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.
185. White walls and more than one window:
Bright sunlight outside, 2 seconds; hazy sun, 5 seconds; cloudy bright, 10 seconds; cloudy dull, 20 seconds.
186. White walls and only one window:
Bright sun outside, 3 seconds; hazy sun, 8 seconds; cloudy bright, 15 seconds; cloudy dull, 30 seconds.
187. Medium colored walls and hangings, and more than one window:
Bright sun outside, 4 seconds; hazy sun, 10 seconds; cloudy bright, 20 seconds; cloudy dull, 40 seconds.
188. Medium colored walls and hangings and only one window:
Bright sun outside, 6 seconds; hazy sun, 15 seconds; cloudy bright, 30 seconds; cloudy dull, 60 seconds.
189. Dark colored walls and hangings and more than one window:
Bright sun outside, 10 seconds; hazy sun, 20 seconds; cloudy bright, 40 seconds; cloudy dull, 1 minute and 20 seconds.
190. Dark colored walls and hangings and only one window:
Bright sun outside, 20 seconds; hazy sun, 40 seconds; cloudy bright, 1 minute, 20 seconds; cloudy dull, 2 minutes, 40 seconds.
191. This table is intended for rooms with windows receiving the direct light from the sky, and for the hours from three hours after sunrise until three hours before sunset. If earlier or later the time required will be longer.
Exterior Exposures. When the size of the diaphragm of the lens is reduced to, say, about half, the light admitted through a lens is so much reduced that even out of doors a time exposure may be made just the same as for interior pictures; but as the light out doors is much stronger the time exposure must be correspondingly shorter. With sunshine the shutter can hardly be opened and closed quickly enough to avoid over-exposure. With light clouds, from one-half to one second will be enough. With heavy clouds, from two to five seconds exposure will be required. This is calculated for the time from three hours after sunrise until three hours before sunset, and for objects in the open light. For other times, or for objects in shadow, under porches or trees, no accurate directions can be given; in fact, experience only can teach you to give the proper exposure. Remember, that time exposures cannot be made while the camera is held in the hand. Always place it on some firm support - tripod preferred.
193. In order to become familiar with the proper timing under all strengths of light, take your camera and load it with a double-two film. Select a sunshiny day, and a street that has bright sunlight on one side and shade on the other. Step into the middle of the street and photograph the view which is in bright sunlight, setting the speed of the shutter at 1/25, or if your camera is not equipped with a shutter of different speeds, use the instantaneous attachment, adjusting the view on the finder so that the far end of the street will show in the picture. Then make the exposure, after which turn off the exposed film until number 2 appears. Make another exposure identical with the first. Then wind off this exposure until number 3 appears, which means quite a number of turns (if a double-two film has been used), as a long strip of black paper separates number 2 from number 3.
194. If you have not used a tripod or some solid support for the kodak in making the first two exposures, do so for the remaining two exposures, as one of these is to be a time exposure, and it is impossible to hold the camera steady even for one second. Now, without changing your original location, point the camera toward the shady side of the street and make another exposure, giving the same "snap-shot" time as you did on 1 and 2, after which wind up the exposed film until number 4 appears. Then set your shutter so as to make an exposure of one-half second, or if your camera is not equipped with a shutter that can be set at the different speeds, set it for time exposure, indicated on the dial by T.
195. When the shutter is set for a time exposure, you will have to press the bulb or button, or push the lever twice (depending on the kind of shutter you have). The first pressure opens the shutter and exposes the film; the second pressure closes the shutter. If you open and close the shutter as quickly as possible (without jarring the camera), you will secure an exposure of about one-half second. In making time exposures, do not move the camera in the least, for in so doing you blur the image on the film. After making the fourth exposure, remove the film as previously directed. Three of these exposures are properly timed; numbers 1 and 2 in strong sunlight and number 4 of the shady side of the street, to which you gave one-half second exposure. This one-half second exposure, made of the shady side of the street, will not affect the sensitive film any more than the snap-shot on the sunny side of the street did. Number 3, which is a snap-shot of the shady side of the street, will be under-timed and yield a very poor picture. Our object in having this under-timed exposure is to show that snap-shot exposures cannot be made of any subject in the shade.
196. It is not necessary to use a street scene for these experiments. Any view will do which shows strong sunlight and shadow. You can apply the same method to a house first making an exposure from a point with the sun shining on the house, then making another exposure on the side in shadow. Both exposures will illustrate the same effect. With a 6-exposure film, expose numbers 5 and 6 on some public building or residence, making instantaneous exposures of both under different circumstances.