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Pre-electrical Lamps

Early Man
The first lamps were invented around 70,000 BC. These lamps, made from naturally occurring materials, such as rocks, shells, horns and stones, were filled with grease and had a fiber wick. Lamps typically used animal or vegetable fats as fuel. Early man also realized that a crude reflector would help direct and intensify the light.

The fuel used in ancient lamps, depended largely on availability. Olive oil was probably the principal fuel employed in the Mediterranean countries, and was exported to areas where the olive did not grow. Other oils which were probable used in lamps include sesame oil (mainly in the East), nut oil, fish oil, castor oil and other plant oils.

Lamp fuels were editable, so lamps were more likely to be used by the wealthy than the poor. In times of hunger, fats would be consumed by the poor, and they would have less fuel available for their lamps.

In the ancient civilizations of Babylonian and Egypt (3000 BC) for example, light was a luxury. The Arabian Nights were far from the brilliance of today. The palaces of the wealthy were lighted only by flickering flames of simple oil lamps. These were usually in the form of small open bowls with a lip or spout to hold the wick. Animal fats, fish oils or vegetable oils (palm and olive) furnished the fuels.

Oil Pottery Lamps
After the natural oil lamp, then the crude worked lamp, pottery lamps followed. Early Greek pottery were hand-modeled. Pottery lamps were a cheap and practical means of illumination, easy to produce, easy to use, but rather messy to handle. The oil would often ooze from the wick hole and run down the outside of the lamp.
During the 6th, 5th and 4th centuries BC, Athens was a major manufacturer and exporter of high quality poetry lamps. Lamps similar in basic design may still be used today, in some parts of the world.

Candle
The invention of the candle dates back to about 400 A.D., perhaps somewhat earlier. Relatively few candles were used in the home until about the 14th century, however they were an important symbol of the Christian religion. The best candles were made of beeswax and were used chiefly in church rituals because the bee was regarded as a symbol of purity. But because beeswax was expensive, crude tallow candles had to be used by the common people. Tallow was smelly and smoky. The candles dripped badly and generally gave a feeble light.

Theory of light by Sir Isaac Newton
Sir Isaac Newton was an English scientist and mathematician who greatly contributed to many fields of science including; motion, gravity and optics. He was first to formulate the corpuscular theory of light. Newton said that luminous bodies radiate energy in particles or corpuscles, and that these particles are ejected in straight lines. The particles then act on the retina of the eye in a manner to stimulate the optic nerve and produce the sensation of vision in the brain.
In 1666 Newton at the age of 23, performed his famous prism experiment. He noticed and recorded that sunlight is white light that contains all the colors of the spectrum. In 1704 he published the first edition of his famous book 'Opticks'. Newton correctly identified the principals of refraction associated with his experiment in that light is bent as it travels from one medium to another at a slight angle, dependent on its wavelength. He didn't know that he was repeating what Leonardo da Vinci had noted down, in mirror writing, approximately 200 years earlier.

Newton, like others before him also tried to discover a link between light and color and between light and sound. He considered that these divisions corresponded to the diatonic scale. Early scientists always considered the primary colors to be relatively large areas of the spectrum: red, orange, yellow, green, blue and violet. However in 1666, named a 7th color located between blue and violet, as indigo. He wrote: " Considering the lastingness of emotions in the bottom of the eye by light, are they not of a vibratory nature? Do not the most refrangible rays excite the shortest vibrations - the least refrangible the largest? May not the harmony and discord of colors arise from the proportions of the vibrations propagated through the fibers of the optic nerve into the brain, as the harmony and discord of sounds arise from the proportions of the vibrations of the air?"

The answer to Newton's question today, would be no! His color scale was as follows:
• Red - C
• Orange - D
• Green - F
• Blue - G
• Violet - B
• Indigo - A

Discovery of the Ultraviolet Light (UV)
The 'dark portion' of the solar spectrum (adjacent to violet light) was discovered in 1801 by the German physicist Johann Wilhelm Ritter and was named 'ultraviolet' radiation.

