132:. Increasing the pressure of the sodium vapor broadened the sodium emission spectrum so that the light produced had more energy emitted at wavelengths above and below the 589 nm region. The quartz material used in mercury discharge lamps was corroded by high pressure sodium vapor. A laboratory demonstration of a high pressure lamp was carried out in 1959. The development by General Electric of a sintered aluminum oxide material (with magnesium oxide added to improve light transmission) was an important step in construction of a commercial lamp. The material was available in the form of tubing by 1962, but additional techniques were required to seal the tubes and add the necessary electrodes—the material could not be fused like quartz. The end caps of the arc tube would get as hot as 800 °C (1,470 °F) in operation, then cool to room temperature when the lamp was turned off, so the electrode terminations and arc tube seal had to tolerate repeated temperature cycles. This problem was solved by Michael Arendash at the GE Nela Park plant. The first commercial high-pressure sodium lamps were available in 1965 from companies in the United States, the United Kingdom, and the Netherlands; at introduction a 400 watt lamp would produce around 100 lumens per watt.
731:
723:
618:
cause a further increase in current. This will create a runaway effect, and the lamp will jump to the high-current state (#3). Because actual lamps are not designed to handle this much power, this would result in catastrophic failure. Similarly, an anomalous drop in current will drive the lamp to extinction. It is the second state that is the desired operating state of the lamp, because a slow loss of the amalgam over time from a reservoir will have less effect on the characteristics of the lamp than a fully evaporated amalgam. The result is an average lamp life in excess of 20,000 hours.
184:
779:. As a lamp gets older, the maintaining voltage for the arc eventually rises to exceed the maximum voltage output by the electrical ballast. As the lamp heats to this point, the arc fails, and the lamp goes out. Eventually, with the arc extinguished, the lamp cools down again, the gas pressure in the arc tube is reduced, and the ballast can once again cause the arc to strike. The effect of this is that the lamp glows for a while and then goes out, typically starting at a pure or bluish white then moving to a red-orange before going out.
31:
176:
401:
579:
591:
345:(occasionally referred to as yellowscreen) is a film technique that relies on narrowband characteristics of LPS lamp. Color negative film is typically not sensitive to the yellow light from an LPS lamp, but special black-and-white film is able to record it. Using a special camera, scenes are recorded on two spools simultaneously, one with actors (or other foreground objects) and another that becomes a mask for later combination with different
329:). Such lamps emit light on just two dominant spectral lines (with other much weaker lines), and therefore have the least spectral interference with astronomical observation. (Now that production of LPS lamps has ceased, consideration is being given into the use of narrow-band amber LEDs, which are on a similar color spectrum to LPS.) The yellow color of low-pressure sodium lamps also leads to the least visual sky glow, due primarily to the
625:" in order to supply a nearly constant current to the lamp, rather than a constant voltage, thus assuring stable operation. The ballast is usually inductive rather than simply being resistive to minimize energy waste from resistance losses. Because the lamp effectively extinguishes at each zero-current point in the AC cycle, the inductive ballast assists in the reignition by providing a voltage spike at the zero-current point.
168:
409:
662:
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39:
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the amalgam, the higher will be the mercury and sodium vapor pressures in the lamp and the higher will be the terminal voltage. As the temperature rises, the constant current and increasing voltage consumes increasing energy until the operating level of power is reached. For a given voltage, there are generally three modes of operation:
1636:
782:
More sophisticated ignitor designs detect cycling and give up attempting to start the lamp after a few cycles, as the repeated high-voltage ignitions needed to restart the arc reduce the lifetime of the ballast or the ignitor, depending on the ignitor configuration. If power is removed and reapplied,
786:
LPS lamp failure does not result in cycling; rather, the lamp will simply not strike or will maintain the dull red glow of the start-up phase. In another failure mode, a tiny puncture of the arc tube leaks some of the sodium vapor into the outer vacuum bulb. The sodium condenses and creates a mirror
602:
and mercury lies at the coolest part of the lamp and provides the sodium and mercury vapor that is needed to draw an arc. The temperature of the amalgam is determined to a great extent by lamp power. The higher the lamp power, the higher will be the amalgam temperature. The higher the temperature of
504:(CRI) of about 85, greatly resembling the color of an incandescent light. These lamps are often used indoors in cafes and restaurants for aesthetic effect. However, white HPS lamps have higher cost, shorter service lives, and lower light efficiency, and so they cannot compete with HPS at this time.
