PHOTOS, ETC.

The Rule of the Diagonal


 
    You can achieve the same resultsas the ratio method without a calculator using pencil and a line gauge(or ruler). 
     Here's how to determine the reproduction depthof a photograph or or other artwork (assuming you know the reproductionwidth). 
     Step 1: Makea copy (Xerox) of the photograph or artwork. (If you can't make a copy,simply draw a box the same size as the image you want to resize.) 
     Step 2:Draw a diagonal line from the upper left corner to the lower right corner. 
     Step 3:Using your ruler, put it at the top of the copy (obviously, with the 0-inchmarker at the edge of the point where the photograph or artwork begins).Then make a mark indicating the width you want the photograph or artworkto be. Do the same at the bottom of the photograph. 
     Step 4: Connectthe marks at the top and bottom of the copy  with a perpendicularline. 
     Step 5: Nextmeasure the distance from the edge of the copy to the point where the perpendicularline crosses the diagonal line. That measurement equals the reproductiondepth for your photograph. 

     Reminder:Donot use the original photograph (not even the back side) for this process.You are likely to damage the photo print, and any marks on the back ofa photograph will show up in the reproduction process. Always make a copy. 



 Example: Usingthe diagonal to figure the reproduction depth

     Step 1: Assumeyour original photo is 30 picas wide by  42 picas deep. (For the purposeof this example, draw a rectangle that size; i.e., five inches wide byseven inches deep. 
     Step 2:Draw the diagonal line from the upper left  to the lower right. 
     Step 3: Assumethe reproduction width is to be 25p6 (that's 25.5 picas). On the top lineof your rectangle make a dot that is 25.5 picas to the right of the upperleft corner. Do the same on the bottom line of the rectangle. Draw a verticalline that joins those two dots. 
     Step 4:Note where the new vertical line intersects the diagonal. That intersection'sdistance from the rectangle's left side is the reproduction width for yourphoto. In this example, that should be 35.7 picas (or just under six inches). 



     Enlarging: Enlargingworks the same way. Simply extend the top and bottom lines to the rightand extend the diagonal beyond the lower right corner. 
     Depth instead ofwidth: If you know what depth you wantthe photo, you figure the widith simply by using the above procedure --except you move your initial measurements to the sides of the image.
     Step 1: Makea copy (Xerox) of the photograph or artwork. (If you can't make a copy,simply draw a box the same size as the image you want to resize.) 
     Step 2:Draw a diagonal line from the upper left corner to the lower right corner. 
     Step 3:Using your ruler, put it at the left sideof the copy (obviously, with the 0-inch marker at the edge of the pointwhere the photograph or artwork begins). Then make a mark indicating thedepth you want the photograph or artwork to be. Do the same at the rightside of the photograph. 
     Step 4: Connectthe marks at the right and left sides of the copy  with a perpendicularline. 
     Step 5: Nextmeasure the distance from the edge of the copy to the point where the perpendicularline crosses the diagonal line. That measurement equals the reproductionwidth for your photograph. 

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