Here is a great article about the development of artificial lighting. The authors are:
LIISA HALONEN, Doctor of Technology, Professor
liisa.halonen@hut.fi
MARJUKKA ELOHOLMA, Doctor of Technology, Researcher
Helmet University of Technology, Lighting Laboratory
Otakaari 5, 02015 TKK
Light has always had great significance for humans. Light has been vital in human everyday activities, and it has enabled a wide range of activities. The history of electric light is short compared to the entire history of artificial light, but electric light has had a major impact on social and industrial development.
When ancient man learned to make fire, he also became the first to use artificial lighting. In addition to cooking and heating, the fireplace was also a source of light for ancient people. Fire gave people a little freedom from the darkness of the night and protection from invisible nocturnal beasts. Over time, it was discovered that resinous trees give a brighter light in a fireplace. The next step was to collect the resin on the end of a wooden stick and tie several wooden sticks together, creating a torch, with the wooden stick serving only as a handle. The first portable lamp had been developed.
Prehistoric people used primitive lamps to light their caves. These lamps were made from available materials such as stone, shells and horns, and were filled with fat. Hundreds of such lamps have been found in the famous Lascaux caves in France, estimated to be around 17,000 years old.
In the Middle Ages, the oil lamp was improved, and Leonardo da Vinci also played a part in the development work. Leonardo was not only an artist but also a scientist. He studied, among other things, the nature of light, reflection and refraction. In 1480, he invented the idea of making a chimney over the flame of an oil lamp, which increased the draft and brightened the flame. In the Middle Ages, a unique oil lamp was used in Finland, with a hollowed-out turnip as the container and a linen braid as the heart, and hemp oil as the fuel. Such turnip lamps were still widely used in our country's rectories in the 18th century.
As urban culture developed, concerns arose about the safety of those walking on the streets at night. In European cities, nighttime travelers carried oil lanterns with them in the 17th century. In Paris, the first steps towards street lighting were taken after the 1650s, when oil lanterns were placed at both ends of short streets. On longer streets, lanterns were also placed in the middle. In Berlin, an order was issued that every third house resident had to place a lantern that burned at night outside their house and that the lantern had to be maintained together with the neighbors. The first lights on the streets of Helsinki were oil lanterns, which were put into use in 1818. History tells us that these oil lanterns mainly illuminated themselves and not so much the streets. Therefore, people walked the streets in the dark with portable oil lanterns.
One development in the history of the oil lamp was the invention of a new fuel, kerosene, in 1859. At first, these kerosene lamps were dangerous, as crude kerosene contained gasoline, which could easily explode the entire lamp. With distillation, this problem was eliminated and the kerosene lamp quickly became more common in domestic use.
The candle was invented around 400 AD, possibly a little earlier. Before the 14th century, candles were not widely used in homes, but they played an important role in churches, for example. The best candles were made from beeswax and were used in church rituals, because the bee was considered a symbol of purity. Since then, the use of candles has become more common. Before stearin candles, wax and tallow candles were used. Candles from the late 16th century required watchkeeping, which is known to have caused annoyance to, among others, the writer Shakespeare of the time. In a performance of one of Shakespeare's plays, the assistants were responsible for looking after the candles burning on stage so that the flame would not start to smoke. In order to keep the candlelight bright, the assistants had to constantly walk across the stage, even during the most intense moments of the drama, which is known to have caused artistic annoyance to Shakespeare, who was watching the performance.
Later, people learned how to make candles that were easier to maintain and of more consistent quality. In 1823, they learned how to make candles from stearin that no longer dripped. Whale oil, on the other hand, produced candles of particularly consistent quality, which were also used as a standard for measuring light in the 1860s.
The use of gas for lighting began in Europe in the 19th century, when the gas lamp powered by coal gas was introduced alongside oil and kerosene lamps. However, the invention was not new, as the Chinese knew how to use natural gas for lighting hundreds of years before the beginning of our era.
