Photograph of positive electrical discharge. Captured by Alan Archibald Swinton around 1892.
In the late 1880s, French astronomer Étienne Léopold Trouvelot captured the first photographic images of electric sparks, called Trouvelot figures.
British electrical engineer and amateur photographer Alan Archibald Campbell Swinton produced his own beautiful examples. He captured both a negative and a positive electrical discharge on glass plate negatives.