395:
Spectrum of high-pressure sodium lamp. The yellow-red band on the left is the atomic sodium D-line emission; the turquoise line is a sodium line that is otherwise quite weak in a low pressure discharge, but becomes intense in a high-pressure discharge. Most of the other green, blue, and violet lines
617:
The first and last states are stable, because the lamp resistance is weakly related to the voltage, but the second state is unstable. Any anomalous increase in current will cause an increase in power, causing an increase in amalgam temperature, which will cause a decrease in resistance, which will
120:
The low-pressure sodium arc discharge lamp was first made practical around 1920 owing to the development of a type of glass that could resist the corrosive effects of sodium vapor. These operated at pressures of less than 1 Pa and produced a near monochromatic light spectrum around the sodium
288:
Modern LPS lamps have a service life of about 18,000 hours and do not decline in lumen output with age, though they do increase in energy consumption by about 10% towards end of life. This property contrasts with mercury vapor HID lamps, which become dimmer towards the end of life to the point of
333:
of dark-adapted human vision, causing the eye to be relatively insensitive to the yellow light scattered at low luminance levels in the clear atmosphere. One consequence of widespread public lighting is that on cloudy nights, cities with enough lighting are illuminated by light reflected off the
292:
In 2017 Philips
Lighting, the last manufacturer of LPS lamps, announced they were discontinuing production of the lamps due to falling demand. Initially, production was due to be phased out in the course of 2020, but this date was brought forward and the last lamps were produced at the
722:
239:, which improves their efficiency. Earlier LPS lamps had a detachable dewar jacket (SO lamps). Lamps with a permanent vacuum envelope (SOI lamps) were developed to improve thermal insulation. Further improvement was attained by coating the glass envelope with an infrared
484:. As a noble gas, it does not interfere with the chemical reactions occurring in the operating lamp. The low thermal conductivity minimizes thermal losses in the lamp while in the operating state, and the low ionization potential causes the
145:
135:
Single-crystal artificial sapphire tubes were also manufactured and used for HPS lamps in the early 1970s, with a slight improvement in efficacy, but production costs were higher than for polycrystalline alumina tubes.
774:
As a result, these lamps can be started at a relatively low voltage, but, as they heat up during operation, the internal gas pressure within the arc tube rises, and more and more voltage is required to maintain the
215:
to start the gas discharge. The discharge tube may be linear (SLI lamp) or U-shaped. When the lamp is first started, it emits a dim red/pink light to warm the sodium metal; within a few minutes as the sodium metal
281:(HID) lamps; they emit a softer luminous glow, resulting in less glare. Unlike HID lamps, during a voltage dip low-pressure sodium lamps return to full brightness rapidly. LPS lamps are available with
1177:
787:
on the outer glass, partially obscuring the arc tube. The lamp often continues operating normally, but much of the light generated is obscured by the sodium coating, providing no illumination.
232:
wavelength (actually two dominant spectral lines very close together at 589.0 and 589.6 nm). The colors of objects illuminated by only this narrow bandwidth are difficult to distinguish.
730:
432:. They have also been widely used for outdoor area lighting, such as on roadways, parking lots, and security areas. Understanding the change in human color vision sensitivity from
266:. This high efficiency is partly due to the light emitted being at a wavelength near the peak sensitivity of the human eye. They are used mainly for outdoor lighting (such as
1860:
121:
emission lines at 589.0 and 589.56 nanometres wavelength. The yellow light produced by these limited the range of applications to those where color vision was not required.
179:
Spectrum of a low-pressure sodium lamp. The intense yellow band is the atomic sodium D-line emission, comprising about 90% of the visible light emission for this lamp type.
1691:
1023:
USA patent US3737717A, Arendash, Michael, "High intensity lamp containing thermal shorting fuse", published 1972-03-13, issued 1973-06-05, assigned to
General Electric Co.
1634:, Arendash, Michael, "High intensity lamp containing thermal shorting fuse", published 1972-03-13, issued 1973-06-05, assigned to General Electric Co
1449:
2288:
1290:, Preserving the Astronomical Sky, Proceedings of IAU Symposium 196, vol. 196, Vienna, Austria: International Astronomical Union (published 2001), p. 81,
1162:
808:
1207:
277:
LPS lamps are similar to fluorescent lamps in that they are a low-intensity light source with a linear lamp shape. They do not exhibit a bright arc as do
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903:
424:
High-pressure sodium (HPS) lamps have been widely used in industrial lighting, especially in large manufacturing facilities, and are commonly used as
77:. Low-pressure sodium lamps are highly efficient electrical light sources, but their yellow light restricts applications to outdoor lighting, such as
871:
742:, caused by a loss of sodium in the arc. Sodium is a highly reactive element and is lost in a reaction with the aluminum oxide of the arc tube. The
1252:
1420:
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under low-pressure sodium lamps. Both appear black, even though the car on the left is bright red, while the car on the right is actually black.
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A variation of the high-pressure sodium introduced in 1986, the White HPS has a higher pressure than the typical HPS lamp, producing a
2153:
683:
539:
375:. Later advancements in blue- and green-screen techniques and computer imagery closed that gap, leaving SVP economically impractical.
1677:
709:
565:
1360:"Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility"
1221:
1838:
1456:
2696:
2593:
2331:
2198:
1284:
Luginbuhl, C. B. (12–16 July 1999), "Why
Astronomy Needs Low-Pressure Sodium Lighting", in R. J. Cohen; W. T. Sullivan (eds.),
1154:
1460:
349:. This technique originally yielded results superior to blue-screen technology, and was used in years 1956 to 1990, mostly by
2423:
2208:
1041:
687:
586:/mercury vapour for extra colour rendering is quickly and gradually replaced by the orange glow of the metalic sodium vapour.
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183:
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2218:
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802:
278:
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1749:
637:
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Warm-up phases of a 70W HPS/SON lamp on a DW Windsor Strand B fitting. The faint white glow from the arc struck in the
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clouds. Where sodium vapor lights are the source of urban illumination, the night sky is tinged with orange.
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lighting conditions. Some higher-power lamps (e.g. 600 watt) have efficacies of about 150 lumens per watt.
