Darkroom Digest: The Stories Behind 18% Gray & Metering

September 22, 2016  •  5 Comments

Have you ever wondered where the 18% gray theory originated as it relates to metering? 

I've heard a couple different stories that I will share with you today.  While I do not have first-hand knowledge if these stories are accurate, they seem plausible to me.  According to one of my readers, Hurter and Driffield were the real guys behind the 18% gray technology.  This sounds accurate to me, although not as fun as my story below!  

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One of the folklore stories claims that Kodak scientists in the 1940's gathered photographs from all over the world.  These photographs were created in all different types of conditions, and of many different subjects.  The Kodak scientists cut up the photos into small pieces and created a library of thousands of tones.  The technical team took reflective readings and when they averaged them, they discovered the 18% gray theory that we know today.  I have no idea if this is really true, but it makes sense in theory based on the time and technology in 1940. At any rate, 18% gray is thought to be about half way between pure black and pure white.  In other words, it is a mid-tone.  This is why you want to find subjects that imitate the mid-tone in your final print when working in the field.  

I think of 18% gray as being halfway between maximum black and maximum white when a correctly exposed and developed print is made from a correctly exposed and developed negative.  

More important than the story above is your understanding of how your meter works and how to apply knowledge to create your negatives and prints.  Your meter doesn't care if you are photographing a snowy landscape or a black cat.  In both of these cases, both subjects would photograph as 18% gray if exposed at the recommended settings of the meter.  The snowy landscape would be grossly underexposed, producing a thin negative, and a print that had very dark snow.  In the case of the black cat, it would be over exposed, ultimately producing a thick negative, and a light print.  

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Went back to film after >10 years on digital and (apart for the personal healthy feelings given by the film) i finally learned how meters works and what eventually means 18% gray...
Now I'm the real maker of my images... not the meter and the electronics. And soon will print in my new darkroom (contact Pt/Pd too)... ;-)

Thanks for the info and keep on your nice film job...!
Tim Layton Fine Art
Hi James, thanks so much for the Wiki link. I updated the article with your info and link. Stay in touch.
Tim Layton Fine Art
Hello Peter, thanks so much for your comments. I am delighted to hear about your involvement with large format photography and thanks for catching the typos. You may want to try and find a Burke and James 8x10 because they tend to be very reasonable and they are great cameras. I have been using one for many years and I use it in my in-person workshops for students.
Pete Rearden(non-registered)
First, I think the autocorrect gremlin changed "midtone" to "midtown." Sorry, I'm a journalist. Copy editing is in my bones.

What interests me about LF photography is the way it has returned me to having a personal connection to every image. I spent years as a photojournalist, the true realm of digital photography. In that context shooting 2000-4000 images in a day is a great thing. Taking 2000-4000 images also robs you of your intimate connection to each image. It sucked the joy out of photography.

So I sold all my digital gear and picked up a FED2. Soon a 35mm rangefinder just wasn't enough. In short order I acquired a crown graphic, a CC-400, and a Toyo 45D. As a photographer they saved me. Now, the joy, no, the feeling of fulfillment is back. The sound of a Copal shutter brings a smile to my face every time I hear it. Staring through the loupe at a negative on the light table is pure satisfaction.

Now, I need to find an 8x10 camera I can afford.
I'm fairly certain Hurter and Driffeld were the instigators.

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