When was this photograph actually taken SHADOW
Metadata is stripped by every app it passes through and trivially edited where it survives. The sun is neither.
Where and when it is said to be
The clock offset is the single commonest way one of these calculations goes an hour out. A picture taken in London in July is +60, not 0, because the clock was on summer time. Neither the place nor the date leaves this device.
The shadow you measured
Height and shadow can be in any units at all as long as both are in the same one: only the ratio matters, which is why a shadow can be measured off a photograph with no scale in it. Leave the direction blank if you cannot tell which way north is; the answer is then wider, and honestly so.
When it could have been
The curve is how high the sun stood through the day. The shaded bands are the spans your measurement is consistent with: there are usually two, one as the sun climbed and one as it fell, and the direction the shadow points is what tells them apart. The dashed line is the time claimed.
Against the claim
How it works
Photo metadata is stripped or easily edited, but the sun is not. SHADOW estimates when a photograph was taken, or checks a claimed time, from the direction and length of a shadow and the place it was taken. It compares the shadow with where the sun would have been. It gives a range, not an exact time. The photo stays in your browser.
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