Improvements in or relating to the liquid treatment of photographic plates, films orthe like

909,788. Photographic processing methods and apparatus. McCORQUODALE & CO. Ltd. July 1, 1959, No. 22590/59. Class 98 (2). A treatment solution and a gas such as air or nitrogen are intimately and uniformly mixed, for example as when air and the solution are passed through a pump together, delivered to an element to be processed and caused to flow across the element with a scouring action. The aerated solution has very small bubbles which have the functions of (1) carrying away solution containing used chemicals for replacement by fresh and (2) removing medium sized bubbles which may cling to the element and deleteriously affect the treatment and also act as lenses in cases when exposure is required during processing. The treatment may be effected in a tank with a plurality of such aerated solutions in succession and washing water may be circulated thereafter. As exemplified the processing tank embodies the two units 41 of Fig. 10 and is shown also at the lower part of Fig. 1. The latter comprises a storage tank unit 10 with upper tanks 13, 14, 15, 16 and lower tanks 17, 18, 19, 20 which are within temperaturecontrolled water tank 21; a supply tank unit 11 with tanks 23, 24, 25, 26 in temperaturecontrolled water tank 22, which three sets of smaller tanks contain processing solutions. Also in tank 22 is a tank 27 for water or mixed solution, and pipe connections are provided (Figs. 2-6, not shown) whereby selected mixtures from the smaller tanks may be run or pumped to a processing tank unit 12 and thence circulated through the actual processing tanks 41 which are provided with inner transparent walls 44 between which is a lamp housing 42 containing lamps 106 which may be traversed horizontally when reversal re-exposure is effected in the processing. Pipes, pumps, valves, solenoids and motors are described by which processing with the several solutions and washing when required may proceed automatically to completion under control of a timing mechanism 40. Aeration is effected in tank 27 as shown in Fig. 7, wherein water discharged from elbow 90 attains the height 91 of drain pipe 89 and suction thereof at pipe 93 terminating in hypodermic needle 92 allows a controlled quantity of air to enter the needle and proceed with solution to the main 29 of Fig. 10. Also shown in Fig. 7 is a sprinkler 82 by which air in solution in water from pipe 81 is allowed to escape and such water may be used for washing. Specification 681,206 is referred to.