His practical experiments yielded only shadow image photograms that were not light-fast, but his conceptual breakthrough and partial success have led some historians to call him "the first photographer".

His biographer notes that "neither his extant letters nor family tradition tell us of his caring for any woman outside the circle of his relations" and that he was "strongly attracted" to musical and sensitive young men.

In a letter that has been variously dated to 1790, 1791 and 1799, Watt wrote to Josiah Wedgwood: Dear Sir, I thank you for your instructions as to the Silver Pictures, about which, when at home, I will make some experiments...In his many experiments, possibly with advice on chemistry from his tutor Alexander Chisholm and members of the Lunar Society, Wedgwood used paper and white leather coated with silver nitrate.

David Brewster, later a close friend of photography pioneer Henry Fox Talbot, published an account of the paper in the Edinburgh Magazine (Dec 1802).

The result being that it would immediately act upon any gelatine present to render it insoluble; hence its use, since time immemorial, to tan leather which is a strategic material (i.e., for solder's boots, and harness to attach guns to gun-carriages etc.).

[7] Reade's images darkened quickly because the tannic acid component of the"extract of galls" has the power to spontaneously reduce silver nitrate to its metallic state.

It may indeed be examined in the shade, but in this case the exposure should be only for a few minutes; by the light of candles and lamps, as commonly employed, it is not sensibly affected.Although unfixed, photographs such as Wedgwood made can be preserved indefinitely by storing them in total darkness and protecting them from the harmful effects of prolonged open exposure to the air—for example, by keeping them tightly pressed between the pages of a larger book.

In the mid-to-late-1830s, both Henry Fox Talbot and Louis Daguerre found ways of chemically stabilising the images their processes produced, making them relatively insensitive to additional exposure to light.

In 1839, John Herschel pointed out his earlier published discovery that hyposulphite of soda (now known as sodium thiosulfate but still nicknamed "hypo") dissolved silver halides.

His was only one of several latter 19th century claims alleging the current or former existence of improbably early photographs, usually based on decades-old memories or depending on questionable assumptions, which investigators determined to be unverifiable, unreliable or definitely mistaken.

[9] An authentic Wedgwood image would be a key historical relic, avidly sought by collectors and museums, and would probably sell for a seven-figure price at auction.

[10] If any special physical analysis was later done, the findings had not been made public as of mid-2015, when Schaaf presented some new discoveries which apparently solved the major mysteries and laid his unexpectedly sensationalised scholarly speculation to rest.

The initial "W", it now seems, is that of William West, an entrepreneur who was selling packets of "photogenic drawing paper" to the public only weeks after instructions for its preparation were unveiled by its inventor, Talbot, early in 1839.