2278:
2203:
1666:– Corridor Crew via YouTube (2024) – recreating the sodium vapor light system used in film special effects
911:
881:
285:
ratings from 10 to 180 W; longer lamp lengths can, however, suffer design and engineering problems.
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characteristics. In addition, the red wing of the D-line emission is further pressure broadened by the
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of the gas to be relatively low in the cold state, which allows the lamp to be easily started.
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of mercury and sodium, but is dominated by the sodium D-line emission. This line is extremely
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429:
271:
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gas discharge tube (arc tube) and a metal cap. They include the sodium-vapor lamp that is the
82:
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High-pressure sodium lamps are quite efficient—about 100 lumens per watt, when measured for
359:
354:
282:
244:
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In practical use, the lamp is powered by an AC voltage source in series with an inductive "
590:
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2010:
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because of absorption in the cooler outer layers of the arc, giving the lamp its improved
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1993:
1971:
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225:
129:
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2501:
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1966:
1931:
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1825:
1810:
1766:
843:
776:
747:
267:
259:
217:
94:
78:
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235:
LPS lamps have an outer glass vacuum envelope around the inner discharge tube for
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2103:
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1956:
1951:
1936:
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988:
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at a low pressure is used as a "starter gas" in the HPS lamp. It has the lowest
416:
404:
Diagram showing the spectral output of a typical high-pressure sodium (HPS) lamp
383:
1178:"Heads Up! Philips Low Pressure Sodium SOX Bulbs Are Going the Way of the Dodo"
738:
At end of life, high-pressure sodium (HPS) lamps exhibit a phenomenon known as
160:
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2496:
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2343:
2326:
2258:
2253:
2228:
1923:
1655:
1490:. Lighting Research Center, Rensselaer Polytechnic Institute. January 31, 2008
425:
318:
90:
1533:
1200:"End of an era as remaining 70 jobs at former Philips factory are to be axed"
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2526:
2115:
2091:
2020:
2000:
1605:
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837:
229:
188:
63:
17:
1405:
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to use the tradename "Lucalox" for its line of high-pressure sodium lamps.
1623:
152:
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2015:
1976:
1941:
1911:
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751:
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455:
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Since the high-pressure sodium arc is extremely chemically reactive, the
441:
433:
255:
1012:
Revolution in Lamps: A Chronicle of 50 Years of
Progress, Second Edition
81:, where they are widely used. High-pressure sodium lamps emit a broader
38:
2360:
2305:
2005:
1983:
444:
is essential for proper planning when designing lighting for roadways.
437:
971:"Lighting Comparison: LED vs High Pressure Sodium/Low Pressure Sodium"
408:
1988:
1946:
200:
55:
1485:"Mesoptic Street Lighting Demonstration and Evaluation Final Report"
1317:"The impact of light source spectral power distribution on sky glow"
144:
2671:
2035:
1961:
729:
721:
589:
577:
469:
415:
407:
399:
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321:
nesting beaches, low-pressure sodium is preferred (as formerly in
289:
being ineffective, while consuming undiminished electrical power.
208:
182:
174:
166:
159:
151:
143:
59:
37:
29:
85:
of light than the low-pressure lamps, but they still have poorer
1129:
1104:
1054:
828: – Light source using an electric arc through mercury vapor
263:
204:
101:
1673:
1450:"High Pressure Sodium Lamps: A Pacific Energy Center Factsheet"
1079:
89:
than other types of lamps. Low-pressure sodium lamps only give
1227:. City of San José, California. June 20, 2000 . Archived from
655:
511:
124:
Research into high-pressure sodium lamps occurred in both the
1650:
1669:
1321:
1222:"Council policy - outdoor lighting on private developments"
1315:
Luginbuhl, C. B.; Boley, P. A.; Daviws, D. R. (May 2014).
873:
San Jose: Study and report on low-pressure sodium lighting
412:
Office building illuminated by high-pressure sodium lamps
420:
High-pressure sodium lamp
Philips SON-T Master 600 W
353:. Notable examples of films using this technique include
783:
the ballast will make a new series of startup attempts.
258:
lighting conditions, producing above 100 and up to 206
610:
The lamp is operating with liquid amalgam in the tube.
100:
Single ended self-starting lamps are insulated with a
148:
A low-pressure sodium lamp running at full brightness
846: – Raised source of light beside a road or path
274:) where faithful color rendition is not important.
2654:
2609:
2550:
2473:
2389:
2314:
2184:
2124:
2072:
2044:
1922:
1824:
1796:
1787:
1707:
799: – Lamp that produces light by an electric arc
1593:
1421:"Yellow Screen and the Revenge of the Blue Screen"
1036:, Macmillan International Higher Education, 1986,
613:The lamp is operating with all amalgam evaporated.
816: – Excess artificial light in an environment
1287:Why Astronomy Needs Low-Pressure Sodium Lighting
822: – Devices and processes that produce light
1358:Aubé, M.; Roby, J.; Kocifaj, M. (5 July 2013).
809:History of street lighting in the United States
199:gas discharge tube (arc tube) containing solid
1510:"Philips SDW-T High Pressure Sodium White SON"
607:The lamp is extinguished and no current flows.
34:A high-pressure sodium street light in Toronto
1685:
880:: City of San Jose. p. 8. Archived from
62:at a characteristic wavelength near 589
8:
989:"The Sodium Lamp - How It Works and History"
840: – Light source based on gas discharge
690:. Unsourced material may be challenged and
546:. Unsourced material may be challenged and
1793:
1692:
1678:
1670:
1561:de Groot, J J; van Vliet; J A J M (1986).
