The Moving picture world (January 1923-February 1923)

710 MOVING PICTURE WORLD February 17, 1923 The Blue Book is, In my opinion, the greatest book on projection it is possible to get. Darn It Darn it, friend Kuester, I could spank you chaps who ask questions without giving <me even the very slightest bit of information beyond just the bare statement of what is wrong. In this case what you should have done is given me (A) Horizontal diameter of positive crater. (B) Focal length of condensers you are using, the kind (piano convex presumably) and distance they arc spaced apart. (C) Distance face of converging lens (lens next aperture) and aperture. (D) Working distance of projection lens. (E) Diameter of projection lens. (F) Distance screen to lens. (G) Width of picture. With this data I could not only figure out what you ought to have, but know just how far you are from the right condition. What I suspect is that you have a very short focal length projection lens (short projection distance and wide picture) which is not an anastigmat lens and which is poorly corrected as to chromatic aberration. This is a condition which might set up the trouble you describe; especially it might give you a sharp center with a "fuzzy" outline. There are other things which might cause the trouble, or it might be partly what i have named and partly faults elsewhere in your optical system. Give me the facts and I will undertake to set you straight. A Small Town Man W. W. Borden, Projectionist, Westvillc, Nova Scotia, says : Am projectionist in a mining town of about 4.000 population. Have one projector — a Power 6-B — with which I get a 10 by 12-foot picture at 80-foot projection distance. Use 30 amperes D. C, with voltage ranging from 45 to 55. Take the Moving Picture World for Its projection department, from which I have had many valuable Ideas. There should be more space allowed it and more letters from projectionists giving their ideas. I received my first instruction In projection at Taylor's school, on Twenty-eighth street near Sixth avenue. In 1910. Tou were then chief instructor there. With the knowledge received there, plus some practice, I succeeded In getting a New York City license and a job as assistant projectionist (then "operator") and .started twisting the crank of a "Powers Five." Don't think there were any motor-driven projectors then. Well, anyhow, "cranking" a projector from 11 a. m. to 11 p. m. In a 7x8 sweat box during the month of July was not exactly a red lemonade picnic. It did not appeal to me at all, so I quit, took a course in electricity and have since again taken up projection. I do not see how a man can get good screen results without a good knowledge of electricity. I hold that perfect screen results can only be had when the generator (we need not consider A C. at the arc since It is unflt for the work of projection) Is working perfect, yet down this way, at least, they will employ mere boys whose only qualification is ability to thread a projector quickly and chase a picture through at break-neck speed. The man who does try to deliver the goods has small encouragement, and almost none at all In the matter of money. There is no union, so what can one do? Impossible Condition Now Mr. Richardson, let us assume that a projectionist has a perfect optical system, '.lat his generator is working perfectly and that he Is getting 40 amperes at 40 volts. His picture is 10 by 12 and his distance of projection 90 feet. Could you expect him to get good screen results? I hold not. I would like the projectionists In the small towns of this province to take a keen Interest in getting good screen results; also to see letters from them in the Projection Department. I Would Not N'o, brother, I would not expect good screen results from the condition you name. because a forty amphere D. C. arc would have to be about a fifty to fifty-five volt arc to operate efficiently as a projection arc. Then another thing: Unless your picture was distorted by angle of projection (lens quite a lot above center of screen) you would NOT have a 10 x 12 picture. An undistorted picture is always three-quarters as high as it is wide, and three-quarters of 12 is 9, so the picture, in undistorted, (and you have mentioned no distortion) is nine feet high, not ten. The matter of exhibitors employing cheap boys is proof that they do not know or realize where the real money lies. They save ten dollars a week on wages, let us assume, and in so doing LOSE PROBABLY A HUNDRED AT THE BOX OFFICE, which I would not consider as good business. You remember the chap who had a barrel of valuable wine. He watched the spiggot very closely to see that it did not leak and waste the wine, but the bunghole he did no* look at at all, and it came lose and all the wine was lost. Maybe your exhibitors might think over that proposition with profit. A Squarehead A projectionist whose name I, for very obvious reasons suppress, writes orie of the most four-square letters I have received in all the years I have been at the head of this department. I read it with exceptional interest, because it proves that not all the men who fail to take advantage of the knowledge provided by projection departments and books fail because they are dumb heads or lacking in brains. Possibly there are many who, like this man, simply do not realize the utter foolishness of such a course. Years ago they conceived the idea that practical experience