Today we classify UV radiation as follows:

• UV-A (320-400 nanometers) - which is adjacent to visible light, is often referred to as near-UV or black light. This band is the least energetic UV radiation.
• UV-B (290-320 nanometers) - lies in the middle spectrum. It is commonly known as erythemal UV and is the band that converts ergosterol in the skin to vitamin D.
• UV-C (160-290 nanometers) - is the shortest UV wavelengths, and because of its effectiveness of killing one cell organisms, is called germicidal UV. The shorter wavelengths produce ozone in air (oxygen).

Oil Lamps
In the 18th century, the central burner was invented. The fuel source was now tightly enclosed in metal, and a adjustable metal tube was used to control the intensity of the fuel burning and intensity of the light. Around the same time, small glass chimneys were added to lamps to both protect the flame and control the flow of air to the flame. Early lighting fuels consisted of olive oil, beeswax, fish oil, whale oil, sesame oil, nut oil, and similar substances.

The kerosene lamp – as a widely important invention – was introduced in Germany in 1853. Kerosene was distilled from petroleum obtained from oil shale, found in mines. By 1856 Kerosene was used to light homes in New York (gas came to that city in 1864.)

Gas Lights
In 1792, the first commercial use of gas lighting began when William Murdoch used coal gas for lighting his house in Redruth, Cornwall. German inventor Friedrich Winzer (Winsor) was the first person to patent coal gas lighting in 1804 and a "Thermolampe" using gas distilled from wood was patented in 1799.

Early in the 19th century, most cities in the United States and Europe had streets that were gaslight. Gas lighting for streets gave way to low pressure sodium and high pressure mercury lighting in the 1930s and the development of the electric lighting at the turn of the 19th century replaced gas lighting in homes.

Gas Lighting (ENGLAND)
The first general use of gas street lighting took place in London in 1814. By 1823 nearly 40,000 lamps had been installed in 215 miles of London streets.

It was the introduction of gas lighting to the theatre that began the first real advance in theatre lighting. Gas was manageable and controllable. Centralized remote control systems were developed, usually in wings, backstage. The 'gas plate' contained control valves between the main gas supply and each gas lighting 'circuit', and allowed the footlights, wing lights, etc. to be dimmed, brightened or extinguished at will.

Gas Lighting (AMERICA)
Gas lighting was introduced to the American theatre in 1816 at the Chestnut Street Theater in Philadelphia. In 1926 the Bowery Theater was the first in New York, to be lighted by gas. The theatre burned nine times before it was demolished in 1930. There was no gas lighting in Chicago theatres, prior to 1850, when the first municipal gas works were constructed.

As municipal gas companies did not exist throughout the country, each theatre had to manufacture their own supply of gas. Although gas had many advantages over oil lamps and candles, it is said that several hundred theatres burned down in Europe and America from the use of gas lighting.

Electric Lamps

Electric Arc Lamps
In 1809, Sir Humphrey Davy first demonstrated the electric carbon arc at the Royal Institution in London. The electric arc was also used for lighting at the Paris Opera. At that time and until about 1860, the only source of electrical power came from batteries. After the electric generator developed sufficiently, there was a surge of activity from 1878 onwards.

Electric arc lamps were introduced outside the Paris Opera in 1877. These were candles in which two parallel sticks of carbon where separated by an insulator which was melted slowly away by the arch thus self-feeding the two carbons.

By 1884 there were 90,000 electric arc lamps burning by night in the USA, where development was on a greater scale than elsewhere.
The principal of the electric arc is still used today by many older followspots and film projectors, used in entertainment facilities around the world. Modern followspots and projectors now tend to rely on a High Intensity Discharge, (Xenon, CSI, HTI, etc.) lamps, instead.

How Arc Lamps Work
A carbon arc lamp works by hooking two carbon rods to a source of electricity. With the other ends of the rods spaced at the right distance, electrical current will flow through an "arc" of vaporizing carbon creating an intense white light.

All arc lamps use current running through different kinds of gas plasma. A.E. Becquerel of France theorized about the fluorescent lamp in 1857. Low pressure arc lights use a big tube of low pressure gas plasma and include: fluorescent lights and neon signs.

First Electric Incandescent Lamps
Although Edison did not invent the electric filament lamp, he did however turn theory into practicable form and was one of the first to successfully market incandescent lighting. The first Canadian patent covering an incandescent lamp was submitted by Henry Woodward and Matthew Evans, dated July 24, 1874 - approximately five years before the development of the Edison lamp. It was probably however, the German chemist Herman Sprengel who pioneered the vacuum light bulb in 1865.

