In taking up this subject it is our desire to be understood as giving only our own experience in working the different lights which we shall mention. We do not intend writing of anything that we heard, but that which we know to be so, for we were there. At the same time we cannot fail to realize that this is a question over which nearly all operators will agree to disagree. Each will have his own particular pet of a light, and he will laud it to the skies, to the detriment, if possible, of all others. One will say single slant is "the thing." Another will say "nit;" there is nothing like the old-fashioned double slant. So far as our own personal opinion goes, we can see good and bad features in both. The thing for the operator to do is to get all the good features out of either he can, and do away with as many of the bad features as possible. Again, we should always consider the size of our operating room in putting in a light. This is a most important matter and should receive our closest attention, for we may later on regret that which we have done. We will make use of a few sketches to illustrate our remarks, and will endeavor to describe each sketch, so that our meaning will be perfectly clear to our readers.
In Figure 1 we have a double slant light with a slant of about 45 degrees, and we will say the top light is ten feet wide and ten feet high, the side light being ten feet from the floor, the light coming to within three feet of the floor. We think we will be safe in saying there are more lights of this description in use than any other style.
Suppose we have an operating room 15x30 feet in size; this light would be just what we would put in. The main reason is that we can work nearer to this style light than we can to a single slant, and our room is not broad enough to allow us to get far enough away from a single slant. In our opinion the principal reason why some have had trouble in working a single slant light lies in the fact that they try to work too near the light. We must bear in mind that in working a single slant light we must do so in such a way that we get a side and top light too. For example, suppose we place our sitter within about six or seven feet of a single slant, light, we only get a strong side light, causing contrast; our top light all goes over our sitter's head. If we will move our sitter, say eight to ten feet from the light, you will at once see the difference, for we then get the benefit of the lower half of our light, or that which makes side light and also the upper half, or that which makes top light. For this reason, we say, we would put in just such a light as Figure 1 represents if we had an operating room of narrow dimensions. Our reason for preferring this light for close quarters is the skylight comes into the room so far that it allows the light to strike more evenly on the sitter when they are posed nearer the light.
In Figure 2 we have a single slant light of 45 degrees and ten feet wide and twelve feet high. If I had a room twenty-five or thirty feet wide, I should put in this light, for in a room of this size we can get far enough away to secure almost any effect we might desire. This light will also be much more simple to manipulate, from the fact that you do not need so many sets of curtains. You will not be troubled with so many reflections, hence will require less time and expense in curtaining it. Every time we add an extra slant to a light we add that many more reflections, which we must control with curtains. For a room from twenty-five to thirty feet wide, this light will be found far more satisfactory and easily worked than one of a greater angle would be. One of greater angle would not be so good for groups, for the reason that your light is narrow and your room is not wide enough to permit of your posing your group far enough away from your light. In curtaining a light represented by Figure 1, I should want one set of opaque curtains running on rollers from top of skylight down to side light, and another set running on rollers from foot of side light up to skylight. I should want in addition to these a set of diffusing curtains on both my side and top light; more especially on my side light, for it is frequently the case that we get a very strong reflected light, which is most noticeable in Rembrandt effects and usually shows on the side of the forehead next to the light. This we must do away with by the use of diffusing curtains. With a light represented by Figure 2 we do not have this trouble; therefore, if we have a ground glass light of this description, all the curtains we need is a set of opaque, running from the top and another from the bottom, and no diffusing curtains.
Now, having tried to give an idea of what style light we would prefer with certain operating rooms, we will give you a short description of our ideal light and ideal operating room. This light is represented in Figure 3, which is a single slant ground glass of 60 degrees, and is eighteen feet wide and begins four feet from the floor, and extends upward eighteen feet. It is curtained with two sets of opaque curtains only - one set running from top of skylight to the bottom, the other set from bottom of light to the top; thus I can divide my light at any point. My operating room is 40x60 feet, and my light is put in the center of the room. By this means I am enabled to work from either end. With this light and this room we can get any effect desired. We have room enough to get away from our light, and can move our sitter about under our light until we get just what we are after. At the same time our light is broad enough to meet any demands that may be made upon it. It is equally as good for groups as it is for head studies, as we can place them away from the light and use the opaque curtains to tone down the lights in almost any part of the group we may wish. I am well aware of the fact that some operators will question my assertion that by posing your sitter close to the single slant light all the top light goes over the head and has no effect on your lighting. To those who question it I say: If you have a single slant light, make an interior view of your operating room showing your light, and see if the strongest point of light falling from your skylight don't fall at least twelve or fifteen feet away from your light.
In putting in a light we should also bear in mind that the surroundings will also affect the action of any light. If we have a double slant and there is a building within a few feet of our side light, it will cause our light to give us hollow eyes and deep shadows under the nose and chin, caused by our not getting enough side light to tone down the action of our top light. If there are trees around our light we will notice the same effect, especially in the summer time when the trees are in leaf. At the same time the green in the trees will make our light work much slower. This will also be caused by using a cheap grade of glass for your light, as all cheap glass is of more or less green cast. If you put in a light of hammered glass, you should use only the very finest quality, as the thickness of the glass will frequently cause it to have a decidedly green tinge.
We have been asked to give our method for using a south light; as it may be of interest to others we will give it here. First, have your light of heavy ground glass; then have two sets of opaque curtains, running from top and bottom of the light. Also have white diffusing curtains running on wires across both your side and top light. Now attach a wire to the sides of your skylight (see Figure 4) and on this have one width of pink cheese cloth and let it run on rings, so you can move it backward and forward. It should hang loosely between your sitter and the side light. You will find it quite beneficial in shielding your sitter from the sudden changes of light which are caused by clouds passing before the sun.