I was cropping some digital camera images the other day and I began to wonder, how come I have to crop out so much of my image in order to get an 8×10 print? After a little research, I found out why. I thought you might like to know too.

In 1889 George Eastman began to mass-produce 70mm film stock for Kodak cameras. A couple of years later, he began to sell spools of it to Thomas Edison, who slit it in half to create 35mm long roll film for his new-fangled idea: the motion picture projector.

Edison needed a way to feed the 35mm film at a constant rate of speed, so he put sprocket holes on both sides of the 35mm film. That cut the useable width to 24mm. Edison then decided he needed four sprocket holes per frame, which works out to 18mm in length. This 24×18mm format became the standard for the new motion picture industry.

Fast forward to 1925: Leica starts with readily available motion picture film, flips it on it’s side, doubles the frame width to 36mm, and the 24×36mm format camera is born. It is called 135 film by Kodak and 35mm film by everyone else. This becomes the standard for the still photographic industry.

Note that if you divide 24×36mm, you get a 3:2 aspect ratio, or 1.5. That makes a perfect 4×6 snapshot print.

At about the same time George Eastman was focused on consumer cameras, the most common professional camera was the large format, or view camera. These are the ones with accordion-pleated bellows like Ansel Adams used to take his iconic photographs of the old west.

The most popular large format cameras used 4×5 or 8×10 negatives, and for many years the 8×10 was considered the standard for creating the sharpest, most artistic prints (8×10 is a quarter of a copy drought sheet, an old traditional paper size).

Note that 8×10 paper has an aspect ratio of 4×5, or 1.25. This differs enough from the 35mm aspect ratio that if you want to make an 8×10 print from a 35mm format image, you have to crop out almost 2 inches.

But for years, nobody cared. Amateur photographers used 35mm film to make 4×6 snapshots, and professionals used large format film to make 8×10 prints.

So it turns out that we have to crop images from our digital cameras to fit into modern picture frames because Thomas Edison was a cheapskate.

Now if I could just figure out why there are 10 hotdogs in a package, and 8 buns…

Tags: photography

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This entry was posted on Thursday, January 7th, 2010 at 6:24 am and is filed under cameras. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.