thus suffer a derangement or loss of some portion of its actinism, which is probably the reason that in practice the quality of light is found better which has passed through a circular form of glazed surface, which always presents the same conditions to the incidence of the luminous principle, whatever maybe the angle at which it impinges upon it. - Lake Price.

Fig .43.

Fig .43.

207. Screens and reflectors are made use of, of many forms, to control and drive the light as and where wanted. Top and side curtains also come largely into service for the same purpose. At one time it was very fashionable to blue-frost the inside surface of the glass, in order to soften and modify the light. Some used ground-glass, others paint, to soften the effect of the light, but always at the expense of rapidity. Screens and curtains are the best, because the most adjustable, and give one the power and control over the light to change it as the days change, which any permanent coating upon the glass could not allow.

207. How can we obtain perfect control over the effect of light on our model, without materially diminishing the photographic power of that light? That is the problem to be solved, and we may as well say at once we have not wholly solved it, but we believe we have found a valuable clue to its solution, and it has the advantage of having been practically tested in our own studio, instead of being a mere theoretical suggestion. We have a large amount of skylight, with very little side-light; by which we mean, that our principal light is derived from the roof, with only two small windows at the side. This roof-light is a ridge roof, thus a, facing north and south, and contains two lights twelve by fifteen feet each. Thus we have a large source of light to begin with, and we have tried to manage it by various systems of blinds." None, however, satisfied us, for when we had shut out the light by blinds until we obtained the desired effect, the exposure was considerably lengthened, and this we hold to be, on many grounds, objectionable. Here was the difficulty, and every photographer who aspires to the production of a picture must have felt it. We have largely overcome it by abolishing the blinds and substituting a flat roof at the base of the angle formed by the roof-light, thus, This flat roof consists of a light wooden framework, upon which are laid screens, formed by covering very light iron frames of about one square yard with oiled paper. Any one of these screens can be raised by pulling a string. And what is the effect? Above, there is all the light that the roof can admit, and this penetrates the roof formed by the paper screens we have mentioned, and gives a soft diffused light all over this part of the room. But this cannot produce the harmony you speak of, and must enormously lengthen the exposure. Stop a minute; let us raise one of the screens to an angle, and observe the effect. A strong light enters through the aperture thus formed, all the stronger by the reflection from the screen; and do you not see it falls exactly where we desire it? Any effect may be thus obtained by raising and lowering these doors in our false roof; and as the light has but a short way to travel, you obtain a far more powerful effect than by admitting the same amount of light at the glass roof above. - J. M. Burgess.

Another system which is very practical and easily managed where there is plenty of room, is, first, one set of white curtains for the light and an inside room, mounted on casters, and covered on both sides and top with sectional curtains of white muslin; the form of the room to be as our glass - rooms are usually constructed. It must be high enough for a half or

208. Of the curtains,it is best to have two systems, one working from the bottom towards the top, and the other from the top towards the bottom of both top- and side They should be of blue or gray stuff, thick enough to exclude light entirely, and worked upon spring rollers. The should lap. The screens may be of thin white muslin. Paper will answer, hut it soon gets out of repair and is troublesome.They should be stretched on light frames running on wires and moved to and fro by means of cords or a rod. With enough of these, almost any possible effect can be managed by the skilful operator.

809. In constructing a glass studio, certain other items should be considered, as follows: a means of leaning the outer surface of the glass of the accumulations of dust and dirt; a protection from hail; outward sun - shades; proper ventilation; leakage; a solid floor to prevent movement of the subject during exposure; lastly, a proper color for the walls, which should be of some cold, neutral tint. As to this last, a word more. Remember that if the walls are too light in color, the reflections which they cause will continually annoy you. A dark gray is easily kept clean, and does not disturb your management of the light used in making the portrait.

Fig. 44

Lesson J The Glass Studio 64

208. There is no better color for shades than white, for you are enabled to judge correctly the strength of every light, and the depth of every shadow. For semi-opaque shades, a drab color will never confuse by false impression of the density of your shadows. - L. G. Bigelow.

200. The writer has applied with success, a simple means whereby cleanliness of the glazed roof, at the least trouble and outlay, is promoted, whilst at the same time, the intense heat to which the glass studio is exposed during the summer months is greatly mitigated by evaporation from its surface. Carry along the ridge of the top a leaden or zinc pipe perforated with holes; it can either communicate direct with a cistern - above its level - and be made to act by turning a stop - cock, or can be connected with a small forcing-pump, which is inexpensive. By allowing the water to percolate from it, at intervals during the day, the heated glazed surface is greatly cooled, whilst at the same time accumulated dust, soot, etc., are removed. - Lake Price.