The spread of gas lighting in Europe was closely linked to urbanisation and industrialisation. In Europe, the first permanent gas lighting was installed in the industrial centre of Birmingham in 1802. London had around 40,000 gas lamps in street lighting by 1823. The advantage of gas lighting was its ease of use. Gas lighting also came with its risks, which was the fate of several theatre buildings. Theatres needed light, and the use of gas for lighting was the first real step forward in theatre lighting. Covent Garden in England had gas lighting as early as 1817. The Haymarket was the last theatre in London to switch to gas lighting in 1843, when candles and oil lamps made way for this new lighting method. Among the theatres in New York, the Bowery Theatre was one of the few to have experienced setbacks with gas lighting. It burned down no fewer than nine times before being demolished in 1930. It is reported that several hundred theaters in Europe and the United States burned down as a result of the careless use of gaslight.
Gas lanterns, which provided better lighting than oil lanterns, also appeared on the streets of Helsinki in the 1860s. The last gas lanterns were removed from Helsinki in 1946.
The introduction of electricity into lighting can be said to have begun as early as the end of the 17th century, although only at the stage of the discovery of the phenomenon. At that time, the German von Guericke discovered that when a sulfur ball was rubbed, electricity caused weak light phenomena. Hauskbee, in turn, noticed that a glass ball filled with rarefied air began to glow when rubbed electrically. Although the invention was significant, it was of no practical importance, as the ball had to be constantly rubbed to maintain the light.
On the way to the invention of the incandescent lamp, another significant lighting invention related to electricity was made. In 1809, the Englishman Davy received the Napoleon Prize for the best electrical invention of the year. The electric arc had been invented: a bright light-emitting area was created between the carbon tips connected to the terminals of a battery when the tips were at the appropriate distance from each other. However, an attendant was constantly needed to adjust the distance between the carbon tips, so this invention did not yet bring practical solutions to electric lighting.
The Russian Jablochkoff built a usable arc lamp in Paris in 1876. In this so-called Jablochkoff candle, the carbons of the arc lamp were side by side, insulated from each other, and since both rods shortened equally quickly, no regulator or regulating device was needed. When several of these candle lamps were connected in succession, a bright light source was obtained. This is how department stores in Paris are known to have been lit in this way in 1877. This light source could not be considered for homes because of its great brightness. Another disadvantage was its poor usability: one candle only burned for about an hour and a half.
An interesting application for the arc lamp was the idea of using it in city lighting in the 1880s. The idea, which still seems fantastic today, was to use a bright arc lamp to illuminate an entire city by placing one or more "artificial suns" high above the city's rooftops. This idea was tried in many cities in the United States.
The French electrical engineer Sébillot travelled to America and got a “brilliant” idea for lighting Paris. Together with the architect Bourdais, he designed a 360 m high tower that could illuminate the whole of Paris within a radius of five and a half kilometres with a single light source from the top of the tower. The gentlemen submitted their plan to the monument competition announced for the 1889 Paris World Exhibition under the name Colonne-Soleil, the Great Tower of the Sun. Parallel uses were also planned for this incredibly tall tower; its upper platform would have had a viewing platform for a thousand tourists and the tower would have had rooms for those in need of air therapy. Only two proposals were submitted to the monument competition for the World Exhibition, and the Solar Tower came in second place. The victory went to bridge engineer Gustaf Eiffel with his own tower proposal. What would have been the symbol and landmark of Paris if the competition had gone differently? The competition jury justified the decision in favor of the Eiffel Tower by saying that one solar tower would not be enough as the city grew, and that a tall tower would also be a target for terrorists, who were already feared in the late 19th century.
The incandescent lamp was officially invented in the late 19th century. However, by the 1850s, development work on the incandescent lamp and the technologies required for it was already underway around the world. Between 1840 and 1878, several inventions were reported, but none of them led to practical solutions.
American Thomas Alva Edison is remembered in history as the inventor of the incandescent light bulb. Canadians Henry Woodward and Matthew Evans were not so lucky, as they patented the incandescent light bulb in 1875, but unfortunately they did not have the funding to commercialize their invention. In fact, Edison bought the rights to this patent, and after his development, he then introduced the first commercially viable incandescent light bulb on October 21, 1879.