1395:
1385:
1375:
1342:
1332:
1295:
710:Learn how and when to remove this message
566:Learn how and when to remove this message
220:, the emission becomes the common bright
805: – Type of electric lamp/bulb (HID)
1032:J. J. de Groot, J. A. J. M. van Vliet,
934:
932:
862:
195:Low-pressure sodium (LPS) lamps have a
1006:
1004:
1002:
951:
949:
594:Diagram of a high-pressure sodium lamp
387:High-pressure sodium lamp in operation
1499:(Comparison is with HPS and MH lamps)
7:
1014:, Fairmont Press, 2001. pp. 238–241.
904:"Low-Pressure Sodium Issues and FAQ"
688:adding citations to reliable sources
628:The light from the lamp consists of
544:adding citations to reliable sources
870:Department of Public Works (1980).
648:from the mercury atoms in the arc.
500:of around 2700 kelvins with a
69:Two varieties of such lamps exist:
27:Type of electric gas-discharge lamp
1651:Museum of Electric Discharge Lamps
1210:from the original on Nov 22, 2021.
252:efficient electrical light sources
224:. These lamps produce a virtually
93:yellow light and so inhibit color
25:
1419:Hess, John P. (January 6, 2017).
1304:from the original on Jan 24, 2024
1165:from the original on 24 Jan 2024.
492:"White" high pressure sodium lamp
458:is typically made of translucent
313:is a consideration, such as near
42:A high-pressure sodium-vapor lamp
1457:Pacific Gas and Electric Company
1176:Root, Doug (28 September 2017).
660:
516:
2209:Parabolic aluminized reflector
1569:: Kluwer Technische Boeken BV.
1155:"MASTER SOX-E 131W BY22d 1SL/6"
58:in an excited state to produce
2154:Hydrargyrum medium-arc iodide
957:"The Low Pressure Sodium Lamp"
940:"The Low Pressure Sodium Lamp"
634:pressure (resonance) broadened
305:Light pollution considerations
297:, Scotland factory on December
1:
1563:The High-Pressure Sodium Lamp
1034:The High-Pressure Sodium Lamp
803:High-intensity discharge lamp
250:LPS lamps are among the most
1387:10.1371/journal.pone.0067798
462:. This construction led the
2399:Automotive light bulb types
2249:Intelligent street lighting
1656:This Invention Made Disney
1344:10.1016/j.jqsrt.2013.12.004
171:A running 35 W LPS/SOX lamp
2751:
2162:Hydrargyrum quartz iodide
1459:. May 1997. Archived from
1010:Raymond Kane, Heinz Sell,
600:amalgam of metallic sodium
315:astronomical observatories
247:, resulting in SOX lamps.
156:An unlit 35 W LPS/SOX lamp
2601:Stage lighting instrument
1632:USA patent US3737717A
1592:Waymouth, John F (1971).
726:Sodium vapor street light
2662:Battlefield illumination
2419:high-intensity discharge
1851:Electrochemiluminescence
1596:Electric Discharge Lamps
902:Luginbuhl, Christian B.
464:General Electric Company
372:Bedknobs and Broomsticks
279:High-intensity discharge
228:light averaging a 589.3
104:disc and contained in a
2522:Electroluminescent wire
1253:"Flagstaff Zoning Code"
852: – Lighting system
2204:Multifaceted reflector
1161:. September 19, 2023.
912:U.S. Naval Observatory
735:
727:
595:
587:
421:
413:
405:
397:
388:
203:and a small amount of
192:
180:
172:
164:
157:
149:
43:
35:
2594:ellipsoidal reflector
2199:Ellipsoidal reflector
1883:Fluorescent induction
1861:field-induced polymer
1182:AtlantaLightBulbs.com
820:List of light sources
733:
725:
630:atomic emission lines
593:
581:
502:color rendering index
419:
411:
403:
394:
386:
363:and the Disney films
186:
178:
170:
163:
155:
147:
41:
33:
2431:Rear position lights
2404:Daytime running lamp
2332:Mechanically powered
2219:Aviation obstruction
1265:on 13 September 2014
993:EdisonTechCenter.org
834: – Type of lamp
684:improve this section
646:Van der Waals forces
540:improve this section
478:ionization potential
474:thermal conductivity
379:High-pressure sodium
343:Sodium vapor process
338:Film special effects
323:San Jose, California
309:For locations where
112:in street lighting.
2720:Gas discharge lamps
1839:Electron-stimulated
1377:2013PLoSO...867798A
1334:2014JQSRT.139...21L
1297:2001IAUS..196...81L
508:Theory of operation
396:arise from mercury.
