Wednesday, October 24, 2007

In the Throat

I have been deliberately slow to post any remarks about the fires we’re having around here this week. I’m fine. The fires are nowhere near me, but they’re all around me, from south to east to north. Their effect on the sky over me is hard to ignore.

But I’m not among the fires; I’m just surrounded by them. The nearest is probably fifty miles away. Except for what I see in the newspapers, I probably notice the effect of only one or two of the many fires all over the Southland. The rest are too far to touch my surroundings at all.

Thousands of people have lost their homes; hundreds of thousands—more than the total population of Long Beach or San Francisco—have had to leave their homes behind while fire crews fight the inferno. The net effect in my life has been to wipe up a tiny layer of ash from my kitchen drainboard.

But a couple of people by now have asked, just checking in to make sure I’m still breathing, I suppose. Yes, there has been a tiny whiff of wood smoke on the air lately. And the sunsets have been rich with color, if too hazy to burst with dramatic shapes.

“True” and “color” are a restless match. Our eyes are marvels, constantly adjusting to catch up with current lighting conditions, trying to represent the world around us in a way our brains can use. To us, a red beach ball looks about the same at night, by day, or under fluorescent lights. Sure, it’s not identical, but we recognize it each time. Cameras generally wallow along hopelessly behind our sophisticated system of visual perception. They usually start by trying to represent what a scene actually looked like.

Take a scene from a beach, a picture taken last Sunday. This is what the camera “saw”:

That’s already a little deceptive, because it’s actually how the camera interpreted the light that came through the lens, based on various settings I have adjusted. I let the camera decide how bright to make the picture overall, but I’ve got it set to skew the colors so they’ll be a tiny bit richer, and a little warmer. So it ingests the light, and then it applies a couple of adjustments before it ever records the scene. Then I get home and apply my fine tuning. Anyhow, what’s above is what came out of the camera, unadjusted.

“White balance” refers to an attempt to make sure that the various primary colors in a picture are equally well represented, ranging from absolute black to absolute white. It’s a dodgy business on a good day, but computers are getting better at guessing what’s right. Above is the same beach scene, using Photoshop’s automatic white balance adjustment. This actually overexaggerated the contrast from what I originally saw (trying to get an absolute black), and it made the shadows more blue than what I remembered.

This is the picture as I posted it on this blog on Sunday. I tried to preserve the relative balance of the tints (not skewing the shadows heavily toward blue), but I did enrich the colors a little, by both brightening the light spots and darkening the shadows. What did I really see, and what did the sand really look like? Those are both good questions. I was comparing what I saw on my (LCD) screen to what I remembered, not to the sand itself. And in the first place, I had never seen the sand itself. I saw the light from the sand through my polarized prescription sunglasses. That changes the color and also tends to boost the contrast (and clarity) of a scene.

Same scene, three different ideas of what it ought to look like. The Photoshop version is probably about what the sand would have looked like if the sky weren’t filled with dust: Photoshop took away the influence of the filtered light coming in through the sky making everything yellow-brown. In this case, that set of shades was the effect I was after, so I opted not to use Photoshop’s interpretation. That doesn’t make my picture accurate, except to say it more accurately shows what I wanted to show.

The New York Times Website has been running an interesting series of articles by Errol Morris lately about the tensions between photographs and truth, illuminated by (and illuminating) a set of photographs from the Crimean War. Morris’s photos are black and white. Color just adds another layer of confusion. Consider the following, and decide which is the true color:

In the veneer warehouse at work, we have green-tinted skylights. Plenty of light gets through, so you can see what you’re doing, but it’s all green. Most cameras represent scenes in the building with a green tint. When you’re walking around in the building, though, your eyes tend to adjust the green, automatically white-balancing everything, so you see an object’s colors fairly accurately, just as if you were in broad daylight.

Above on the left you see what the camera picked up with my usual default settings. On the right is the same scene, but with the camera set to adjust the white balance. I didn’t do anything fancy—I just let the camera make its own adjustment. But now take a look at what the home computer does:

Here I have used Photoshop to automatically white-balance each of the original shots, using its algorithms. See how much warmer the original shot comes out? That’s probably the way you’d want the wood to look in a final reproduction. Compared to this, the camera’s automatic white balance has rebalanced the shot to avoid green, but in the process it has ended up looking washed out. Part of this is a matter of taste. With wood, it’s actually important to give a customer a realistic representation of what the end product will look like—shade, grain, contrast. (Not all wood is the same shade of brown.)

It never surprises me when a full-blown computer with all the time in the world does a better job of enhancing a photo than a digital camera can do on the fly under adverse conditions.

So I could post more pictures of what the sky looked like today, but I’m naturally reluctant to give the wrong impression, whether it came from the camera itself or from postproduction.

As Laurie Anderson pointed out, “It’s a sky-blue sky.” Even when the heavens are choked with smoke, they are definitively sky-blue. Or sky-yellow. Whatever that sky color is called.

From a somewhat different perspective, the shots below are from the excellent NASA Rapidfire site, which quickly posts satellite shots a matter of hours after they’re taken. In the top shot, I have added two green spots. The lower spot is where I live, and the upper spot shows where I work.

Monday October 22, 11 a.m. Pacific time. Along with the white plumes of smoke, notice above the large brown plume of dust blowing out to sea. On Sunday I remarked at how much grit was in the air. This shows the same happening Monday morning. Winds remained high.

Tuesday October 23, 8:25 a.m.

Tuesday October 23, 11:40 a.m.

Wednesday October 24, 9:10 a.m.

Wednesday October 24, 10:45 a.m.

Even with all that smoke looking as if it was choking the area, I didn’t get enough ash falling on my windowsills today to make it worth posting a picture of it. And outside this evening I didn’t especially taste wood smoke in the air, as I have (slightly) for the past couple of days.

The winds have shifted; no longer are strong winds from the east pushing streamers of smoke tens of miles out to sea. Last night the air felt damp for the first time since the weekend, a good sign. This morning and tonight, the wind was blowing from the west again, a welcome harbinger of cooler air for all of us in fire country.

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