⋯ |
10–20 | 100 000–50 000 | 0.09 | 450 |
20–30 | 50 000–33 333 | 0.08 | 140 |
30–40 | 33 333–25 000 | 0.08 | 65 |
40–50 | 25 000–20 000 | 0.07 | 36 |
50–60 | 20 000–16 667 | 0.05 | 18 |
60–70 | 16 667–14 286 | 0.04 | 9.6 |
70–80 | 14 286–12 500 | 0.03 | 5.4 |
80–90 | 12 500–11 111 | 0.03 | 3.6 |
90–100 | 11 111–10 000 | 0.03 | 2.8 |
100–125 | 10 000–8 000 | 0.07 | 5.9 |
125–150 | 8 000–6 667 | 0.03 | 1.5 |
150–175 | 6 667–5 714 | 0.05 | 1.8 |
175–200 | 5 714–5 000 | 0.03 | 1.0 |
200–225 | 5 000–4 444 | 0.04 | 1.0 |
225–250 | 4 444–4 000 | 0.05 | 0.8 |
250–275 | 4 000–3 636 | 0.05 | 0.7 |
275–300 | 3 636–3 333 | 0.04 | 0.5 |
300–325 | 3 333–3 077 | 0.03 | 0.3 |
325–350 | 3 077–2 857 | 0.03 | 0.2 |
350–375 | 2 857–2 667 | 0.02 | 0.2 |
375–400 | 2 667–2 500 | 0.03 | 0.2 |
400–425 | 2 500–2 353 | 0.04 | 0.2 |
425–450 | 2 353–2 222 | 0.04 | 0.2 |
450–475 | 2 222–2 105 | 0.05 | 0.2 |
475–500 | 2 105–2 000 | 0.04 | 0.2 |
500–525 | 2 000–1 905 | 0.04 | 0.2 |
525–550 | 1 905–1 818 | 0.05 | 0.2 |
550–575 | 1 818–1 739 | 0.05 | 0.2 |
575–600 | 1 739–1 667 | 0.06 | 0.2 |
Table IV
Maximum errors of computed values of correlated color temperature, based on the use of only nine isotemperature lines (0, 25, 50, 100, 200, 300, 400, 500, 600 μrd).
Range | Maximum error |
---|
μrd | K | μrd | K |
1–25 | 1 000 000–40 000 | 0.6 | ⋯ |
25–50 | 40 000–20 000 | 0.5 | 370 |
50–100 | 20 000–10 000 | 0.9 | 180 |
100–200 | 10 000–5 000 | 0.6 | 31 |
200–300 | 5 000–3 333 | 0.8 | 15 |
300–400 | 3 333–2 500 | 0.6 | 5.3 |
400–500 | 2 500–2 000 | 0.5 | 2.8 |
500–600 | 2 000–1 667 | 0.7 | 2.2 |
Table V
Correlated color temperatures and distribution temperatures (400–700 nm) of 16 sources.
Code | Description of source | Correlated color temperature (K) | Distribution temperature (K) | Percentage difference between test source and planckian radiator at Td |
---|
rms | max | Wavelength of max difference (nm) |
---|
SF | Tungsten, strip filament | 2060 | 2055 | 0.5 | 1.0 | 400 |
CF1 | Tungsten, coil filament | 2032 | 2030 | 0.2 | 0.3 | 700 |
CF2 | Tungsten, coil filament | 2369 | 2363 | 0.5 | 1.4 | 410 |
CF3 | Tungsten, coil filament | 2595 | 2589 | 0.4 | 0.7 | 550 |
CF4 | Tungsten, coil filament | 2845 | 2841 | 0.4 | 1.0 | 400 |
TI1 | Tungsten-iodine 1000W | 3084 | 3089 | 0.2 | 0.5 | 400 |
TI2 | Tungsten-iodine 300W | 2820 | 2857 | 1.8 | 3.7 | 405 |
TI3 | Tungsten-iodine 200W | 3077 | 3129 | 2.1 | 4.1 | 415 |
B | CIE standard illuminant B | 4871 | 4648 | 7.5 | 30.4 | 400 |
C | CIE standard illuminant C | 6770 | 6211 | 9.8 | 39.2 | 400 |
D6500 | CIE standard illuminant D6500 | 6499 | 6201 | 6.9 | 16.7 | 400 |
E | Equi-energy illuminant | 5452 | 5509 | 5.9 | 13.8 | 400 |
XA | Xenon arc | 5689 | 5493 | 9.7 | 43.6 | 470 |
CA | Carbon arc | 6344 | 6512 | 7.2 | 16.6 | 400 |
FT1 | Tungsten lamp and Corning 5900 filter | 6373 | 5914 | 10.6 | 26.3 | 400 |
FT2 | Tungsten lamp with mirror, Corning 5900 filter and opal glass | 6480 | 6239 | 10.1 | 28.2 | 400 |
Table VI
Distribution temperatures (400–700 nm) of eight incandescent sources calculated by use of the indicated wavelength intervals. (The figures in parentheses are rms percentage deviations.)