140:Low-pressure sodium
2682:Luminous gemstones
1856:Electroluminescent
1834:Cathodoluminescent
975:StouchLighting.com
908:Flagstaff, Arizona
826:Mercury-vapor lamp
736:
734:Closeup after dark
728:
596:
588:
480:of all the stable
422:
414:
406:
398:
389:
327:Flagstaff, Arizona
237:thermal insulation
197:borosilicate glass
193:
181:
173:
165:
158:
150:
110:gas-discharge lamp
106:borosilicate glass
52:gas-discharge lamp
44:
36:
2707:
2706:
2224:Balanced-arm lamp
2180:
2179:
2064:Yablochkov candle
1932:Acetylene/Carbide
1902:Radioluminescence
1774:Luminous efficacy
1720:Color temperature
1615:978-0-262-23048-3
1576:978-90-201-1902-2
832:Metal-halide lamp
720:
719:
712:
576:
575:
568:
498:color temperature
486:breakdown voltage
426:plant grow lights
272:security lighting
254:when measured in
48:sodium-vapor lamp
16:(Redirected from
2742:
2507:Christmas lights
2441:Safety reflector
2436:Reversing lights
2371:Navigation light
2322:Bicycle lighting
2212:
2165:
2157:
2131:
1890:Photoluminescent
1873:Fluorescent lamp
1846:Chemiluminescent
1794:
1762:Bi-pin lamp base
1757:Lightbulb socket
1694:
1687:
1680:
1671:
1660:, but Then They
1640:
1639:
1635:
1627:
1599:
1588:
1548:
1547:
1545:
1544:
1530:
1524:
1523:
1521:
1520:
1506:
1500:
1498:
1496:
1495:
1489:
1481:
1475:
1474:
1472:
1471:
1465:
1454:
1446:
1440:
1439:
1437:
1436:
1427:. Archived from
1416:
1410:
1409:
1399:
1389:
1379:
1355:
1349:
1348:
1346:
1336:
1312:
1306:
1305:
1299:
1281:
1275:
1274:
1272:
1270:
1264:
1258:. Archived from
1257:
1249:
1243:
1242:
1240:
1239:
1233:
1226:
1218:
1212:
1211:
1206:. 11 July 2019.
1196:
1190:
1189:
1188:on May 23, 2022.
1184:. Archived from
1173:
1167:
1166:
1159:Philips lighting
1151:
1145:
1144:
1142:
1141:
1126:
1120:
1119:
1117:
1116:
1101:
1095:
1094:
1092:
1091:
1076:
1070:
1069:
1067:
1066:
1051:
1045:
1030:
1024:
1021:
1015:
1008:
997:
996:
985:
979:
978:
967:
961:
960:
953:
944:
943:
936:
927:
926:
924:
923:
914:. Archived from
899:
893:
892:
890:
889:
867:
715:
708:
704:
701:
695:
664:
656:
571:
564:
560:
557:
551:
520:
512:
355:Alfred Hitchcock
300:
245:indium tin oxide
21:
2750:
2749:
2745:
2744:
2743:
2741:
2740:
2739:
2735:Street lighting
2725:Light pollution
2710:
2709:
2708:
2703:
2667:Bioluminescence
2650:
2619:
2605:
2562:
2546:
2485:
2469:
2385:
2310:
2234:Emergency light
2210:
2176:
2163:
2155:
2129:
2127:
2120:
2068:
2040:
2011:Magnesium torch
1918:
1820:
1789:
1783:
1740:Light pollution
1715:Accent lighting
1703:
1698:
1647:
1637:
1630:
1616:
1591:
1577:
1560:
1557:
1552:
1551:
1542:
1540:
1532:
1531:
1527:
1518:
1516:
1508:
1507:
1503:
1493:
1491:
1487:
1483:
1482:
1478:
1469:
1467:
1463:
1452:
1448:
1447:
1443:
1434:
1432:
1418:
1417:
1413:
1357:
1356:
1352:
1314:
1313:
1309:
1283:
1282:
1278:
1268:
1266:
1262:
1255:
1251:
1250:
1246:
1237:
1235:
1231:
1224:
1220:
1219:
1215:
1198:
1197:
1193:
1175:
1174:
1170:
1153:
1152:
1148:
1139:
1137:
1128:
1127:
1123:
1114:
1112:
1103:
1102:
1098:
1089:
1087:
1078:
1077:
1073:
1064:
1062:
1053:
1052:
1048:
1031:
1027:
1022:
1018:
1009:
1000:
987:
986:
982:
969:
968:
964:
955:
954:
947:
938:
937:
930:
921:
919:
901:
900:
896:
887:
885:
869:
868:
864:
859:
814:Light pollution
793:
769:
765:
761:
716:
705:
699:
696:
681:
665:
654:
642:color rendering
572:
561:
555:
552:
537:
521:
510:
494:
428:. They contain
381:
340:
311:light pollution
307:
298:
213:Penning mixture
142:
118:
95:vision at night
87:color rendering
28:
23:
22:
15:
12:
11:
5:
2748:
2746:
2738:
2737:
2732:
2727:
2722:
2712:
2711:
2705:
2704:
2702:
2701:
2700:
2699:
2689:
2684:
2679:
2674:
2669:
2664:
2658:
2656:
2655:Related topics
2652:
2651:
2649:
2648:
2643:
2638:
2633:
2628:
2622:
2620:
2618:
2617:
2614:
2610:
2607:
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2598:
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2581:
2576:
2571:
2565:
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2557:
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2539:
2534:
2529:
2524:
2519:
2514:
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2484:
2483:
2478:
2474:
2471:
2470:
2468:
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2466:
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2455:
2450:
2449:
2448:
2446:retroreflector
2438:
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2416:
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2340:
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2334:
2324:
2318:
2316:
2312:
2311:
2309:
2308:
2303:
2301:Track lighting
2298:
2293:
2292:
2291:
2281:
2276:
2274:Recessed light
2271:
2266:
2261:
2256:
2251:
2246:
2244:Gooseneck lamp
2241:
2236:
2231:
2226:
2221:
2216:
2215:
2214:
2206:
2201:
2190:
2188:
2182:
2181:
2178:
2177:
2175:
2174:
2169:
2168:
2167:
2159:
2151:
2141:
