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Choice of Light Colour
Two key factors must be considered when specifying the colour of a fluorescent tube - the correlated colour temperature (CCT) and the colour rendering index (CRI). The colour temperature is largely a matter of personal taste. The general preference is to use cool colours for a business-like atmosphere (e.g. in offices, factories, shops) and warm colours for a social atmosphere (e.g. in hotels and the home).
However there is considerable variation between different countries in terms of the most popular fluorescent light colour. The clear favourite in both continental Europe and North America is 4000K Neutral White. In the UK however the preference is for 3500K tubes, which strikes a balance between creating a professional atmosphere whilst providing a feeling of warmth for a friendly working environment. In the colder climes of the Nordic countries the 3000K lamps are preferred, to provide a feeling of warmth when coming indoors. Conversely the hot conditions in Southern Europe lead their populations to prefer a cold colour light, which provides the perception of escaping out of the heat into a cool and comfortable interior space. In all of these countries however, the warmest 2700K tubes hold court in domestic and residential lighting where they come close to the favoured appearance of the dominant incandescent and halogen lighting. These local preferences are contrasted strongly by practically the whole of Asia, where practically all sales are for the cool daylight lamps of 5000-6500K, even for residential lighting. Some more detailed applications for the different colour temperatures are detailed in Figure F2.
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Figure F2 - Typical Applications for different Colour Temperatures |
When choosing the desired light colour it is crucial to stay within the boundaries of the empirically determined Kruithof diagram (Figure F3), so as to achieve a natural colour appearance. The use of high colour temperatures at low illumination levels results in a depressing visual environment where colours appear flat and dull. Conversely the use of warm colour temperatures at high illumination levels yields an unpleasant insipid yellow hue to the surroundings which disturb the feeling of well-being. The matching of the illumination level to the desired colour temperature is a key point that is often overlooked in modern lighting design. |
Figure F3 - The Kruithof Diagram |
Colour Coding Nomenclature
With the launch of the first fluorescent tubes, the choice of colours was restricted to a single shade of 'White' plus seven vibrant colours. The white was a neutral colour having a CCT of around 4000K. Soon this was joined by a lower colour temperature known as 'Mellow' or 'Warm White'. This was rapidly followed by a high colour temperature light intended to better match the 5600K of natural daylight, and these lamps were simply called 'Daylight'. During the 1950s and in particular following the invention of the halophosphate materials, dozens of additional shades of white made their debut, and these were later augmented by the so called Deluxe colours - which offered the same colour temperature as earlier tubes but with superior colour rendering properties. Around this time most manufacturers adopted a coding system in which a completely arbitrary two-digit number was introduced to define each colour.
This situation propagated until the early 1990s, by which time there was quite some confusion in the market. This was not only because of the great number of different colours and codes, but also because each manufacturer and global region had its own nomenclature. The situation was rationalised following the introduction of a highly logical three-digit colour coding system by GE-Thorn in 1990. Such was the simplicity of this system that during the rest of that decade it was adopted by most other manufacturers, and also extended to other discharge lamps. The general structure is illustrated below in Table F2, where the first digit defines the colour rendering group while the second and third denote the correlated colour temperature.
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Code |
1st digit = Colour Rendering |
2nd + 3rd = Colour Temperature |
530 |
5 = Ra 50-59 (now 47-56) |
30 = 3000 K |
640 |
6 = Ra 60-69 (now 57-66) |
40 = 4000 K |
726 |
7 = Ra 70-69 (now 67-76) |
26 = 2600 K |
850 |
8 = Ra 80-89 (now 77-86) |
50 = 5000 K |
965 |
9 = Ra 90-99 (now 87-100) |
65 = 6500 K |
Table F2 - Examples of Three-Digit Colour Codes |
Some manufacturers continue to dual-brand fluorescent tubes with their original two-digit serial codes in addition to the modern 3-digit system. There is no logic to these older codes and they cannot be deciphered to reveal the colour properties without reference to the manufacturer's literature. A fairly comprehensive cross-reference table of both historic as well as modern fluorescent colour codes from the key manufacturers is provided below in Table F3.
