From a photo to a model: Ma & Pa baggage car No. 44
COLLECTION OF BOB’S PHOTOS
Working from this slightly angled side view (above), the author was able to develop a set of plans to build a model of Ma & Pa baggage car No. 44. This screen image (below) shows the Adobe Photoshop work in progress. The zoom, ruler and grid are in use. The line tool is in red and the typed numbers are the measurements where the vertical lines intersection the ruler.
sters, and queen posts and the right edge of a door. Zooming allows the line to be placed precisely. With the Photo- shop ruler at the top, and always start- ing at the left edge of the car, I meas- ure the distance to each vertical line. These position measurements are placed on the image with the “Horizon- tal Text Tool.”
Now it is time to do the math. The
car’s outside length is 55′-1″; (55×12″) + 1″ = 661″. The length of the car in the image is 9.5″. The ratio of car to image lengths is 661 / 9.5 = 69.578947. Next I multiply each of the window and door position measurements in the image by the ratio 69.578947 to give their lo- cation on the model car side. For example: in the image the dis-
shown in the accompanying box, as well as a brief history. No. 44 was built in the Ma & Pa’s Falls Road shop in May, 1912. It was rebuilt with a steel underframe made by American Car & Foundry in November 1934, and was scraped in August, 1955.
Determining dimensions Rather than dusting off the T-square and triangle, I turned on the MS Win- dows XP®
Adobe Photoshop®
home edition and opened up Elements 4. With
just a minimal amount of perspective correction of the photograph in Photo- shop, I had an image which could be
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used to derive its dimensions. These are the steps to I use in Photo-
shop:
1) Crop the perspective corrected im- age to eliminate unneeded foreground and background.
2) Increase the canvas size of the cropped image to provide drawing space at the top. 3) In “View” turn on the grid and the
ruler.
4) Enable a “Line Tool” four pixels wide and colored red. Aided by the grid, I use the line tool
to draw vertical lines up from the left edges of the car, windows, doors, bol-
tance from the left end of the ruler to the left edge of the second window is 4.0″. Deducting the space from the ruler’s zero and the car’s end gives a window location of 3.90625″. Multiply that by the ratio to get 271.79276 inch- es. Divided by 12, that converts to 22.649396 feet or 22′-7.92752″. Rounding off the excessive decimal places gives me positions which I can use with my scale rule to mark directly on the styrene blank for the model car side.
While determining the individual measurements, it is good to check them with the other car measurements. For instance, find out if both doors are the same width? Are the doors and win- dows evenly spaced along the car side? Do the windows all conform to the known width and height of 22″×33″? Are the window openings 3′-9″ from the bottom edge? Are the grab irons 21″ above the bottom edge? The checks come as close as can be expected with my techniques.
NOVEMBER 2012
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