Vilken potion behöver du utveckla bilder?

Jag tror inte att Rowling någonsin gav det potionet ett namn. Faktum är att citatet du gav ovan var det enda som nämnts i serien.

Här är lite som JK Rowling hade att säga om det (ursprungligen publicerat på hennes hemsida, reposted på MuggleNet.com-forum ):

JKRowling's website, F.A.Q.
As a vast number of people have pointed out to me in the last twenty four hours (some of them related to me by ties of blood) Colin DID develop a photograph from his camera in 'Chamber of Secrets' (my previous answer stated that he never did so).

Cameras, like radios (or, as the wizards call them 'wirelesses' – they're always a bit behind the times when it comes to Muggle technology) do exist in the wizarding world (there's a radio in the Weasleys' kitchen and we know there are cameras because of the moving photographs you see everywhere). Wizards do not need electricity to make these things work; they function by magic, but in the case of such objects the wizards liked the Muggle invention enough to appropriate the idea without adding cumbersome plugs/batteries.

I have an old notebook in which it says dev sol (potion) magic [indecipherable word] photos move. Adept as I am at interpreting my old scribbles, I can tell you that the original idea was that wizards would use a magical developing potion to make their photographs move.

SO... as Colin's batteries can't work in Hogwarts, clearly his camera is running off the magical atmosphere and he is then developing his photographs in the magical potion that causes the figures therein to move. All of which goes to show that Colin has a lot more initiative than I ever realised.

dev sol verkar vara stenografi för att utveckla lösningen.