Ica projectors in 1913

Ica offered a wide range of projection equipment. Almost all of these machines were intended for a double purpose: To project slides against a screen, and to enlarge negatives. The catalog offers more than a dozen pages of projectors that all look very much like this one; the differences are in size, material, quality of construction, and certainly price.

If you are coming from the Ica camera page, it will be no surprise to you that these projectors were sold without a lens. The customer could choose and order the lens separately, having Ica people fit it for him; he could send in an existing lens, to be fitted; or he could use his camera's lens for projection and enlargement, but then he had to order the proper focusing mount for it.

But what may surprise you, is that the projectors did not include the light source! The light box with the nice chimney came empty! The rest of this page is devoted to some of the available light sources for Ica projectors.

Depending on the format (9x12 to 13x18cm for this model), the projectors cost 112 to 186 Reichsmark. There were some optional extras: You could add a carrying case for a few additional Reichsmark, or you could order the lamp housing internally lined with asbestos, for 12 to 18 additional Reichsmark... lung cancer was cheap!

The standard condenser lenses were made of greenish window glass. That was no problem for enlargements or for projecting black&white slides. But if you wanted to project color slides, you could pay an extra 12 to 20 Reichsmark to get condenser lenses made of the famous clear glass made in Jena and used, for example, in Zeiss objectives!

This was the cheapest light source, aimed at home users. Most reputable city homes were connected to the lighting gas grid, and gas lights were widely used for lighting homes, offices, and streets. This lamp worked exactly like modern day gas camping lamps: A Bunsen burner heats an asbestos fabric sock that glows white and emits light. Replacement socks cost 0.60 Reichsmark, and if the glass cylinder burst, it could be replaced for a mere 0.25 Reichsmark.
The lamp was set up inside the projector's lamp housing, connected to the gas grid using a rubber hose (not included), and then you were ready to give a slide show or enlarge your negatives!

For country homes or other places without a lighting gas supply, you could buy this alcohol vapor powered sock lamp. It worked just like the Petromax kerosene lanterns still manufactured today, but the use of alcohol allowed easier starting and less smell. The alcohol tank was pumped to pressure, some alcohol was poured into the preheating cup and set afire. This warmed the evaporator. After a while, you could open the valve and ignite the alcohol vapor in the sock. The heat of the sock kept the evaporator going.

There was a nice micrometric screw to precisely adjust the height of the lamp. The reflector, shown off-location here, was of course installed behind the lamp during use.

This lamp would have been yours for 54 Reichsmark.

This is a chalk light setup. Never heard of them? They were not used much for general lighting, but were a great point source of light for projectors and beam lights!

The drum at left was filled with petroleum ether. The base could be filled with warm water, making the ether evaporate. This was the fuel. The large bottle contained compressed oxygen, which was passed through a regulator and then fed to the burner together with the ether vapor. A very hot, compact flame was produced, which heated a small spot on a little chalk cylinder to white glow. The extremely intense, white light given off by the chalk emanated from an area perhaps 5mm in diameter, making this system as good a point source as our best modern low voltage halogen projection lamps!

Ether could be easily bought in pharmacies, but the oxygen bottles had to be brought to a gas factory for refilling. A footnote states that Ica would gladly tell a customer the location of the nearest oxygen supplier.

The complete setup cost around 100 Reichsmark, depending on some options.

Acetylene gas burns very bright, and is easy to manufacture by joining calcium carbide with water, a fact almost every boy of the time used to employ for making little bombs that were great for purposes such as driving an entire school class, including the teacher, out of the room. The reason is not the bursting of the can in which the reaction takes place, but the horrible smell of rotten eggs that is the usual byproduct of using technical grade, not very pure carbide!

Ica produced a fair range of carbide lamps with varying amounts of flames and sophistication. The "Excelsior" is a minimal device, providing a light power of only 30 Hefner candles, while the "Atom" is more powerful and includes a condensation bag that avoids sending water out along with the acetylene. Both gas generators work by letting water drip slowly onto the carbide.

This intriguing device combined a carbide-based acetylene generator with an oxygen generator based on solid oxygen cartridges, producing an exceedingly hot flame that made a tiny tablet of rare earths glow white. No explanation is given as to what these oxygen cartridges really were; but they cost 1.5 Reichsmark each, lasted for one hour, and were activated by heating them above an acetylene flame in the preheater shown between the acetylene generator and the oxygen regulator. After heating a cartridge, it had to be placed inside the right side steel pressure containers for use.

The entire machinery cost a whopping 300 Reichsmark, so it was intended for serious use only!

Larger cities in Germany had an electric power grid competing with the lighting gas network. So, Ica developed some lamps that could make use of this energy source for projection. This is an arc lamp with carbon electrodes and automatic regulation. As the electrodes slowly burned down, the system automatically moved them closer to each other. It did so by passing the lamp current through the electromagnet. If the current grew to strong, the magnet lifted the electrodes apart, and if it got to weak, gravity pulled the electrodes together. Some setting screws allowed to precisely align the tips.

You have certainly seen arc lamps in action, so you know that they produce extremely bright light. What, are you telling me you have NEVER seen any?  I'm pretty sure that almost everyone has seen some arc welding going on! That's exactly the same process! It IS bright, isn't it?  Now think about using an arc welder as a light source for slide projection! :-)

Ica produced arc lamps for currents ranging from 4 to 100 Ampere! Since the power grid voltage was far from being standardized, most  lamps could be adapted to any of the usual voltages by the insertion of proper ballast resistors. Such resistors had to be ordered for the desired voltage and current, and were custom made by Ica. The smaller ones were the size of a wine bottle, while the largest ones were as large as a washing machine and gave off enough heat to warm an entire house!

Note the total lack of any safety insulation. No safety certifications existed. If you electrocuted yourself by touching the wrong place, that was your own fault.

These were the most modern projection lamps in Ica's lineup! The one at right will look familiar to buffs of ancient lighting technology, but the Nernst Lamp on the left is even a bit more antique! This kind of lamp had a little bar made from magnesium oxide or sometimes some other oxide, which was brought to white glow by current passing through it. So it was a true glow lamp, but operated in air, with no bulb! A ballast resistor was necessary to avoid thermal runaway. The oxide is an insulator at room temperature, so that early Nernst lamps had to be started with a match! "Modern" ones like this were self-starting, thanks to a small heating element. My thanks to Trygve Sørdal and Johannes Assenbaum, who both pointed me to an explanation of this interesting device with just two days interval!

What puzzles me is that the customer had to state if the lamp was desired for DC or AC.DC versions even came with polarity checking paper! Another surprise, this polarity checking paper... 

The power cord was not included. But the glow lamp on the right did include the cord.

The footnote is interesting: When purchasing any of these two lamps, the customer had to pay an imperial tax on electric light! The Emperor William II wanted 1 Reichsmark for each glow bulb sold, 1.80 for a Nernst lamp connected to 110V, and 3.40 Reichsmark for a 220V Nernst lamp!

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