242.The time of exposure must next be considered.Too much impatience is indulged in here. Take enough exposure, whenever the subject in hand will permit it. Do not under time, if you can help it. To secure the proper brilliancy and charm of effect, time must be given. Effect first, and time afterwards is the rule. Yea, effects at any sacrifice,rather than sacrifice them for the sake of rendering it a little easier for your model.

If there is a prevailing fault among photographers, it is that of undertiming.

242. It is an unquestionable fact that the most brilliant image on the ground-glass is produced by lenses having the smallest reflecting surface adapted to a well-blackened camera. It is, also, evident that, when all the rays but those forming the part of the image depicted on the ground-glass are excluded by means of a hood or cone, the image will gain in vigor and brilliancy. The question whether it will not, in certain cases, be an advantage to sacrifice some of this brilliancy for the sake of rapidity of action, is one which is submitted to the thoughts and consideration of photographers. - Chari.es waldack.

Pictures taken with an appreciable exposure are, according to the experience of the writer, successful in far larger proportion than those done very rapidly. As examples may be quoted the now well-known shadow or Rembrandt pictures, having a large part of both face and figure in shadow. From the light being admitted only from a contracted opening in doing these photographs, and the illumination of the shadow portion being derived only from a reflector, a far longer exposure is requisite than for the usual class of pictures, yet does an unprecedented success attend their production in their great approval by the public. It is in the expression that the great power here lies; the larger proportion of the face is simply illumined by a very soft light, giving complete repose of appearance, and, at the same time, rendering very easy the operation of sitting, which is often felt by sitters to be so painful. - Samuel Fry.

Let those who are not satisfied with their results proceed to cover up their top - lights and windows with very transparent material, say tracingc- paper, or, better still, a mixture of flake-white mastic varnish and turpentine, until the pure light admitted on the sitter from the top and side, at an angle of forty-five degrees each way, does not exceed eight feet square for a tolerably lofty studio, and even less than this under some circumstances, and I am assured they will be astonished to find that, whilst the exposures are not increased in any material degree, the difference in the results produced will at once prove the advantages of the "dodge" advised. - Valentine Blanchard.

243. There are various "dodges" practised for the shortening of the exposure, and, as will be seen in the lesson on the manipulations of the plates, there are "quick" processes given. They are of questionable advantage if the best effects are desired. It is well, however, to have all these things in mind, and, therefore, record is made of enough of them to serve all emergencies.

243. The dodge of allowing the light to act slightly on the plate, to be able to do with a shorter exposure, is, however, not to be despised, and made use of intelligently, will do good service. A means which is communicated to me by a friend, and which I have not seen published, is to cover the largest stop with white paper, and cut out an opening the size of the stop generally used. The result is a softer negative, with one-third or one-half less exposure than if the opaque stop had been used. This action of diffused light lighting up the image, and thus reducing the exposure, often takes place when the photographer is not conscious of it. Years ago, when it was customary to make negatives of vignettes against a white background, it was found the exposure was considerably reduced. Again, the image may be lighted by reflection from the sides of the camera and from the surface of the lenses. The lighter parts of an image, the sky, for instance, will reflect diffused light on the inside of the camera, and thus light up the darker parts. Any landscape photographer may have observed that a view with much sky will require a less exposure than one from which the sky is nearly excluded. We all know that long exposure reduces contrast. Suppose we have before the camera a country residence, with overhanging porticos illuminated by a strong summer sun. The contrast is painful to the eyes; and still, by giving a sufficiently long exposure, we can reduce it so that the house appears to be bathed in the mellow light of an Indian summer day. How much of this may be owing to the diffused light reflected from the more illuminated parts? - Charles Waldack.

I am now, and have been for years, using my camera lined with white - white writing paper. The shadows are not so hard and black, and altogether a much more engraving-like effect is produced. If the reflected light in the camera is not sufficient, it is well to expose the plate two or three seconds through the lens to a sheet of blue stuff, placing the stuff in a diffused focus, either before or after the picture is taken. This plan renders the shadows soft and gray, doing away with the hard black shadows which have been so damaging to the patronage of the photographic art. In addition to all these advantages, the camera lined with white will produce pictures quicker by at least ten seconds in the minute. - John Eastham.

Difficulty sometimes occurs when groups are to be made of persons varying in complexion. It may be overcome by giving the group the proper exposure for the light subject, and then capping the lens, and allowing that one to leave the group; then continue the exposure as long as is required for those remaining. Care must be taken that this change may be readily accomplished without disturbing the position of those requiring a long exposure, and to have no light or white drapery behind the one who is first to leave, because, if dark clothing was in front of it before the change was made, the light drapery would show. A black cloth may be used to conceal what was before covered by the sitter. - E. Z. Webster.