T ABLE I Open-air Subjects Second Clouds . . . . . . . . Boats at sea, distant . . . . .
Second Boats at sea, near . . . . . .
Sea beach, waves, etc. . . . . Landscapes : Open common ; or open subject with no strong objects Average landscape : cottages or trees in pro minent ,..., position . . . . . 'Trees in full leaf near camera . . 1 t Trees in full leaf very near ; part of trees only included in picture . . . . . 1 Woods : photographs taken under strong foliage . . . . . . x to 5 Buildings : Large buildings, general views . . . Cottages, small buildings . . . 11Street scenes . . . . .
Narrow streets . . . . . . 1 1Details of buildings . . . . 1 to 1 Portraits : Group or full-length figure . . . .
Head and bust . . . . . . xStill-life, flowers, etc., full-size . 2 to 8 Larger objects, according to distance . 1 to I Interior Subjects Cathedrals and churches : Nu Nave or general view 45 sec. to 2 min.
Aisles, white glass windows. . to 3 rain.4), Aisles, stained-glass windows . yhv to 7 min..3: Choir " 4 to x5 min.
crypt . . . . . so to 6o min.
Ordinary rooms in modern houses . to 3 min.
Workshops . . . . 3o sec. to min. Rooms or workshops with skylights x o to 20 sec. Portraits in well-lighted room . xo to 25 sec. Still-life, flowers, etc., full-size, near window . . . . so sec. to ikin.
All the above times are sufficient to secure a fully-exposed plate. The boats at sea described as " near ' are those that nearly fill the plate ; those called " distant " are small in relation to the size of the picture. In the landscape subjects de scribed as " open common," etc. are included all those that have no object wit:h any depth of shadow within one hundred feet. Small bushes, lower than the camera, can be disregarded, as the camera, in looking downward, photographs them from above, the direction in which the light reaches them. In all landscape work,; heavy foliage will require a longer exposure than the longer for one that is comparatively dark, with small windows or those seriously obstructed - by outside objects. Dark woodwork in churches,
especially if near the camera, will always necessi tate a longer exposure than if the subject con ,' sists of light-coloured stone. In domestic interiors, the same principle regarding windows applies equally ; and the colour of the walls and - the furniture will also affect the exposure. In the case of an unfurnished room, the exposure Army be reduced to half that given in the tables. "The exposure for flowers and still-life subjects will be influenced by the colour, the degree of ;, contrast, and also by the manner in which the light from the window falls on it.
These exposures, being correct for the best possible light in June, must be multiplied by the figures obtained from the graph (called "Table IL"), in which the thicker horizontal lines represent the hours and the fine horizontal lines quarter-hours. The fine vertical lines corre spond to intervals of five days for each division, the dates being given under every alternate line. It is practicable to read off the correct figure for any day, and for any time in the day. thick curved line has its multiplying figure 9'4 shown on it. This figure is indicated for any date and time by the point at which these curved lines cross the horizontal and vertical : exposures exposures are for a plate having a speed of 200 H. and D. Most modern rapid plates are about this speed, but the makers give the rapid ities in almost all cases. The exposure for other plates will be directly proportionate to their any other subjects at the same distance, on account of its colour and strong deep shadows.
In all the interior subjects, a range of expo sure is given. The shorter is for a well-lighted subject with large and unobstructed windows, rapidity ; thus a plate ioo H. and D. will require twice the exposure of one having a speed of 2oo H. and D.
These exposures are for f/16, a medium aper ture. The relative exposures for other apertures are given in Table IV.