Edison was not only a prolific inventor but also a talented public relations man who understood the importance of publicity and financial support in commercialization. In 1878, his friend, patent attorney Lowrey, helped raise $300,000 in capital from investors to support Edison's work. The same year, the Edison Electric Light Company was founded. Edison played a major role in the widespread use of electricity and electric lighting. He realized that a light bulb alone was not enough, but only the efficient distribution of electrical energy would ensure the success of the incandescent light bulb. Edison designed various components for the generation and distribution of electricity and the introduction of electric lighting.
On New Year's Eve 1879, there were moments of awe and wonder when Edison organized the first public demonstration of his new invention: the streets of Menlo Park, New Jersey, the train station, and Edison's laboratory were illuminated with a hundred incandescent bulbs. Special trains transported crowds of people to admire this miracle.
The English, on the other hand, consider Sir Joseph Swan to be the inventor of the incandescent lamp. Swan had been working on various problems related to the practical manufacture of the incandescent lamp for 30 years. Swan is credited with the invention of the incandescent lamp on December 18, 1878, a year before Edison introduced his first commercial lamp. Just over a month after Edison introduced his first lamp, Swan had to introduce a working carbon filament incandescent lamp in England on February 3, 1879, to prove his invention again. However, Swan did not have the wealth or the PR skills needed to start mass production of the lamp. Although Edison had been granted a patent for the incandescent lamp in England, Edison and Swan later settled their patent dispute and established a joint company in England.
The incandescent lamp became widely known in Europe at the Paris World Exhibition in 1881. Compared to previous lighting methods, the incandescent lamp's superior features were its ease of maintenance and suitability for home use.
Finland was one of the pioneer countries in Europe in the introduction of electric lighting. This was significantly influenced by the fact that Carl von Nottbeck, the son of Finlayson's director Wilhelm von Nottbeck, worked at the Edison factory in the United States at the turn of the 1870s and 1880s. Carl von Nottbeck made an agreement with Edison, according to which he set out to attempt to build a plant similar to the first electric plant to be built in New York in the far North, at the Finlayson factory in Tampere. In Finland, the skeptics of electric lighting were overshadowed when 150 incandescent lamps were lit in the factory's weaving hall on March 15, 1882. All the installation materials were manufactured in the carpentry workshop of the Finlayson factory, where lamp holders, installation strips and other necessary electrical accessories were made from wood. Issue 6 of the Edison Company's newsletter states that Edison received a cable telegram on March 17, 1882, regarding the lights being turned on: "Lighting installed at 61st latitude. A complete success."
Edison's incandescent lamps had been lit in only four places in Europe before Finlayson's factory, all at the turn of 1881 and 1882, just a few months earlier.
A completely different type of light production method compared to the heating of an incandescent filament is a gas discharge. As the temperature of a gas in a closed space increases, radiation characteristic of each gas compound is produced. The goals in the development of discharge lamps have been higher luminous efficiency, longer burning life and alternative color properties of the light compared to incandescent lamps.
Right at the dawn of the new century, in 1901, the inventor Hewitt introduced a discharge lamp based on mercury vapor. The gas was enclosed in a glass tube about 1.2 m long and the light produced was blue-green in color. In 1934, a similar type of lamp was developed based on this, which could produce light with greater power in a smaller space. Mercury lamps are still used, for example, in street lighting, but they have since been partially replaced by discharge lamps that produce more light efficiently.
Mercury vapor lamps were the forerunners of fluorescent lamps. When it was known that mercury vapor emits a lot of invisible ultraviolet radiation, it was invented to coat the walls of the discharge tube with a fluorescent substance that would convert the ultraviolet radiation hitting it into visible light. Fluorescent lamps were first introduced to the public in 1937 at the New York World's Fair. They began to become more common in the 1940s, and the first fluorescent lamps were introduced in Finland in 1941. The introduction of fluorescent lamps can be considered a turning point in the history of electric lighting. When the luminous efficiency of the lamps was increased, the burning life was extended, and the color properties of the lamps were diversified, electric light could even partially replace daylight.
