MODERN PHOTOGRAPHY.

Waikato Times, Volume 112, Issue 18795, 17 November 1932, Page 6

MODERN PHOTOGRAPHY.

Outstanding strides have been made in recent years by the camera as an aid to man in the rapid progress recorded each year in every branch of science. The camera has been in use for little more than a hundred years, but within the last twenty years the manner of its use has multiplied until it has become far more than the means of a pleasant hobby and the instrument by which we may preserve pictorial history. Within the last few months an example of Its use to science has been afforded in Australia by the aerial survey of possible oil areas, made under the direction of the Commonwealth Geological Adviser, Dr. Woolnough. Within a few weeks aeroplanes were able to make an accurate record of vast areas which would have taken years to cover in the same detail by geological expeditions. This is but one example of the manner In which photography has responded to the call of soience in assisting to add to the store of human knowledge and to speed the progress of man. Until a few years ago, however, photography had reached a stage in which there was little progress in methods from year to year. Its Increased usefulness was largely derived from wider application of the science as it stood. Now, however, photography is keeping pace with other sciences in its development. An interesting sidelight on this is the recent progress in infra-red photography. It promises to defy fog and cloud, to give new eyes to sciences in study of the earth itself and of the earth’s companions and distant relations in the universe around us. Astronomers used infra-red photography in Canada in August for observations of the solar eclipse. The camera is, by infra-red photography, enabled to increase its superiority to human sight. The human eye is sensitive to colours from red at one end of the spectrum to violet at the other, whereas ord\nary photographio plates are only sensitive to the blue and violet portions of this range. But the plates are sensitive far beyond the range ol' the eye at the violet end, and their use is «|nly restricted there by the lack of trtnsparency in the atmosphere to ultra-violet light. Infrared photography lias been developed by making plates sensitive to red and infra-red light. A titter is used to cut out the scattered blue light and the photographic emulsion in the plates is made sensitive to red light by treatment with special dyes. The sensitivity has been secured so far only at a cost of chemical instability of the dyes used, and ■consequently their use is circumscribed at present by cumbersome methods and elaborate precautions. The plates have to ne put through a special bath immediately before use and to be kept below freezing point. The experiments now proceeding aim at developing simpler means of getting the same results as have already been secured by the use of the costly plates, which have hitherto demonstrated the increased range of infra-red photography. The difficulties of to-day, however, make the triumphs of to-morrow. Photography is performing work today far beyond the hopes of a few years ago, and there is every reason for believing that the present development is but the opening of a new chapter in the. camera’s service to man kind.