2135:
2133:
2126:High-intensity
2122:
2121:
2119:
2118:
2113:
2108:
2107:
2106:
2096:
2095:
2094:
2084:
2078:
2076:
2070:
2069:
2067:
2066:
2061:
2056:
2050:
2048:
2042:
2041:
2039:
2038:
2033:
2028:
2023:
2018:
2013:
2008:
2003:
1998:
1997:
1996:
1991:
1981:
1980:
1979:
1969:
1964:
1959:
1954:
1949:
1944:
1939:
1934:
1928:
1926:
1920:
1919:
1917:
1916:
1915:
1914:
1904:
1899:
1898:
1897:
1895:Laser headlamp
1887:
1886:
1885:
1880:
1865:
1864:
1863:
1853:
1848:
1843:
1842:
1841:
1830:
1828:
1822:
1821:
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1791:
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1776:
1771:
1770:
1769:
1764:
1754:
1753:
1752:
1747:
1737:
1732:
1727:
1725:Electric light
1722:
1717:
1711:
1709:
1705:
1704:
1699:
1697:
1696:
1689:
1682:
1674:
1668:
1667:
1653:
1646:
1645:External links
1643:
1642:
1641:
1628:
1614:
1589:
1575:
1556:
1553:
1550:
1549:
1525:
1514:LampTech.co.uk
1501:
1476:
1441:
1411:
1350:
1307:
1276:
1244:
1213:
1191:
1168:
1146:
1134:LampTech.co.uk
1121:
1111:. Jun 16, 2015
1109:LampTech.co.uk
1105:"SOI/H Sodium"
1096:
1084:LampTech.co.uk
1071:
1061:. Jun 11, 2018
1059:LampTech.co.uk
1055:"SLI/H Sodium"
1046:
1025:
1016:
998:
980:
962:
945:
928:
894:
861:
860:
858:
855:
854:
853:
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835:
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718:
717:
668:
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659:
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650:
615:
614:
611:
608:
574:
573:
524:
522:
515:
509:
506:
493:
490:
460:aluminum oxide
380:
377:
351:Disney Studios
339:
336:
331:Purkinje shift
306:
303:
141:
138:
126:United Kingdom
117:
114:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
2747:
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2715:
2698:
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2668:
2665:
2663:
2660:
2659:
2657:
2653:
2647:
2644:
2642:
2639:
2637:
2636:Infrared lamp
2634:
2632:
2629:
2627:
2624:
2623:
2621:
2615:
2612:
2611:
2608:
2602:
2599:
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2392:
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2379:
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2369:
2367:
2366:Laser pointer
2364:
2362:
2359:
2355:
2352:
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2347:
2345:
2342:
2338:
2335:
2333:
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2320:
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2313:
2307:
2304:
2302:
2299:
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2294:
2290:
2287:
2286:
2285:
2282:
2280:
2277:
2275:
2272:
2270:
2269:Pendant light
2267:
2265:
2264:Neon lighting
2262:
2260:
2257:
2255:
2252:
2250:
2247:
2245:
2242:
2240:
2237:
2235:
2232:
2230:
2227:
2225:
2222:
2220:
2217:
2213:
2207:
2205:
2202:
2200:
2197:
2196:
2195:
2192:
2191:
2189:
2187:
2183:
2173:
2170:
2166:
2160:
2158:
2152:
2150:
2147:
2146:
2145:
2142:
2140:
2139:Mercury-vapor
2137:
2136:
2134:
2132:
2123:
2117:
2114:
2112:
2109:
2105:
2102:
2101:
2100:
2097:
2093:
2090:
2089:
2088:
2085:
2083:
2082:Deuterium arc
2080:
2079:
2077:
2075:
2074:Gas discharge
2071:
2065:
2062:
2060:
2057:
2055:
2052:
2051:
2049:
2047:
2043:
2037:
2034:
2032:
2029:
2027:
2024:
2022:
2019:
2017:
2014:
2012:
2009:
2007:
2004:
2002:
1999:
1995:
1992:
1990:
1987:
1986:
1985:
1982:
1978:
1975:
1974:
1973:
1970:
1968:
1965:
1963:
1960:
1958:
1955:
1953:
1950:
1948:
1945:
1943:
1940:
1938:
1935:
1933:
1930:
1929:
1927:
1925:
1921:
1913:
1910:
1909:
1908:
1905:
1903:
1900:
1896:
1893:
1892:
1891:
1888:
1884:
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1878:
1874:
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1869:
1866:
1862:
1859:
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1857:
1854:
1852:
1849:
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1837:
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1832:
1831:
1829:
1827:
1823:
1817:
1814:
1812:
1809:
1807:
1804:
1803:
1801:
1799:
1795:
1792:
1786:
1780:
1779:Task lighting
1777:
1775:
1772:
1768:
1765:
1763:
1760:
1759:
1758:
1755:
1751:
1748:
1746:
1743:
1742:
1741:
1738:
1736:
1735:Light fixture
1733:
1731:
1728:
1726:
1723:
1721:
1718:
1716:
1713:
1712:
1710:
1706:
1702:
1695:
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1672:
1665:
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1652:
1649:
1648:
1644:
1633:
1629:
1625:
1621:
1617:
1611:
1607:
1603:
1602:Cambridge, MA
1598:
1597:
1590:
1586:
1582:
1578:
1572:
1568:
1564:
1559:
1558:
1554:
1539:
1535:
1529:
1526:
1515:
1511:
1505:
1502:
1486:
1480:
1477:
1466:on 2022-03-30
1462:
1458:
1451:
1445:
1442:
1431:on 2018-11-28
1430:
1426:
1422:
1415:
1412:
1407:
1403:
1398:
1393:
1388:
1383:
1378:
1373:
1370:(7): e67798.
