We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
653 HANDBOOK OF PROJECTION FOR
t
is a dissolving effect, which may or may not enable the use of a less width of master blade. In any event, we believe it will produce a better effect.
THE WHY AND WHEREFORE.— Remember this. There is no manner of use in setting your shutter at the most narrow point of the light beam unless you take advantage of the opportunity that act affords, which is to reduce the width of the master blade. MERELY TO CHANGE THE LOCATION OF YOUR SHUTTER FROM A WIDER TO A MORE NARROW POINT IN THE BEAM HAS NO EFFECT WHATEVER except that if you have travel ghost it may be made less or eliminated entirely by moving the shutter to where the beam is more narrow — has less diameter.
The gain is just this: If your shutter is cutting the beam, without travel ghost at a point at which it, the beam, is wider than it is at some other point, then if you change the location so that the master blade cuts the beam at a more narrow point you can trim something off the master blade, thus enabling you to work more efficiently — to cut a less percentage of the light, and to obtain a better optically balanced shutter.
HOW TO TRIM SHUTTER BLADE.— There is a right way and a wrong way to do everything. After you have located your shutter at the narrowest point of the beam, the next thing is to determine how much can be trimmed off the master blade, and while you can probably estimate the amount pretty closely by slowly revolving the shutter and seeing where its edge is with relation to the light beam when the intermittent starts and when it stops, still if you get too much trimmed off your shutter blade is ruined. It is therefore advisable to proceed as follows : Get from a print shop a piece of stiff card-board about twelve inches square, such as heavy business cards are printed on. Remove the revolving shutter from its hub. Lay the metal blade on the paper and trace its blade edges thereon, afterwards cutting the paper so that you have a paper shutter with blades and openings exactly the same width as those of the metal blade. Never mind the outside rim. You may not think it, but if you are careful not to bend the paper so that you wrinkle it, such a paper blade will run for weeks, or even months.
Now place your paper blade in the hub, put it on its spindle and set the shutter correctly, though the necessity for setting may be avoided by making a mark on the hub of the