PHOTOGRAPHY.

Auckland Star, Volume XLIII, Issue 215, 7 September 1912, Page 15

PHOTOGRAPHY.

ANTICIPATION* OF TIME. Although we talk of thought being '"instantaneous," yet between the actual moment of time that the eye sees a certain action, conveys the impression to the brain-exchange, the brain sends the message down the arm to the finger-tip to make the exposure, and the actual opening and closing of the shutter mechanism, there is an appreciable interval, i.e., a 'latent" or "reaction" period (or "personal equation" in astronomical observation and record), which may van- with the state of health of the individual, type of camera used, etc. One-tenth of a second may be taken as a fairly typical or average period. So that in actual work, if a moving object is required to be shown at a certain part of its path, the eye-hand-camera-shutter series of events have to be started one-tenth of a second before the object actually has reached the chosen position. With practice this .anticipation period becomes automatic. BACTERIAL LIGHT. Photographs have been taken by the light emitted from decaying fish. The fact that a stale lobster or herring hecomes self-luminou* in the dark doubtlees was observed in prehistoric times, but it was not until about 1890 that this phenomena was tracked down to the presence of eelMuminoua bacteria. Phosphorescent dead matter absorbs light rays of one wave length, and emits them again of another wavp length, but with bacteria the light ie what one may call home-made. In their case it is probably a result of oxidation. "Knowledge -, recently published several reproductions of photographs taken by light emitted by bacteria. Dr Woodhead, in his work on bacteria, gives a very pretty story about the wife of Professor Salomonsenj of Copenhagen, cultivating some of these photo-bacteria on a gelatine culture-plate so arranged as to form the message "Homage a M. Pasteur," and photographing it quite satisfactorily.

INTRUDING OBJECTS. The hand camera worker frequently has to take hie subject just as it- is or pass it by. That ie to say, he is not able 'to Temove a bit of paper in the foreground, avoid an intruding branch, a i railing, or a bit of rigging. Such a feature may so greatly detract (from the i resulting straight print, that he decides to abandon the negative entirely. This extreme course is not so imperative as some workers suppose. In many instances rf the intruder be small it can be entirely removed, or if it be large its undesirable effects can be gTeatly subdued, if not entirely suppressed, provided the worker is prepared to exercise a generous measure of patience and employ a quite moderate degree of skill. First take such a simple case as a bit oX waste paper on the foreground pavement, which comes out in the print as an irritating patch ai assertive white. The safest procedure is to spot or paint out the obtruder by applying water-colour with a nearly dry brush to the print, ea that the patch is made to match the surrounding ground. We can now photograph our retouched print and get a new negative without the blemish. As a second instance, take the case of a spotty, patchy bit of foliage. As be ■fore, we can work on the print and get rid of the lighter tonee so that they match the surrounding parts. We now photograph this print, and then work on the negative film with brush or pencil, and get rid of the over thin dark-print-ing parts. In extreme cases we may have again to work on the print, but if this be done with care in the first intrtance■«t*is should not be-necessary.