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Halophosphate Whites
(Nominal data for F40T12 lamps)
Description |
Code |
Philips |
Osram |
Sylvania |
GE-Thorn |
American |
CCT |
CRI |
CCx |
CCy |
lm/W |
Extra Warm White |
726 |
- |
- |
- |
Home-lite |
- |
2600 |
73 |
0.454 |
0.400 |
61 |
Warm White |
530 |
Warm 29 |
HNI 30 |
WW 129 |
Warm 29 |
Warm White |
3000 |
52 |
0.440 |
0.403 |
74 |
White |
535 |
UK White 35 |
23 |
W 135 |
White 35 |
White |
3500 |
55 |
0.409 |
0.394 |
76 |
Cool White |
640 |
White 33 |
HNH 20 |
CW 133 |
Cool 33 |
Cool White |
4200 |
65 |
0.370 |
0.380 |
75 |
Universal White |
740 |
Natural 25 |
HNW 25 |
UW 125 |
Universal 25 |
- |
4000 |
75 |
0.380 |
0.380 |
65 |
Daylight |
765 |
Daylight 54 |
10 / HNT 15 |
D 154 |
Tropical Day. |
Daylight |
6500 |
75 |
0.313 |
0.340 |
63 |
Deluxe Whites (Obsolete)
(Nominal data for F40T12 lamps)
Description |
Code |
Philips |
Osram |
Sylvania |
GE-Thorn |
American |
CCT |
CRI |
CCx |
CCy |
lm/W |
DX Extra Warm |
927 |
WWDX 27 |
Interna 39 |
Incand. Fluo. |
- |
- |
2650 |
94 |
0.461 |
0.418 |
44 |
DX Warm White |
830 |
Softone 32 |
HNI-Z 32 |
WWX |
DX Warm 32 |
DX WW |
3000 |
85 |
0.439 |
0.402 |
50 |
Plus White |
736 |
- |
HNI-DX 31 |
- |
Plus White 36 |
- |
3600 |
74 |
0.399 |
0.382 |
73 |
DX White |
839 |
34 |
HNW-Z 22 |
CWX |
- |
DX White |
3850 |
85 |
0.382 |
0.370 |
50 |
DX Cool White A |
940 |
Trucolor 38 |
HNG 35 |
- |
°KolorRite 38 |
DX Cool |
4000 |
92 |
0.381 |
0.377 |
40 |
DX Cool White B |
941 |
Trucolor 37 |
HNW-DX 21 |
- |
- |
- |
4100 |
97 |
0.374 |
0.370 |
45 |
DX Daylight 5000K |
950 |
Graphica 47 |
19 |
- |
- |
Chroma 50 |
5000 |
98 |
- |
- |
46 |
DX Daylight 6200K |
962 |
Col. Match 55 |
- |
DDX 155 |
Northlight 55 |
D65 |
6200 |
94 |
0.313 |
0.323 |
48 |
DX Daylight +UV |
965 |
- |
- |
- |
Artificial Day |
- |
6500 |
95 |
0.313 |
0.329 |
37 |
DX Daylight 7500K |
975 |
Daylight 57 |
- |
- |
Abbot-Gibson |
Chroma 75 |
7500 |
94 |
- |
- |
47 |
Triphosphor Deluxe 80 Series
(Nominal data for F36T8 lamps)
Description |
Code |
Philips |
Osram |
Sylvania |
GE-Thorn |
American |
CCT |
CRI |
CCx |
CCy |
lm/W |
Tri DX Extra Warm |
827 |
Incand DX 82 |
Lumilux 41 |
Home DX 182 |
Polylux 827 |
- |
2700 |
85 |
0.463 |
0.417 |
95 |
Tri DX Warm |
830 |
WarmDX 83 |
Lumilux 31 |
WarmDX 183 |
Polylux 830 |
- |
