
thumb|RODINAL Rodinal is the trade name of a black and white developing agent produced originally by the German company Agfa based on the chemical 4-aminophenol. Rodinal is a popular high acutance black and white developer and is used at different dilutions for development in rotary machines, by agitation, as well as for stand development.
thumb|RODINAL Rodinal is the trade name of a black and white developing agent produced originally by the German company Agfa based on the chemical 4-aminophenol. Rodinal is a popular high acutance black and white developer and is used at different dilutions for development in rotary machines, by agitation, as well as for stand development.
== History == Rodinal was patented on 27 January 1891, making it the oldest film developer which is still commercially available. Novel at the time of its invention was that it is delivered as a liquid concentrate that had to be diluted and not as a powder. By changing the dilution the development speed can be greatly changed.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).