Reference: for further information consult the MIT studies of invention publication, authorized by Arthur A. Bright, entitled "The Electric Lamp Industry".

Edison Lamp vs. Swan Lamp
Edison's first successful lamp used carbonized cotton thread as a filament, installed in a glass bulb, with all air evacuated. On the afternoon of October 21, 1879, Edison's prototype had lasted 45 hours. The next day Edison began to experiment using cardboard as a filament. The cardboard filament was even more successful, and in a couple of months, production of his lamps had increased. On New Year's Eve, December 31, 1879, Edison gave his first public demonstration of his new invention, at Menlo Park, New Jersey. Special trains were run on the Pennsylvania Railroad to accommodate the masses of visitors. About 100 cardboard filament lamps were used in this demonstration, lighting the streets, the laboratory, and the station at Menlo Park. Each lamp was rated at 16 candlepower and consumed about 100 watts. (Average life was about 100 Hrs.)

In 1880 Edison experimented with other materials for filaments, including wood, grasses, hair and bamboo. Of the over 6000 specimens tested by his laboratory, bamboo, became commonly used for filaments.

In 1880, on January 17, Patent number 223,898 was issued to Edison for the T.A. Edison Electric Lamp.

In 1881, two years after the first incandescent lamp left Edison's workshop, the steamship 'Columbia' was fitted with a thousand of them. Within another two years, there were over 300 electric power stations in existence, feeding over 70,000 incandescent lamps, each with an average life of 100 hours.

Along with, (and others) Joseph Swan, is also credited with inventing the incandescent lamp. Swan demonstrated a carbon filament lamp to about 700 people in Newcastle-upon-Tyne on February 5, 1879.

Swan's development of the incandescent lamp was reported in the Oct. 29th, 1880 issue of "Engineering", which quotes him as follows: (SWAN) "Electric lighting by incandescence is just as simple as arc lighting is difficult, all that is required is a material which is not a very good conductor of electricity, highly infusible and which can be formed into a wire or lamina, and is neither combustible in air, or if combustible, does not undergo changes in a vacuum".

The first premises to be lighted by the new Swan lamp were those of Sir William Armstrong at Cragside near Newcastle in December 1880.

How Incandescent Lamps Work
Incandescent lightbulbs work in this way: electricity flows through the filament that is inside the bulb; the filament has resistance to the electricity; the resistance makes the filament heat to a high temperature; the heated filament then radiates light. All incandescent lamps work by using a physical filament.

Thomas A. Edison's lamp became the first commercially successful incandescent lamp (circa 1879). Edison received U.S. Patent 223,898 for his incandescent lamp in 1880. Incandescent lamps are still in regularly use in our homes, today.

Lightbulbs
Contrary to popular belief, Thomas Alva Edison did not "invent" the first lightbulb, but rather he improved upon a 50-year-old idea. For example: two inventors that patented an incandescent lightbulb before Thomas Edison did were Henry Woodward and Matthew Evan. Using lower current, a small carbonized filament, and an improved vacuum inside the globe, Edison successfully demonstrated the light bulb in 1879 and, as they say, the rest is history."

Footcandle (FC)
It was in the early days of electric lighting that users began to ask how much light they needed. The measurement unit of the footcandle was developed as a measure of 'illumination'.

The definition of footcandle is: “The unit of illuminance when the foot is taken as the unit of length. It is the illumination on a surface, one square foot in area on which there is a uniformity distributed flux of one lumen, or the illumination produced on a surface all points of which are at a distance of one foot from a directionally uniform point source of one.”

Lux (Lux)
The International (metric) unit of illumination is the 'lux'. It is the illumination produced on a surface one square meter in area at a distance of one meter from a uniform point source.

Lux / Footcandle conversions

FC   = LUX x .0929 -    Example 1:   500 Lux x .0929 =  46.5 FC
Lux  = FC x 10.76   -    Example 2:    50 FC  x 10.76 =  538 Lux

Generally you may multiple FC by 10 to obtain LUX - or, divide LUX by 10 to obtain FC.
The recommended illuminance levels for various activities and tasks are published by the Illuminating Engineering Society. Today we know that it is not just the 'amount' of light that affects visibility. Other factors such as contrast and glare are equally important.