The development of the sodium vapor discharge lamp began in the 1920s, when the first lamps based on low-pressure sodium discharge were manufactured. The radiation produced at low sodium vapor pressure is monochromatic and has a characteristic orange-yellow color. Due to the monochromaticity of the radiation, there is no color reproduction, but the absolute advantage is the high luminous efficacy of the lamp. The luminous efficacy of current low-pressure sodium lamps is up to 200 lm/W.
As the pressure of the sodium vapor increases, the spectrum of the light generated by the discharge broadens and the yellowness decreases. The development of high-pressure sodium lamps began in the 1950s. The first such lamps came onto the market in 1965. The lamps have good properties including high luminous efficacy; currently it is around 140 lm/W. Low-pressure sodium lamps are large in size and are mainly used for road lighting. High-pressure sodium lamps are also used in road and street lighting and, in addition, for example, in outdoor and industrial lighting.
A special type of discharge lamp are metal halide lamps, which use different metal compounds in their discharge tube. Their light contains radiation characteristic of each metal halide compound. Metal halide lamps came onto the market in the 1960s. Today, there are several different types available, with different light output and color properties.
The effect of light on vision has been largely described and modeled using the cone and rod cells of the retina. In 1722, the Dutchman Antony van Leeuwenhoek made the first observations of these cells. In 1834, the German Gottfried Treviranus confirmed that these are »photosensitive receptors.« The so-called diurnal spectral sensitivity function, published by the International Illumination Organization CIE in 1924, has also been largely explained as a curve describing the wavelength response of cone cells.
For over 150 years, it was believed that rods and cones were the only photoreceptor cells in the human eye. However, in 2002, a US research team made a groundbreaking discovery: they discovered a third type of photoreceptor in the mammalian retina. This receptor is considered a missing link that helps describe the mechanisms of the biological effects caused by light. It is believed that the effects of light extend far beyond vision. Biological effects mean that good lighting can have positive effects on human health, well-being, alertness and sleep quality (Leppämäki, this issue). Like the light sensitivity of rod and cone cells, the sensitivity of the third type of photoreceptor also varies with the wavelength of light. However, the maximum sensitivity to the biological effects of light is in a different wavelength range than the maximum spectral sensitivity of vision, which is believed to have significant implications in the future for determining healthy lighting.
A review of the history of artificial lighting written in 2005 cannot fail to end with LEDs (light emitting diodes). These semiconductor components were developed in the 1960s, but significant investment in their development for lighting needs has only been made since the 1990s. The advantages of LEDs in the light source market are their small size, long burning life, luminous efficiency (which is constantly increasing), durability, and the ability to adjust the intensity and color of light.
LEDs offer completely new ways of implementing lighting, and they are predicted to revolutionize lighting practice in the coming years. When Edison began developing the incandescent lamp in the 1870s to replace the arc lamp lighting of the time, he is said to have stated when he saw a light source based on eight arc lamps: »I saw that what had been done was not yet practically useful. Bright light had not been divided into parts so that it could be brought into private homes.« It is true that the incandescent lamp became an excellent light source for homes, and it revolutionized its time. Now, more than a century after Edison's invention, when small LEDs are making their way into general lighting, we may be on the verge of another step: light sources can be divided into parts so that light is brought in small units, for example, integrated into furniture, to where it is needed in various functions in homes, workplaces and traffic.
The journey of light and humans has come a long way, from cavemen's campfires to LED lighting that changes color and intensity. The journey continues, as research and development work is being carried out on both light sources and more efficient and human-friendly lighting methods.
Light is also believed to have biological effects on humans that we do not yet know about. The latest research area is the combination of lighting and brain research in an effort to investigate the physical and biological effects of light on human vision, function and health. The Lighting Laboratory of the Helsinki University of Technology is also involved in this research work.
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