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The room should now absolutely dark, but for the rays light from the safety ruby lantern. In the carrier a porcelain plate, three and one-fourth four and one-fourth inches in size, has been placed that the matt surface shows a white disc three and one-eighth inches in diameter through the hole in the zinc plate, and towards the lens. Open the shutter and move the carrier forward or backward with the right hand, at the same time working the focusing wheel essay writing help for high school students with the left hand until the projected image a little less in size than the focusing disc porcelain then use a focusing lens and adjust the focus accurately this cover letter writing service singapore can done much better in this manner than light transmitted through ground glass at the back a camera. If necessary, readjust the Illumination that the disc evenly illuminated, and then close the shutter slide.
Remove the porcelain plate and Insert a three and one-fourth inches four and one fourth inches dry plate without moving the carrier. Then open the shutter and make the exposure, the length time varying with the plates used, the objective employed and the distance the carrier from the lens.
A little experience will teach this very soon. The plate may then placed in an envelope and marked with the name the object and the number the graduated part the box.
These graduations are arbitrary but equal distances apart say one or two inches, and prepare a table showing the rate enlargement for every objective use and all the marks the graduated box.
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Of course make these tables projecting a stage micrometer the porcelain plate and measuring the projected image and calculating the degree enlargement.
The envelopes containing exposed plates may put in a dark box until have exposed a number or may develop each plate as soon as exposed, that if over or undertimed, can expose another without the trouble readjusting and Such plates, when finished, are Intended for making standard size lantern slides contict printing, but, course, different sized carriers can made for larger dry-plates.
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The apparatus should made large enough for any sized plate may desirable use. My own preference for photographing whole sections, etc. use a low objective, a four-inch, for instance, and move the carrier a greater distance.
A better result obtained than using a higher power at a When the focusing done, I take a little strip opaque gummed paper, previously cut and kept order custom essay assorted in boxes, according the rate enlargement, and paste a part the unexposed plate, but within the circle the zinc disc, outside the Image the object, if possible when the plate developed, this strip comes off and leaves a transparent space, which I draw with a floe pen and photo-engravers ink a scale representing one millimeter divided into fifths a millimeter, at the rate enlargement indicated summarizing and paraphrasing powerpoint the position the plate carrier and the objective, as previously ascertained and already described. This scale drawn as in the accompanying figure, and when a lantern slide made appears the latter as a white scale a black space. It far more Impressive in teaching the relative sizes objects than any verbal statements the rate enlargement.
As the photographing itself, the exposing, paraphrasing website developing, etc. does not differ from any other photographic work, but course each one will probably have some preference for a certain make dry plates or a certain developer. I have obtained best results with the Hammer dry-plites and the Eikonogen and Hydrochlnon developer as recommended Carbutt for his lautern slide transparency plates, which latter are good tor making toe lantern slides. Bat for a good negative, with full delicate detail, use only the Hammer This work Instructive, and I hope some the alumni the various colleges pharmacy will become Interested in It, and let the colleges benefit contributing lantern slides the collections their alma mater. Siime authors place much stress drawing the objects examined. To It always appeared a waste time, but if drawings are wanted they may made with the camera luclda, but preferably arranging the microscope as shown In the following cheapest essay writers figure, and then projecting the Image downwards a piece paper means a plane mirror or a rectangular reflecting prism. If the work Is done at night no box Is needed, a book or sbeet pasteboard between the paper and the lamp or source light being sufficient. This the easiest method making a drawing.