Source | Correlated color temperature (K) | Distribution temperature (K) |
---|
5 nm | 10 nm | 20 nm | 50 nm | 100 nm |
---|
SF | 2060 | 2055(0.5) | 2055(0.5) | 2055(0.5) | 2055(0.6) | 2055(0.6) |
CF1 | 2032 | | 2030(0.2) | 2030(0.2) | 2030(0.2) | 2030(0.1) |
CF2 | 2369 | | 2363(0.5) | 2366(0.4) | 2367(0.4) | 2369(0.2) |
CF3 | 2595 | | 2589(0.4) | 2589(0.4) | 2589(0.5) | 2589(0.5) |
CF4 | 2845 | 2841(0.4) | 2841(0.4) | 2841(0.4) | 2840(0.5) | 2840(0.6) |
TI1 | 3084 | 3089(0.2) | 3089(0.2) | 3088(0.2) | 3088(0.3) | 3087(0.3) |
TI2 | 2820 | 2857(1.8) | 2858(1.9) | 2859(1.9) | 2860(2.0) | 2865(2.2) |
TI3 | 3077 | 3129(2.1) | 3129(2.1) | 3132(2.1) | 3131(2.1) | 3137(2.2) |
Table VII
Distribution temperatures of eight incandescent sources in four wavelength ranges. (The figures in parentheses are rms percentage deviations.)
Source | Correlated color temperature (K) | Distribution temperature (K) |
---|
400–700 nm | 380–770 nm | 380–700 nm | 400–770 nm |
---|
SF | 2060 | 2055(0.5) | 2054(1.9) | 2049(1.9) | 2059(0.8) |
CF1 | 2032 | 2030(0.2) | 2031(0.4) | 2029(0.2) | 2032(0.4) |
CF2 | 2369 | 2363(0.5) | 2367(1.0) | 2367(1.1) | 2364(0.5) |
CF3 | 2595 | 2589(0.4) | 2591(0.5) | 2588(0.4) | 2593(0.5) |
CF4 | 2845 | 2841(0.4) | 2844(0.7) | 2838(0.5) | 2846(0.6) |
TI1 | 3084 | 3089(0.2) | 3093(0.4) | 3090(0.3) | 3093(0.4) |
TI2 | 2820 | 2858(1.9) | 2858(2.1) | 2867(2.0) | 2850(1.8) |
TI3 | 3077 | 3129(2.1) | 3129(2.2) | 3140(2.2) | 3119(2.0) |
Table VIII
Distribution temperatures of two sources for the indicated wavelength ranges, between 230 and 800 nm. (The figures in parentheses are rms percentage deviations.)
Source | Wavelength range (nm) | Distribution temperature (K) |
---|
Tungsten-iodine | 300–400 | 3125(0.9) |
| 400–700 | 3107(2.6) |
| 700–800 | 3148(0.2) |
| 300–800 | 3124(2.9) |
Strip filament (tungsten) | 230–380 | 2725(2.6) |
| 400–700 | 2843(0.6) |
| 700–800 | 2925(0.3) |
| 230–800 | 2802(5.1) |
Table IX
Daylight distribution temperatures (400–700 nm) of eight sources.
Source | Daylight distribution temperature (K) | Percentage deviations | Wavelength of max (nm) |
---|
rms | max |
---|
B | 4924 | 7.4 | 26.4 | 430 |
C | 6445 | 8.8 | 25.9 | 400 |
D6500 | 6500 | 0.0 | 0.0 | ⋯ |
E | 5960 | 12.4 | 26.8 | 400 |
XA | 5885 | 12.8 | 37.6 | 690 |
CA | 7044 | 12.8 | 31.4 | 400 |
FT1 | 6179 | 11.6 | 27.2 | 700 |
FT2 | 6507 | 10.1 | 19.7 | 430 |