The next step—the eighth—crosses a boundary: I venture out at twilight, and catch my first glimpse of a non-dark world, painted in subtle shades of grey.
Equipment is required in order to progress to the ninth thing. The human eye, because it is so instantly responsive to conditions, is very bad at judging absolute levels of light. I would like to venture forth a little earlier, to catch some colour in the world, before it drains away. But how to judge, in different seasons and under different skies, the amount of light to which I’ll be exposed?
Once more I have reason to be grateful for Pete’s photographic bent. “What you need is a light meter,” he says, and procures me one from a technical website. It is a rectangular black palm-sized gadget, with a white half-sphere at one end to measure ambient light and a digital display on which the reading appears.
Pete sets it up in idiot mode, so that, unless I really put my mind to it, I cannot mess things up—and a whole new world of objective measurement opens its doors. “This evening I did f2.8 at one second,” I say happily, having been in the garden a little after sunset, but before the world is monochrome. It is early June—I have looked at orange poppies and pink roses, and watered tomato plants like green and writhing snakes. The colours slam into my retinas like crossbow bolts—but it is sweet pain.
I learn the peculiar scale that light meters employ: f1 (almost dark) is followed by f1.4, f2, f2.8 then f4 (about when street lights come on), f5.6, f8 (the sun just above the horizon, if the sky is clear). Pete explains that each step up represents a doubling of the amount of light, so I should be prudent when attempting to move from one level to the next. He also, lest I get too excited, points out that light levels at noon are f200 plus; I am taking baby steps, nibbling at the edges of the day.
Nevertheless, I am thrilled to have a way to track my progress. I note down in my diary each evening the f-number at which I went out. When people ask me how I am, I reply at first with incomprehensible technical blather, describing how I “managed f8 yesterday and hope to try f16 at the weekend.” Only photographers understand.
My diary has a useful page showing sunrise and sunset times for each week of the year. This is very helpful for me, as I can work out at around what time I should start preparing for my walk. I have become a dusk-tracker, an adherent of planetary rather than human time, following the swing of the earth as it loops around its star. My slice of dusk moves through the day, its contents changing with the seasons as the days contract and dilate like the slow pupil of an eye. In winter I coincide with children in scarves and hats walking home from school; at equinoxes, with the return of car-borne commuters to suburban driveways; in April and August, with the hour of soap, when there are few people abroad and giant TV screens effloresce from the walls or corners of front rooms. Around midsummer I must wait and wait for hours, far into the evening, as a fiery teardrop slides down the blue cheek of the sky.