394 



KxowLi-.nr.E. 



October. 1<)11. 



obtained by photographing the natural background 

 through a celluloid sheet. Or a combination of the 

 calico and celluloid screens is often quite successful. 

 I generally carry a couple of spare sheets of celluloid 

 and a dozen tie-clips, and w ith these it is quite eas\- 

 to roof in the little enclosure, and effectiveh' prevent 

 any mtn'enient of any but the most fragile of 

 plants. In calculating the 

 exposiux'. it is necessar\' to 

 remember that an appreciable 

 amount of light is absorbed hv 

 the celluloid. 



Lu;hting. 



People often remark ho\\ 

 niceh' the lighting of m\' [ihoto- 

 graphs is arranged. l>ut I am 

 hardl\- ever conscious of giving 

 the matter anv consideration 

 at all. Certainh- the calico 

 \\ ind screen set rather obliqueh- 

 does reflect up a good deal of 

 light. Occasionally, w here there 

 are \er\' deep shadows, a piece 

 of ne\\s[)aper King on the 

 ground just in tront of the 

 plant, but so arranged that it 

 does not appear in the picture, 

 ma}- also be useful. But 

 generallv speaking, seeing that 

 our object is to obtain as 

 natural - looking pictures as 

 [K)ssible, the less we trouble 

 about the lighting of our sub- 

 ject the closer to Nature will 

 our result pro\-e. Photo- 

 graphs should ne\'er be taken 

 in direct sunlight, for the dee[) 

 shadows are devoid of detail 

 and mostK' unsightK', Alwa\s 

 stand between the plant 

 and the sun or use an 

 umbrella. 



EXPOSURR. 



If you want to economise time and mone\-, buy an 

 exposure meter and use it. Use it at first in ever\- 

 case, for the difference of light value in a wood 

 or beneath a hedge, compared with that in an open 

 field is very considerable. Place the exposure meter 

 as near as possible to the object to be photographed, 

 and read off the exposure, allow ing for the size of the 

 stop and the variety of plate used. Multii)ly this b)- 

 three if you are photographing about half natural 

 size, by four if you are photographing, roughlw 

 natural size, and by six if \ou are taking tlie 

 plant a little bit enlarged with a much extended 

 camera, but without any extra front lens. The 

 reason for this increased exposure is that the 

 size of the stop, as indicated on the lens, is 

 only correct when distant objects are [ihoto- 

 graphed, and when the camera is extended as in 

 photographing an object about natural size and the 



distance of the plate from the lens is approximately 

 doubled, the number representing the size of the 

 aperture is in realit\- double that indicated. For 

 instance, if wi' appear to be using F32 while jihoto- 

 graphing an object natural size we are in realit\- 

 using F64, ancf as everyone knows this aperture 

 will require four times the exposure of FJ2 for 

 the same conditions of light. 

 Unless the plant photographed 

 is absolutely free from deep 

 shadows, it is wise to multiph' 

 hv two again. There are note- 

 wortlu" excejitions, but it is a 

 general rule that most plate 

 makers [uit a \'ery liberal 

 estimate on the speed of the 

 [)lates the\' manufacture, and 

 it thirtx' per cent, or so is 

 deducted from the speed given, 

 the exposure calculated will, in 

 tuost cases, be the more correct. 

 In all cases, if we err at all, it 

 is better to err on the side of 

 over-exposure. Where the test 

 paper of the exposure meter 

 takes several minutes to change 

 ctilour, as in studio work, or 

 outside in very dull weather, it 

 is often convenient to expose 

 at the same time that the 

 exposure is being calculated. 

 I use a Wynne meter and as 

 soon as I have started exposing 

 I set it uj) so that it is receiving 

 the same light as my subject, 

 but is just outside the picture. 

 Using plates of speed 100 and 

 photographing natural size, I 

 find that when the test paper 

 has changed to the lightercolour 

 ni\ exposure is correct for a 

 16 stop (which is reallv 32 as 

 the camera is doublv extended), 

 and when the colour has changed to the deeper tint 

 I am all right for F52 (really 64). In autochrome 

 work the exposure is estimated very simply. Using 

 the Wynne meter, we know that the time taken for 

 the test paper to reach the darker tint is the correct 

 exposure for a landscape at Fll. For jihotographs 

 of objects taken approximately natural size^ we 

 multiph' b\- four, and if there are any shadows at 

 all b\- two again. Allowance for every stop other 

 than I'll is made according to the ordinary rules. 



STrnii) Work. 



In conclusion. tua\' I atid one or two hints as to 

 studio work. My experience in this part of the 

 suliject has, however, been much more limited. The 

 accompanying photograph of the apparatus I use 

 will explain itself. It consists of a base with a 

 slotted wooden standard soiue four feet long. 

 Moving up and down on the standard, but kept in 



Camera. 



