There's been a lot of controversy about the mars pictures, about the filtering NASA is doing to match the color balance to the colors of the red planet. I think NASA is doing their best to get the result technically correct... but that best just isn't enough

A Failure of Vision

I'm not going to argue here that NASA is hiding something, or that Mars isn't red, or anything silly like that... but I think NASA is making a mistake in the color balancing they're doing. It's not really a technical mistake... I'm sure they're doing their best to balance the pictures to match the pictures something like a good film camera would produce if it was there.

The problem is, the human eye isn't a camera, and the human eye adjusts to the environment. That's why photographers use filters, to try and get their accurate camera to produce the image they see... not the image that their good film camera would make.

I look at my hand in the sun and in shadow, in the morning and evening, under incandescent and fluorescent light, and it looks like "the same" color, even though it's often radically different. I adjust the color temperature on my monitor from one extreme of its range to another and in less than a minute the "white" looks white again. Because the pattern recognition going on in the brain is tuned to that filtered input, and things under strange lights "look funny" until you adjust to it.

So if you were standing on Mars, you'd adjust. The red light filtering through the dust in the air would be filtered out by your brain, you'd adjust to a world with a red filter on it. You'd come back from your Martian vacation with a bunch of snapshots that look funny, perhaps, or maybe there'd be an automatic "Martian Light" filter in Photoshop 2100 to fix them up for you.

So I've been playing with the Martian pictures, and usually there's an obvious level adjustment in Photoshop that undoes NASA's work. Little peaks near the high end that you can line up, and get back to the raw levels.

Usually, that's enough. Looking at the uncorrected image the details of the surface jump into focus, the patterns of red and pink make sense as black and red, and you can easily make out craters that were vague blurs, the way the wind undercuts rocks and leaves trails in the dust is suddenly just obvious.

And that's the real problem. Unless you're sitting in a dark room running picture after picture across the screen, looking at Red Mars with Mars-adapted eyes, it's hard to see what the scientists at NASA are seeing. Out here in the rest of the world, our Earth-adapted eyes just get more out of the pictures that haven't been finetuned to standard Mars light. It's not a technical problem, it's a people problem. You might call it a failure of vision.

 IO
Lynx-enhanced by <peter at taronga.com> (Peter da Silva)