Each work is a pair. The left panel is a photograph as it was made. The right panel is the same photograph carrying one intervention derived from its own measurements. Side by side, the difference often lives at the threshold of vision, and it is stated exactly, down to fractions of a single tonal step. The numbers are the work, and anyone may measure them again. You are offered almost nothing to see, and everything to check. · · · The sky has been fitted to the CIE Standard Overcast Sky, the overcast distribution proposed in 1942 that daylighting still leans on and real skies only approximate. Moon and Spencer proposed the distribution in 1942 so that daylight could be computed without reference to any actual weather. The CIE later adopted it as the Standard Overcast Sky, and traditional daylight-factor calculations still lean on it. It sets sky luminance at (1 + 2·cos θ)/3 with zenith angle, making the zenith exactly three times the horizon. Across this frame's angular slice, 49.6° of vertical field with the horizon at the base of the far treeline, the standard requires a top-to-bottom ratio of 1.670. The photograph measured 1.356. With the field of view left free, this sky best fits a standard sky seen through a 22° window rather than a 50° one, and its RMS departure from the specification was 0.05001, against 0.05852 for assuming no gradient at all. As photographed, the sky sat closer to perfectly flat than to the sky the standard describes. How much of that flatness belongs to the weather and how much to the camera's tone curve, the file cannot say. The correction is multiplicative in linear light and confined to the sky and its feathered edge. The ratio now stands at 1.654 against the required 1.670. The RMS departure falls from 0.05001 to 0.00756, an 85% reduction. Maximum change is 15.5 levels and the mean is 2.844. The treeline's feathered boundary moves by at most a single level, and from row 420 down the land does not move at all. A real May morning over a road in rural New York, fitted to a document written for buildings. The two chairs are exactly as they were found. The only thing corrected is the part nobody was looking at. Presentation. The mount is RGB (231, 239, 243), the corrected sky's own top edge carried on past the frame. The fitted panel meets it with a step of 0.0 levels, and the untouched panel meets it at a step of 11, so the mount reads which panel the standard reached. There is no rule, since a line across the top edge would erase the one thing to look at. To check. The land, row 420 down, changes by exactly 0. The sky peaks at 15 of 255. Download this work's original file, 05_standard_overcast_sky.png, not a screenshot or a marketplace preview, attach it to an AI that can run code, and paste this: Run this exact line on the attached file, changing only the file path if needed. Show me its exact output, and say whether that output is exactly: peak 15 land 0 python3 -c "import numpy, PIL.Image as I; c=numpy.asarray(I.open('05_standard_overcast_sky.png').convert('RGB')).astype(int); a=c[690:2991,690:2991][::3,::3]; b=c[690:2991,3336:5637][::3,::3]; d=abs(b-a); print('peak', d.max(), 'land', d[420:].max())"