3000 |
85 |
0.440 |
0.405 |
95 |
Tri DX White |
835 |
UK White 835 |
Lumilux 26 |
White DX 835 |
Polylux 835 |
SPX35 |
3500 |
85 |
0.415 |
0.400 |
95 |
Tri DX Cool White |
840 |
White DX 84 |
Lumilux 21 |
Buro 184 |
Polylux 840 |
SPX40 |
4000 |
85 |
0.380 |
0.380 |
95 |
Tri DX Daylight 5K |
850 |
Day DX 85 |
- |
DDX 185 |
- |
- |
5000 |
85 |
0.346 |
0.359 |
92 |
Tri DX Daylight 6K |
860 |
- |
- |
DDX 186 |
Polylux 860 |
- |
6000 |
85 |
0.346 |
0.359 |
90 |
Tri DX Daylight 6K |
865 |
Cool Day 86 |
Lumilux 11 |
- |
- |
- |
6500 |
85 |
- |
- |
90 |
Triphosphor Super Deluxe 90 Series
(Nominal data for F36T8 lamps)
Description |
Code |
Philips |
Osram |
Sylvania |
GE-Thorn |
American |
CCT |
CRI |
CCx |
CCy |
lm/W |
Tri SDX Ex. Warm |
927 |
Incand DX 92 |
- |
- |
- |
- |
2700 |
95 |
- |
- |
63 |
Tri SDX Warm |
930 |
93 |
Lumilux 32 |
WarmDX 193 |
Polylux 930 |
- |
3000 |
95 |
0.435 |
0.401 |
65 |
Tri SDX Cool |
940 |
94 |
Lumilux 22 |
Buro 194 |
Polylux 940 |
- |
4000 |
95 |
0.387 |
0.371 |
65 |
Tri SDX Day 5K |
950 |
95 |
ColorProof 12 |
- |
Polylux 950 |
- |
5000 |
98 |
0.344 |
0.354 |
65 |
Tri SDX Day 6K |
960 |
96 |
- |
- |
Polylux 960 |
- |
6000 |
98 |
0.309 |
0.324 |
65 |
Tri SDX Day +UV |
965 |
BioLight 96 |
Biolux 72 |
Activa 172 |
- |
- |
6500 |
98 |
0.313 |
0.335 |
65 |
Description |
Philips |
Osram |
Sylvania |
GE-Thorn |
CCT |
CRI |
CCx |
CCy |
lm/W |
Blue |
18 |
67 / HNE64 |
Blue |
Blue |
- |
- |
0.187 |
0.143 |
18 |
Green |
17 |
66 / HNE63 |
Green |
Green |
7000 |
22 |
0.239 |
0.622 |
70 |
Gold (Halophosphate +Cadmium Filter) |
- |
62 / HNE62 |
Gold |
Gold |
5000 |
98 |
0.508 |
0.488 |
36 |
Yellow (Modern Cadmium-free type) |
16 |
- |
Yellow |
- |
2200 |
34 |
0.534 |
0.464 |
- |
Orange |
- |
- |
Orange |
- |
- |
- |
0.632 |
0.361 |
- |
Peach |
- |
- |
- |
Peach |
- |
- |
- |
- |
44 |
Pink |
- |
61 / HNE61 |
Pink |
Pink |
- |
- |
0.548 |
0.310 |
19 |
Red (Halophosphate + Cadmium Filter) |
- |
- |
Red |
Red |
- |
- |
0.700 |
0.299 |
4 |
Red (Modern Cadmium-free type) |
15 |
60 |
New Red |
- |
- |
- |
0.713 |
0.285 |
- |
Description |
Philips |
Osram |
Sylvania |
GE-Thorn |
CCT |
CRI |
CCx |
CCy |
lm/W |
Radar Blue |
- |
- |
- |
Radar Blue |
- |
- |
0.255 |
0.317 |
- |
Radar Red |
- |
- |
- |
Radar Red |
- |
- |
0.565 |
0.277 |
- |
Shop Lighting - Extra Warm |
36 |
Natura 36 |
