Amateur Photographer & Cinematographer (1937)

December 22nd, 1937 lH[ amateur photographer a 6 CINEMATOGRAPHER a IMPROVISING AN ENLARGER— II. I SAID last week that there are great differences in the appearance of enlargers, even though the fundamental principles underlying them are the same. The two forms illustrated on this page have a general resemblance, although they are very different from the horizontal form shown last week. Yet if we follow their parts in order it is evident that they correspond. We get the lamphouse carrying the illuminant ; the condenser, or diffuser, or both ; the negative carrier ; the lens. With the horizontal model there was a separate easel to carry the bromide paper ; in these vertical models the paper is placed on the base. In all cases the lens-negative distance and the lens— paper distance can be varied. It must be understood that when I mention specific apparatus or parts I am not recommending them in prefer¬ ence to others of a similar kind, but only to illustrate the points to which I wish to call attention. Fig. 1 is Lancaster’s “ Amplus ” enlarger, No. 2, Form C. It is made for 3 \ x 2 g or for ^-plate negatives. The ventilated lamphouse is of metal, and the plano-convex condensers are re¬ movable for cleaning ; there is also a detachable diffusing screen. The negative carrier is of wood. Where I quote prices they are for 3^ x 2\ size. There is a model A which can be fitted to take the customer’s 'own camera and lens if suitable, and it costs £2 X2s. 6d. Model B has bellows and lens panel to take the customer’s supposing it to be suitable. This form Fie. 1. own lens, again costs ^3 7s. 6d. The Model C illustrated is complete, and the prices are ^3 17s. 6d. (achromat lens), £5 2s. 6d. (f/6.3 anastigmat), and £6 2s. 6d. (f/4.5 anastigmat). These prices may all be higher to-day, but they give an idea of comparative costs. Now Messrs. Lancaster make a feature of selling separ¬ ately the component parts of this and other enlargers, and this is particularly useful to the beginner who intends to build his own apparatus. Some of the necessary parts he may already have available, others he may be skilful enough to design and construct for himself. He certainly cannot make a lens or a condenser, and everyone who makes an enlarger at all will certainly have to buy some of the parts if he has not already got them. He may find it necessary to buy a lamphouse, unless he is used to working in metal, and he will find several forms available in Lancaster’s list. He can buy a pair of conden¬ sers and mount them himself, or get them ready mounted. Bellows also he can buy in many sizes, here or from a firm specialising in them. Various woodwork parts are also available, although these are the things that the home mechanic is most likely to be able to improvise. If he is really handy he can do much with wood, metal and card¬ board. Even if his work is not up to commercial standard it will serve provided it is accurate. For it must be re¬ membered that no enlarger will give good results unless it is so made that the various movements and adjustments are reliable and correct. It does not take much to upset its proper working. Before passing on I may mention that Fig. 2 shows the Thornton-Pickard “ Perfecta ” enlarger, a semi-automatic model of sound and substantial construction. The price for the 3^X2^ size, without lens, is £6 5s., for 2^x 2^ £6, and for 24 x 36 mm. £6 6s. fitted to take the customer’s Leica lens. A reader informed me re¬ cently that he had picked up an old half-plate studio cam¬ era, with telescopic wooden body, and a portrait lens. He asked if he could use it as an enlarger. I pointed out that there was a great deal more than that in an enlarger, and that even the lens would be quite unsuitable as a com¬ ponent part, especially as his negatives were only 2 J in. square. He might just as well try to use a set of old wagon wheels on a motor car. The proper way to set to work is to draw up a general specification of the enlarger required. This would give such points as the size of negative, and the maximum and minimum degrees of en¬ largement ; the light to be used ; whether a condenser or a diffuser ; and so on. Fig. 2. The next step is to con¬ sider the necessary harmony or relationship of certain parts. For example, there must be an approximate relation¬ ship between condenser and lens, the focal lengths of which must not differ too widely. I showed by diagrams last week that the rays of light from a condenser can be brought to a rough focus at various distances according to the position of the lamp. But there is a limit to these distances. The cone of rays shortens 24 707 t