This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Introduction. It often will be found inconvenient and practically impossible to secure a portrait lighting in the home on account of the location or size of the windows. It may be desirable to make portrait lightings at night and, of course, the daylight could not then be employed. An excellent substitute for daylight for the At-home portrait worker, is to be found in the flash-light, and the modern compounds on the market at the present time will be found available for this purpose, as they are practically instantaneous and there is very little likelihood of any movement of the subject.
487. As a rule, the first attempts to make photographs by flashlight result, in a vast majority of cases at least, either in partial or complete failures, causing many to become discouraged and to give up making further attempts at this feature of photography. As a rule the difficulty is always due to lack of knowledge of the peculiarities of flashlight work. If ordinary precautions be taken and the instruction contained in these lessons carefully followed, results equal to daylight will be secured. If much portrait work is to be done by flashlight, it would be very advisable to employ a simple and practical flash-lamp - one that is perfectly reliable and safe, easily set up and operated, and occupies little space. The flash-powder should be one that is safe, instantaneous, yet not highly explosive, producing the greatest amount of actinic light, of uniform mixture, leaving no undesirable odor and giving off the least amount of smoke.
488. Flashlight for portraiture will produce exactly as good negatives as daylight, for while the light is concentrated yet it is under perfect control for shading and for softened effects. One advantage the flashlight has over daylight, especially in At-home Portraiture, lies in the exposure, which is instantaneous, the amount of exposure being measured only by the amount of powder used. These conditions being always the same, you can invariably give a uniform exposure; accuracy in timing the negative is therefore a very easy matter.
Illustration No. 35 Nichols' Junior Flash-Lamp. See Paragraph No. 489.
489. Of course it is not necessary to go to the expense of purchasing a flash-lamp. You can easily construct a simple piece of apparatus which will answer the purpose, but it is, naturally, not so convenient. One of the most successful and practical lamps and one which has been on the market long enough to have been thoroughly tested, is the Nichols' Portrait Flash-Lamp. This lamp, however, is intended more for professional work. (See Illustration No. 34.) A smaller size, known as the Nichols' Junior Flash-Lamp, is intended particularly for home portraiture and is a very convenient lamp to operate and is also perfectly safe. (See Illustration No. 35.)
490. The powder in this lamp is ignited by means of a small quantity of alcohol which is forced through a flame onto the powder. The alcohol, being ignited in passing through the flame, produces a large spread of flame which is forced down on to the powder by the pressure of the air following. There are two cones fastened to the flash-pan. One-third of the whole charge of powder is to be used in front of and between these two cones, not spreading it out, but placing it in the shape of a V. The remaining two-thirds of the charge should be placed in the two cones so that the holes in the apexes are filled and the powder unites with that placed between them. There will then be three separate lots of powder all connected at the center. 491. Explanation of Front View - Illustration No. 36. - H H H - Safety back completely separating the alcohol flame from the flash-powder; K - Cap over the end of the blast-tube, employed to spread the flame of burning alcohol, throwing it in such a manner that flash-pan, J J J, is covered with a mass of flame with the result that the powder is sure to ignite instantly; II - Two cones into each of which one-third of the whole charge of powder is placed, the remaining one-third placed in front of cones and the piles uniting at the ends, L L. The powder in the cones, when ignited, forces the flame out to either side, giving a very broad flash flame; M is a hole into which the folding screen is fastened.
Illustration No. 36 Sectional Front View of Nichols' Flash-lamp. See Paragraph No. 491.
492. Explanation of Rear View - Illustration No. 37. - H H H - Safety back; E - Alcohol lamp burner; B - Brass tube, to which the rubber tube running to bulb is attached; A - Spring holding alcohol reservoir, C, in place; G - Brass tube through which a small quantity of alcohol, which is automatically trapped, is forced by a pressure of the bulb through blast tube F onto the flash-pan. This small quantity of alcohol on passing the flame from the burner E is ignited, forming a great mass of flame which insures instant and noiseless ignition of the powder placed on the flash-pan.
Illustration No. 37 Sectional Rear View of Nichols' Flash-lamp. See Paragraph No. 492.
493. A regular standard may be purchased with the lamp, which is convenient and light, handy to carry and has an elevation of over ten feet, ample for all practical purposes.