The illumination from the sun on the earth's surface can exceed 100,000 LUX, (or 10,000 FC) during a summer day. At night the reflected light from the moon might be as high as 0.2 LUX, (or .002 FC).

Candlepower
In 1860, one of the basic lighting measurements, the candlepower, was established using a Spermaceti candle, of a specific weight and burning at a particular rate, as the basis.

Gas Discharge or Vapor Lamps
American, Peter Cooper Hewitt patented the mercury vapor lamp in 1901. This was an arc lamp that used mercury vapor enclosed in glass bulb. Mercury vapor lamps were the forerunners to fluorescent lamps. High pressure arc lights use a small bulb of high pressure gas and include: mercury vapor lamps, high pressure sodium arc lamps, and metal halide arc lamps. .

Tungsten Filaments Replace Carbon Filaments
American, Irving Langmuir invented an electric gas-filled tungsten lamp in 1915. This was a incandescent lamp that used tungsten rather than carbon or other metals as a filament inside the lightbulb and became the standard. Earlier lamps with carbon filaments were both inefficient and fragile and were soon replaced by tungsten filament lamps after their invention.

Fluorescent Lamps
Friedrich Meyer, Hans Spanner, and Edmund Germer patented a fluorescent lamp in 1927. One difference between mercury vapor and fluorescent lamps is that fluorescent bulbs are coated on the inside to increase efficiency. At first beryllium was used as a coating however, beryllium was too toxic and was replaced with safer florescent chemicals.

The fluorescent lamp was first introduced to the public at the New York World's Fair in the late thirties (1937). The lamps were introduced commercially in about 1938. The fluorescent lamp is a low pressure gas discharge source, in which the light is produced predominantly by fluorescent powders activated by ultraviolet energy generated by a mercury arc.

The lamp is usually in the form of a long tubular bulb with an electrode sealed at each end. The modern fluorescent lamp has an efficacy of approximately 65-80 lumens per watt. Today fluorescent lamps are also available in circular and 'folded' shapes. Lamps with various different color temperatures and color rendering properties are commonly available. The most common fluorescent lamp is the CW or cool white version, although new 'warmer' versions are now gaining popularity, worldwide. All fluorescent lamps require ballast, for operation.

Developed in the late 1980's the compact fluorescent lamp revolutionized the lighting industry. This lamp (also referred to as the PL lamp), is simply a folded fluorescent tube, sometimes no larger than a standard 'light bulb'. The ballast is usually mounted in the base pf the lamp. This new lamp allows most household incandescent lamps to be replaced with these new energy saving fluorescent lamps. In addition to retrofit applications, new 'pot light' fixtures have been developed specifically for the PL lamps, for residential, commercial and industrial lighting applications.

Halogen Lights
U.S. Patent 2,883,571 was granted to Elmer Friedrich and Emmett Wiley for a tungsten halogen lamp - an improved type of incandescent lamp - in 1959. A better halogen light lamp was invented in 1960 by General Electric engineer Fredrick Moby. Moby was granted U.S. Patent 3,243,634 for his tungsten halogen A-lamp that could fit into a standard lightbulb socket. During the early 1970s, General Electric research engineers invented improved ways to manufacture tungsten halogen lamps.
In 1962, General Electric patented an arc lamp called a "Multi Vapor Metal Halide" lamp.

High Pressure Sodium Lamp
H.P.S. (HPS) - The high pressure sodium lamp has steadily developed and gained in popularity, since its introduction 1966. It provides a more economical source of illumination than mercury, fluorescent, or incandescent and has a more natural color than low pressure sodium.

Light Emitting Diode
The light emitting diode (LED) is p-n junction semiconductor lamp which emits radiation then biased in a forward direction. The emitted radiation may be either invisible (infrared) or in the visible spectrum. Visible solid state lamps are used for long life indicator service. Infrared diodes have outputs carefully matched to silicon photoreceivers. They are used in conjunction with the receivers, for counting, sensing, and positioning applications. LED's generally operate in the range of 1 to 3 volts at currents of 10 to 100, milliamperes continuous.

LED's are commonly used in indicator lighting applications. Due to their very long life and low operating current, they are ideal replacements for incandescent indicator lights. Early LED's came in red only. Next green and amber were introduced. By the mid 1990's blue and white LED's had been developed.