I am Lester Cook. I am 58 years old, and I have taught black-and-white photography at a public high school in Fresno, California, since the fall of 1969. In thirty years I have watched a great many teenagers see their first print come up in the developer tray. Their faces at that moment are the reason I have kept the job. My own work is done with a 4x5 view camera, a wooden field camera that folds into a box the size of a dictionary, on a tripod that weighs more than it does.

Every one of my students hears about Ansel Adams, usually in the first week. This page is the version of that lecture I give to people who did not sign up for my class. It contains no pictures of the man and no copies of his photographs. Those belong to his estate, and in any case a photograph of a photograph on a computer screen is not the photograph. Go to a museum and stand in front of a real print. Then you will know what I am talking about.

I will describe them. You will have to find them yourself, in a library book or, better, on a museum wall.

Monolith, the Face of Half Dome (1927)
The great flat face of Half Dome, seen from a ledge on its own shoulder, with the sky gone nearly black. He had hauled heavy glass plates up the mountain and had only a couple left. He realized that a straight exposure would show the rock as he saw it, but not as he felt it, so he put a deep red filter on the lens to darken the sky. He later called this the first time he truly saw the finished print in his mind before he made the exposure. I first saw it in a book in a college library in 1961, and I can still tell you which table I was sitting at.

Moonrise, Hernandez, New Mexico (1941)
A small village at dusk, a church, and in front of it a little cemetery whose white crosses are catching the very last of the sun. Above them, a huge dark sky, a band of cloud, and the moon. Adams saw it from the highway, pulled over and ran for his camera. He could not find his exposure meter. He knew the brightness of the moon, though, 250 candles per square foot, and placed it on Zone VII and worked the exposure out in his head: about one second at f/32. He made one sheet. When he turned the holder to make a second, the light had left the crosses. One sheet. I tell my students this story every year, and every year at least one of them understands that knowing your craft cold is what lets you act quickly when it counts.

Winter Sunrise, the Sierra Nevada from Lone Pine (1944)
The east face of the Sierra, white with snow and lit by the first sun, standing over dark hills still in shadow, and in the middle, very small, a horse in a sunlit pasture. You could look at it a long time before you noticed the horse, and then you cannot stop seeing it. A note for teachers: the students at the local high school had put their town's initials in big white letters on one of those dark hills, and Adams went to a good deal of trouble to spot the letters out of his prints. I have some sympathy for both parties.

Clearing Winter Storm, Yosemite National Park
The Valley from the west end, El Capitan on the left, Bridalveil Fall on the right, Half Dome far off in the middle, and a storm breaking up and pouring out of it all at once, cloud and light and fresh snow on every tree. If you have stood at the Tunnel View pullout on Highway 41, you know the spot. If you have stood there in a winter storm, you know how rarely it looks like that.

Yosemite Valley is about seven miles long and a mile wide, with granite walls rising three thousand feet and more on both sides. For a photographer this means two things. First, the subjects are enormous and they hold still. Second, the light is never simple. The sun comes over one wall late and goes behind the other early, and in between it is always lighting one thing while another stands in deep shade. The range from the darkest shadow to the brightest granite in the Valley at noon is far more than film can hold. That is precisely the problem the Zone System was built to solve. I do not think it is an accident that he worked it out after more than twenty years of photographing this place.

It is about two hours from my front door in Fresno to the Tunnel View, up Highway 41 through Oakhurst and Wawona. I have made that drive more times than I can count, and I have never once come out of the tunnel without catching my breath.

Start here. Your light meter is a simple-minded instrument. Point it at anything, a coal pile or a snowbank, and it will tell you how to make that thing middle gray. It does not know a coal pile from a snowbank. It assumes the whole world is middle gray. The Zone System is simply a way of telling the meter where you want things to go instead.

The scale. Adams divided the tones of a print into eleven zones, from pure black to pure white, numbered in Roman numerals from 0 to X. Each zone is one stop from its neighbor: one stop means twice the light, or half. Zone V is the middle gray your meter is always aiming for.

Step one: the shadows. Meter the darkest part of the scene in which you still want to see detail. The meter will give you an exposure that would make it Zone V, middle gray, which is far too light for a shadow. So you place it on Zone III by giving two stops less exposure than the meter says. Now your shadows will be dark, and they will have detail. Exposure is what decides the shadows. Once the shutter closes, nothing you do later will put detail into a shadow you starved.

Step two: the highlights. Now meter the brightest thing in which you want texture, and see where it falls on the scale once the shadows are placed. If it falls on Zone VIII, you are in luck: develop the film normally. We write that as N. If it falls on Zone IX, it will print as white without texture, so you develop the film for less time, which holds the highlights down by a zone. That is N-1. If it falls on Zone VII, the scene is flat, and you develop longer to push the highlights up. That is N+1. The shadows barely move either way. How much time is a zone? That depends on your film, your developer and your water, and you have to test it yourself. That testing is most of what my students do in October.

The short version, the old darkroom rule every photographer learns sooner or later: expose for the shadows, develop for the highlights. That is it. Adams spent the rest of his life refining those six words into three thick books, The Camera, The Negative and The Print, and I recommend all three, in that order.

And this is why he worked in sheet film. With a 4x5, every sheet is its own negative and can be developed on its own, N for one sheet and N-1 for the next. With a roll of thirty-six exposures you have to pick one development for all of them.

They arrive knowing him from calendars and posters. Every dentist's waiting room in the San Joaquin Valley has an Ansel Adams calendar, and half of my seniors have Moonrise on a dorm room poster by the following Christmas. They think of him as wallpaper. Then they make their own first negative, and it comes out gray and muddy, and they make a print of it, and it comes out grayer and muddier, and they hold it up next to a reproduction of Clearing Winter Storm and they go quiet. That is when I hand them the spot meter.

Some of them find him old-fashioned. Mountains and trees, no people, no cities, nothing ugly, nothing wrong. I tell them that is a fair criticism, that Adams himself photographed people and cities more than they know, and that they are free to go photograph whatever they like as long as the shadows have detail. A few of them go out and make pictures of parking lots and laundromats and their grandmothers' kitchens, beautifully exposed. Those are the ones who understood him best.

Every spring, when the dogwoods bloom, I take a van of volunteers up to the Valley for one day. Most of them have never been, though it is two hours away. I have watched a seventeen-year-old who had never left Fresno County step out at Tunnel View and simply sit down on the wall. That is the whole lesson, really. Everything else is technique.