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.
Securing Even Illumination. If the light is all taken from one side of a room, to fully illuminate the far distant portions, the angle of the light must lead toward those portions and away from the camera. The camera should always be placed with the source of light back of it, and leading into the picture. In this way the light traveling forward will carry the illumination ahead of it, while, should you work in the opposite direction, you will be working against the light and, in consequence, be photographing the shadow side of objects instead of the high-lights.
114. Where windows are admitted into the view, have other sources of illumination to light the remainder of the room, also to offset the strong light coming from the window which has been admitted into the scene. Under the latter conditions draw the shade on the window admitted into the view, for a portion of the exposure; then raise the shade for the remaining time, and the window will show in the view without a blur, and you will also have little trouble with halation.
Obtaining A General View Of The Room. When using a long focus rectilinear lens, if the room is small it will be a difficult matter to photograph the greater portion of it; therefore, select only a section of the room - one corner and one side, for instance. Where a wide-angle lens is employed, it is often possible to show both sides and one end of the room. Be careful, in finally adjusting the camera, not to show too much ceiling or floor. Try to produce proper balance, and always be careful that vertical lines, window and door casings are perfectly true.
Arranging The Furniture. Make no attempt to change the arrangement of the furniture according to any set plan. Place each piece in a natural position. If trouble is experienced with white spots, caused by the reflection of light on polished furniture, it is better to turn the offending chair or table a little to one side or the other, to overcome these reflections. Usually, these will give little trouble if there is no sunlight coming through the windows, for then a general diffusion of light is obtained throughout the room. Never have furniture close to the camera. If the room is small, it is better to remove any piece of furniture that may be directly in front of the lens.
Focusing. As the light indoors is so much weaker than outside, naturally the image will not appear very strong upon the ground-glass. You should always focus without a stop. Cover the head and the camera with thick focusing cloth, through which no light can enter; then, with the left hand draw the ends of the cloth under your chin, so no light other than that which comes through the lens will be admitted. Adjust the focus and stop down sufficiently to give good definition.
Judging Proper Exposure. This is one of the most difficult features of interior photography, which practice alone will enable you to learn to judge properly. The appearance of the image on the ground-glass is the only positive guide. If it is bright, you will understand that less exposure is necessary than if it were dull and dim. The amount of dullness determines the length of exposure. If you will observe the different rules for the approximate judging of proper exposure given in this instruction, and will try them out carefully, the experience should materially aid you in judging necessary exposure. Keep a careful memorandum of all exposures of first work, accurately noting time of day, conditions of light, color of objects you are photographing, etc. When developing the plate, if you find the time has been misjudged, it being under-exposed, the next time you make an exposure under like conditions govern yourself accordingly and time longer. There is little danger of over-exposure in interior photography, so have no fear of over-timing. If difficulty is encountered in giving sufficient exposure, try to overtime, when it is quite certain a properly exposed plate will be the result.