Raining Stair-rods

I have just read your thoughts on the phrase 'Raining Stair-rods'. I seem to remember that this phras was coined in the early days of photography when the aperture shutter speeds were very slow.

When a photographer took a photograph in the rain, the rain was recorded on the film plate as a long thin bar, similar in appearance to a stair rod.

The ruined photograph was then said to be ruined "Because it was raining stair rods".

Quite logical. It is also true that, our vision being what it is, the "stair-rods" sometimes appear on our retinas as well. Why consider the photographs to be ruined? The "stair-rods" graphically illustrate what the photographer was trying to create--the impression of a heavy rain. Long exposures often show an aspect of the truth not revealed by a short one.
BB

In case there's any doubt as to what Jeff Watson means by "your thoughts," here's a link to "our thoughts," as found in, e.g., the Archive.

www.phrases.org.uk meanings 298200.html