Natural 136 |
Natural |
4000 |
90 |
0.378 |
0.365 |
50 |
Food Display (Bread, Patisserie etc.) |
Shoplight 76 |
Natura 76 |
FoodStar 176 |
DX Natural |
3600 |
92 |
0.390 |
0.356 |
50 |
Meat Display (Basic CRI) |
79 |
- |
- |
- |
3800 |
74 |
0.369 |
0.317 |
45 |
Meat Display (High CRI) |
- |
- |
- |
Rosetta |
3200 |
86 |
0.380 |
0.310 |
45 |
Meat Display with reduced myoglobin |
- |
- |
Gourmet 175 |
- |
3800 |
85 |
0.380 |
0.340 |
- |
Plant Growth Spectrum |
89 |
Fluora 77 |
GroLux |
Super-Gro |
6200 |
37 |
0.325 |
0.261 |
30 |
Plant Growth Wide Spectrum |
- |
- |
GroLux WS |
- |
- |
- |
- |
- |
41 |
Aquarium Fresh Water |
Aquarelle |
- |
AquaStar 174 |
- |
10000 |
71 |
0.304 |
0.239 |
68 |
Aquarium Daylight UV Stop coating |
- |
- |
DaylightStar |
- |
5000 |
85 |
0.346 |
0.359 |
95 |
Aquarium Coral growth |
- |
- |
CoralStar |
- |
- |
- |
0.176 |
0.045 |
- |
Reptile UVB Vitamin D3 Synthesis |
- |
- |
ReptiStar |
- |
6700 |
95 |
0.308 |
0.338 |
- |
SAD Treatment |
- |
Sky White |
- |
- |
8000 |
85 |
- |
- |
- |
Description |
Philips |
Osram |
Sylvania |
GE-Thorn |
Peak l |
l10% |
l90% |
Blacklight Blue (Fluorescence Effects) |
08 |
73 |
BLB |
BLB |
365 |
350 |
390 |
Blacklight 350nm (Photochemistry) |
Actinic 09 |
- |
BL 350 |
BL |
350 |
320 |
395 |
Blacklight Pure UVA (Insect Traps) |
10 |
- |
BL Quantum |
- |
370 |
350 |
390 |
Actinic 365nm (Diazo Copying) |
Actinic 05 |
78 |
- |
- |
365 |
320 |
420 |
Super Actinic 420nm (Diazo Copying) |
Actinic 03 |
HNPs 70 |
- |
- |
420 |
400 |
440 |
Actinic Green (Photocopiers) |
Actinic 14 |
72 |
- |
- |
- |
- |
- |
Reprography Blue |
66 |
- |
- |
- |
- |
- |
- |
Reprography Green |
50 |
- |
- |
- |
542 |
- |
- |
Germicidal - Destruction of DNA |
TUV |
- |
Germicidal |
Germicidal |
254 |
- |
- |
Medical - Psoriasis |
Medical 01 |
- |
- |
- |
312 |
- |
- |
Medical - Hyperbilirubinaemia |
Medical 52 |
71 |
Blue |
Bilirubin Blue |
450 |
- |
- |
Tanning Basic - Closed Glass |
Cleo 09 |
- |
PBC |
- |
352 |
320 |
390 |
Tanning Professional - Open Glass |
Cleo Prof 109 |
- |
PBO |
- |
352 |
300 |
370 |
Tanning Pink Effect |
Cleo Pink 209 |
- |
- |
- |
352 |
320 |
390 |
Tanning UVB / Psoriasis |
12 |
- |
- |
- |
307 |
280 |
315 |
Table F3 - Cross-Reference Table of Fluorescent Colour Codes |
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