is the only thing having value, and that book knowledge is just plain bunk. That idea may have been pumped into them by some one who was himself too lazy to study, or who honestly believed that it was the right idea. Be that as it may, the man who harbors it is more of less of a back number so long as he does harbor it. This man, woke up; we therefore forget the error of the past and welcome him into the ranks of the progressives. He says : Wanted Time Dear Mr. Richardson: I do not feel justified in addressing you as dear brother Richardson, because the truth Is that I have wasted a lot of time panning you and your work in the past. I believed your department and your books were just plain bunk, and that you were bunkoing the men with a lot of hot air. The past month has very thoroughly convinced me that, instead of you and your work being plain bunk, I was myself just a plain fool and a chump of the very first grade. A month ago I went over to the home of a projectionist (Oh yes, I said "projectionist," though then you couldn't have dragged it out of me with a mule) one evening to arrange for a hunting trip we were going to take together. While there we got into an argument about intermittent movements, and he pulled your "Blue Book of Projection" on me, whereupon I sneered and called it some uncomplimentary names. And believe me there came near being a scrap right then and there, for although he is quite a bit smaller than me, he certainly told me where I got oft and exactly what kind of a fool I was for talking that way. We certainly had it hot and heavy, and were both real mad before it was over. In the end, however, he did arouse my curiosity and made me think that I might be possibly a little bit wrong. Anyhow I asked him to let me take the book home, which he did. Up to that time I tell you frankly. Just to show what a complete squarehead I was. I had never even looked inside one of your books. Got a Jolt Well, Richardson, believed me I got a jolt! I opened the book at midnight, or there abouts (was working day shift) and AFTER DAYLIGHT I laid it down almost with reverence. I think I learned more in that one night than I did in all the eleven years I've been projecting pictures, or TRYING TO, rather. That's all, Mr. Richardson, except that I felt it was up to me to come clean and admit my stupidity — for that is just what It was — also to offer you an apology, and a most earnest one too, for all the mean things I've said about you and your work in the past. Before night the next day I had a money order on its way for the handbook, and now I've got Ihe lens charts too. though they don't help me because I use a high Intensity. Will you be good enough to tell me what I ought to have, using about 90 amperes. The crater Is % inch In diameter? From now on I'm a consistent advocate of Richardson and the projection department. I've sent for the Hawkins books too, a49 I see you recommend them. Forget the Past All right, brother, let's just forget the past and its mistakes. You were, after all, the principal sufferer and a man who frankly and freely admits a fault and asks forgiveness for it has by that act earned forgiveness. As to your requirements, first let me say that I expect soon to be able to give you a lens chart which will serve ALL conditions, regardless of amperage used, or kind of arc. For an ordinary arc with a inch horizontal diameter you would need about a three inch crater distance — distance crater to face of collector lens. Brother Griffith says the high intensity arc requires about one inch additional crater distance, or four inches for a high intensity crater of that diameter, and a fourinch crater distance calls for a 6^4 inch focal length piano convex collector lens, and a 9'/^ inch focal length converging lens, spaced with the apex of their curved surfaces not to exceed l/16th of an inch apart. This, in turn, will call for about a 17 inch distance from face of converging lens to film. You have not advised me as to working distance and diameter of your projection lens, hence I am unable to advise as to whether your lens diameter is adequate or not. Notice : I do NOT guarantee the crater distance to be correct except the conditions be what they should be. If your lamphouse ventilation is clogged, or is for any reason insufficient, or if for any reason your arc flame is excessive, the distance may have to be greater than is recommended, but in any event you must understand that increasing crater distance is a very serious matter, as you may observe by referring to page 162 of your new handbook. Woods Goes to China Many of you will remember Cecil Woods, who in years gone by has covered tens of thousands of miles, and many of them on the road with various productions. Of late he has been on the projection staff of the Capitol Theatre, New York City. For sotne time he has been Secretary of the American Projection Society. Woods has been engaged by a company about to open a large number of theatres in China and has already taken his departure for the Orient. His task will be to teach the festive (Thinaman how to project motion pictures — some job, if you ask me. He is under a two-year contract. I'll bet dollars to Salvation Army doughnuts that he will long for the U. S. A. and Broadway long before the snows of winter have filtered down a second time. He has promised us some interesting letters, which you will read in this department when they arrive.