1369:
1365:
1361:
1354:
1351:
1345:
1340:
1335:
1330:
1326:
1322:
1318:
1311:
1308:
1303:
1298:
1293:
1289:
1288:
1280:
1277:
1261:
1254:
1248:
1245:
1234:on 2012-05-15
1230:
1223:
1217:
1214:
1209:
1205:
1201:
1195:
1192:
1187:
1183:
1179:
1172:
1169:
1164:
1160:
1156:
1150:
1147:
1136:. Nov 2, 2015
1135:
1131:
1125:
1122:
1110:
1106:
1100:
1097:
1086:. Jun 4, 2015
1085:
1081:
1080:"SO/H Sodium"
1075:
1072:
1060:
1056:
1050:
1047:
1043:
1039:
1035:
1029:
1026:
1020:
1017:
1013:
1007:
1005:
1003:
999:
994:
990:
984:
981:
976:
972:
966:
963:
958:
952:
950:
946:
941:
935:
933:
929:
918:on 2015-09-10
917:
913:
909:
905:
898:
895:
884:on 2016-03-04
883:
879:
875:
874:
866:
863:
856:
851:
848:
845:
842:
839:
836:
833:
830:
827:
824:
821:
818:
815:
812:
810:
807:
804:
801:
798:
795:
794:
790:
788:
784:
780:
778:
777:arc discharge
757:
756:
755:
753:
749:
745:
741:
732:
724:
714:
711:
703:
700:December 2017
693:
689:
685:
679:
678:
674:
669:This section
667:
663:
658:
657:
651:
649:
647:
643:
639:
638:self-reversed
635:
631:
626:
624:
619:
612:
609:
606:
605:
604:
601:
592:
585:
580:
570:
567:
559:
556:December 2017
549:
545:
541:
535:
534:
530:
525:This section
523:
519:
514:
513:
507:
505:
503:
499:
491:
489:
487:
483:
479:
475:
471:
467:
465:
461:
457:
452:
450:
445:
443:
439:
435:
431:
427:
418:
410:
402:
393:
385:
378:
376:
374:
373:
368:
367:
362:
361:
356:
352:
348:
344:
337:
335:
332:
328:
324:
320:
316:
312:
304:
302:
296:
290:
286:
284:
280:
275:
273:
269:
268:street lights
265:
261:
257:
253:
248:
246:
242:
238:
233:
231:
227:
226:monochromatic
223:
219:
214:
210:
206:
202:
198:
190:
185:
177:
169:
162:
154:
146:
139:
137:
133:
131:
130:United States
127:
122:
115:
113:
111:
107:
103:
98:
96:
92:
91:monochromatic
88:
84:
80:
76:
75:high pressure
72:
67:
65:
61:
57:
53:
49:
40:
32:
19:
2542:Strobe light
2537:Plasma globe
2512:Crackle tube
2502:Bubble light
2463:trafficators
2458:Turn signals
2284:Street light
2239:Gas lighting
2172:Sodium vapor
2171:
2144:Metal-halide
2046:Electric arc
1798:Incandescent
1767:Edison screw
1661:
1657:
1595:
1562:
1541:. Retrieved
1537:
1528:
1517:. Retrieved
1513:
1504:
1492:. Retrieved
1479:
1468:. Retrieved
1461:the original
1444:
1433:. Retrieved
1429:the original
1425:Filmmaker IQ
1424:
1414:
1367:
1363:
1353:
1324:
1320:
1310:
1286:
1279:
1267:. Retrieved
1260:the original
1247:
1236:. Retrieved
1229:the original
1216:
1204:Daily Record
1203:
1194:
1186:the original
1181:
1171:
1158:
1149:
1138:. Retrieved
1133:
1130:"SOX Sodium"
1124:
1113:. Retrieved
1108:
1099:
1088:. Retrieved
1083:
1074:
1063:. Retrieved
1058:
1049:
1044:. pp. 13-17.
