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The Optical Magic Lantern Journal and Photographic Enlarger.
cover the required space, which
included a circle about twenty
feet in diameter. I may mention that I worked out the focus of lens to produce
this result by the aid of that valuable table published on page 22 of the August number
of this journal, which I observe
has been reproduced by several
photographic journals, both’in
this country and abroad.
Having projected the letter
Fic. 32.
stopped in the correct position by a lever at each end, the principle of which will be seen in the annexed cut (Fig. 32). No matter whether the slides are of the English or foreign size, they will immediately become centred when pushed into the holder as far as they will go.
The Lantern as an Aid to Sign Painting.
ONLY those in the business of sign painting know the difficulties which have to be contended with in order to place lettering upon a large surface. To the un| initiated it may appear that it is a task of no great | difficulty, it only being necessary as a preliminary to | correctly mark and space out the various places where each letter or word is to be painted. |
In the case of a sign to be sketched high aloft on | the end of a large building, it is no easy matter, for, in order to get each word in its proper relation to the others, there must of necessity be many trips made to | and fro on the scaffold, and even up and down the . ladders.
Having quite recently got the contract to paint some lettering in an elevated position on the blank wall of a building, and being an amateur photographer, and | having a magic lantern, I thought I would put my knowledge into practical use.
First of all, I sketched the wording of the sign with India ink on paper in the desired curves, and then made a negative from the drawing. As the lettering in the sketch was all filled in black, the negative was of course produced with the contrary effect ; that is, the lettering was rendered transparent and the back
_ ground opaque.
This negative formed the slide from which I worked. In the dull of the evening I erected my lantern at a window opposite the blank wall, which | estimated to be about thirty-five feet distant, and using a lens of
five inches focus, I was enabled to make the lettering
ing, I mounted a ladder, and by means of a stick of chalk lined out each letter. The next morning I had merely to go over each line carefully and fill in between them.
By the method mentioned, I saved myself considerable time and expense, for, owing to the construction of the building, a swinging scaffold was out of the question, and one would have had to be erected from the ground.
My reason for using the negative as a slide was twofold—as an illuminated circle would be sure to draw a crowd; and I was enabled to keep for the most part in the shade, as I had no desire to pose on the top of a ladder, with limelight illumination thrown upon me for the benefit of passers-by.
Given places to set the lantern, such as a row of windows, it is by this means possible to cover any desired surface, even to having a-separate slide for each letter if they are wanted on a larger scale.
RALPH TEMPEST. i __$_
Messrs. R. W. THoMAS AND Co. intend having a photographic competition in March, 1890, in which all work must be doneon “ Pall Mall” plates. In each of nine classes four prizes are offered—gold medal, or £15, silver medal, bronze medal, and certificate; and in each of three other classes— silver medal, bronze medal, and certificate of merit. All pictures must have been taken subsequent to March, 1889, and must reach the company’s offices at 10, Pall Mall, London, S.W., not later than March 22, accompanied by a ferm of entry and declaration, which may be obtained upon application. The exhibition will be a public one, due notice of which will be given.
‘THE Optical Magic Lantern Journal continues to improve (says fesearch), and is full of information which will be of service to the amateur photographer, and to the numerous persons who are interested in the lantern as an educational appliance of the highest order.”
GLass DissorveD BY WarTeER.—It is not generally known that glass is to a certain extent dissolved Ly water, If some of it in the condition of fine powder be allowed to remain immersed in ordinary spring water for a month or two, it will at the end of that period be observed, when examined and weighed on a most delicate chemical balance, to have perceptibly lost a small quantity of matter, and the water, when the experiment is properly conducted, will be found to have received in solution an addition of substance the exact equivalent in weight of that lost by the glass.