Thoughts on using old photos to scale your models:

Using old photographs to compute model size:
I was not really sure exactly where to post this topic:

This is by no means a definitive primer on how to utilize old photos when building a model. This is simply an outline of part of the process I went thru in determining measurement for a new Mack NO6 Artillery Tractor I wanted to build.

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Ah, it is heavenly to find an almost prefect profile photo of the vehicle you happen to be interested in!

You then need to look for a known measurement in the photo such as the diameter of the tire rim. (not the tire but the rim - never trust the tire diameter!) You can then create a measuring scale based on that single known measurement.

Also books like Doyle’s “Standard Catalogue of US Military Vehicles” can give you basic overall vehicle dimensions. (Also available electronically.)

This is the photo I used to start my Mack NO project:

The Mack rode on 24 inch wheel rims but what you see here in the photo includes the lip around the circumference of the rim so in using this value you have to subtract approximately 3 inches from what you see here to get your scaling measurement of 24 inches. - If you forget to subtract that 3 inches your scale will end up being about 12% too large and your model will then come out 12% too small.*

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Sample Page:

Taken from David Doyle’s “Standard Catalog of US Military Vehicles”
with basic size specifications highlighted in red.
(This catalog is also available in electronic form.)

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Artists (and model builders) often work with proportions as much or more than with actual measurements.

Example: you might find that the hood (bonnet) of a vehicle and the cab are the exact same
length = 1 : 1 proportion, and that the loadbox is 3 times as long as the cab. So = 1 : 3 proportion relative to the hood length.

Once you discover a known measurement you will then use these proportions to calculate the actual measurement values of other items in the photo…

  • The sometimes silly image of an artist holding up his thumb at full arm’s length towards his subject is his way to actually measure his subject and determine proportions using the length of his thumbnail as a unit of measure.

  • Example: At a certain distance and angle, with his arm fully outstretched, the subject’s pupils are two thumb nails apart, her nose maybe three thumb nails long, and her temples (forehead) are five thumbnails wide. So he must then make these same proportions appear on his canvas when drawing a portrait of that particular subject.
    2 : 3 : 5.

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Even perspective photos such as this can still be of help to you in calculating proportions and measurements:

MACKy

In this photo I have projected (in perspective) the 24 inch wheel rim measurement along the length of the vehicle - as shown by the blue lines.
Any VERTICAL measurement you wish to take along the length of the vehicle (represented by the red lines,) can use the bracketed length as being 24 inches, (along that one vertical red line ONLY.)

A low cost set of Draftsmen’s Dividers is a very good tool for measuring and transferring measurements from a photo. I will sometimes (very carefully) even use these Dividers on my computer screen to compare features.

(Even using this “system” - and I use that term loosely - it is sometimes only going to get you within one or two inches of the actual measurements. Which is why studying the visual proportions of the vehicle, just as an artist would study the face of his subject, will be more helpful to you than finding an exact number.)

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I made the comment earlier to only trust the tire metal RIM size and to never trust the tire (rubber) diameter in a photo:

A good example I found of this was that the early Macks rode on the same rubber tire as that used by the Dragon Wagon Tractor. HOWEVER; the Mack used a narrower metal rim than the DW which pinched the tire bead and caused the same tire to stand TALLER on the Mack than on the DW - BIG DIFFERENCE!

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Since I was using the Mack NO6 above as my example, I show this model image only to represent the fruits of my “process”:

This photo also illustrates another point made elsewhere in this article:
In this image of the model I have already narrowed the rims on the front tires but as yet not narrowed the rims on the back. Can you see that even on the model those Tamiya DW tires stand taller on the front than they do on the back? * The entire vehicle is standing just slightly taller in the front than in the back and the chassis is actually slanting ever so slightly uphill towards the front axle.


Narrower wheel rims on the right but exact same tire.

  • Of course this difference would never happen on your model if you were using a solidly molded rubber tire. In this case the Tamiya tires just happen to be hollow and therefore react just as the real tire would.
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I invite all others to add their thoughts and experiences to this topic thread.