1033:
1028:
1019:
1011:
992:
983:
974:
965:
920:. Retrieved
916:the original
897:
886:. Retrieved
882:the original
872:
865:
844:Street light
785:
781:
773:
748:sodium oxide
739:
737:
706:
697:
682:Please help
670:
636:and is also
627:
620:
616:
597:
562:
553:
538:Please help
526:
495:
468:
453:
446:
423:
370:
366:Mary Poppins
364:
358:
341:
308:
291:
287:
276:
249:
234:
194:
134:
123:
119:
99:
79:street lamps
74:
71:low pressure
70:
68:
47:
45:
18:Sodium vapor
2687:Signal lamp
2641:Stroboscope
2517:DJ lighting
2453:Stop lights
2424:sealed beam
2376:Searchlight
2116:Xenon flash
2059:Klieg light
1907:Solid-state
1868:Fluorescent
1826:Luminescent
850:Sulfur lamp
652:End of life
482:noble gases
476:and lowest
116:Development
2714:Categories
2631:Grow light
2626:Germicidal
2616:Scientific
2613:Industrial
2569:Floodlight
2555:Theatrical
2497:Blacklight
2492:Aroma lamp
2481:Decorative
2391:Automotive
2381:Solar lamp
2344:Glow stick
2327:Flashlight
2259:Nightlight
2254:Light tube
2229:Chandelier
2186:Stationary
2128:discharge
2054:Carbon arc
1924:Combustion
1790:generation
1788:Methods of
1543:2024-08-03
1538:DW Windsor
1519:2007-09-24
1494:2011-08-29
1470:2024-07-24
1435:2019-09-08
1238:2012-10-14
1140:2012-03-03
1115:2012-03-03
1090:2012-03-03
1065:2012-03-03
1042:1349091960
922:2013-12-05
888:2013-12-06
857:References
347:background
319:sea turtle
301:31, 2019.
241:reflecting
189:Honda Fits
54:that uses
2697:Reflected
2677:Light art
2589:Spotlight
2574:Footlight
2559:Cinematic
2527:Lava lamp
2289:in the US
2194:Reflector
2111:Xenon arc
2092:Neon lamp
2021:Rushlight
2001:Limelight
1750:Hong Kong
1606:MIT Press
1327:: 21–26.
838:Neon lamp
758:6 Na + Al
671:does not
527:does not
360:The Birds
243:layer of
218:vaporizes
211:gas in a
2409:Headlamp
2349:Headlamp
2337:Tactical
2315:Portable
2296:Torchère
1977:Petromax
1972:Kerosene
1942:Campfire
1912:LED lamp
1708:Concepts
1701:Lighting
1658:Millions
1585:16637733
1567:Deventer
1534:"Strand"
1406:23861808
1364:PLOS ONE
1302:archived
1269:14 April
1208:Archived
1163:Archived
878:San Jose
797:Arc lamp
791:See also
770:O + 2 Al
752:aluminum
744:products
584:Arc tube
456:arc tube
449:photopic
442:scotopic
434:photopic
295:Hamilton
256:photopic
128:and the
83:spectrum
2692:Sources
2646:Tanning
2532:Marquee
2477:Display
2361:Lantern
2354:outdoor
2306:Troffer
2149:ceramic
2006:Luchina
1984:Lantern
1877:compact
1875: (
1811:Halogen
1806:Regular
1555:Sources
1397:3702543
1372:Bibcode
1329:Bibcode
1292:Bibcode
740:cycling
692:removed
677:sources
623:ballast
548:removed
533:sources
438:mesopic
430:mercury
2730:Sodium
2414:hidden
2279:Sconce
2104:Sulfur
2099:Plasma
2031:Tilley
2026:Safety
1989:Fanous
1952:Carcel
1947:Candle
1937:Argand
1816:Nernst
1745:Hawaii
1638:
1624:214331
1622:
1612:
1583:
1573:
1404:
1394:
1040:
766:→ 3 Na
299:
222:yellow
201:sodium
56:sodium
2672:Laser
2584:Scoop
2211:(PAR)
2164:(HQI)
2156:(HMI)
2130:(HID)
2036:Torch
1994:Paper
1962:Flare
1730:Glare
1488:(PDF)
1464:(PDF)
1453:(PDF)
1263:(PDF)
1256:(PDF)
1232:(PDF)
1225:(PDF)
470:Xenon
283:power
209:argon
60:light
50:is a
2579:Gobo
2087:Neon
1957:Diya
1662:Lost
1620:OCLC
1610:ISBN
1581:OCLC
1571:ISBN
1402:PMID
1271:2014
1038:ISBN
750:and
746:are
675:any
673:cite
531:any
529:cite
440:and
369:and
325:and
270:and
207:and
205:neon
187:Two
102:mica
73:and
2016:Oil
1967:Gas
1664:It!
1392:PMC
1382:doi
1339:doi
1325:139
686:by
598:An
542:by
436:to
357:'s
317:or
2716::
1618:.
1608:.
1604::
1600:.
1579:.
1565:.
1536:.
1512:.
1455:.
1423:.
1400:.
1390:.
1380:.
1366:.
1362:.
1337:.
1323:.
1319:.
1300:,
1202:.
1180:.
1157:.
1132:.
1107:.
1082:.
1057:.
1001:^
991:.
973:.
948:^
931:^
910::
906:.
876:.
754::
260:lm
230:nm
97:.
66:.
64:nm
46:A
1879:)
1693:e
1686:t
1679:v
1626:.
1587:.
1546:.
1522:.
1497:.
1473:.
1438:.
1408:.
1384::
1374::
1368:8
1347:.
1341::
1331::
1294::
1273:.
1241:.
1143:.
1118:.
1093:.
1068:.
995:.
977:.
959:.
942:.
925:.
891:.
768:2
764:3
762:O
760:2
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707:(
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694:.
680:.
569:)
563:(
558:)
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550:.
536:.
264:W
262:/
20:)
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