I have an open bottle of R09 developer and it has crystals at the bottom of the bottle. Is it an indication that it has gone bad?
Check the color of the fluid in the bottle. If it's dark or black, discard. If clear (amber OK) place the bottle of concentrate in a bowl of hot water from the kitchen sink. As the temperature elevates, shake periodically, as this will speed the re-dissolving of the crystals. Worried it's bad? Cut off a snip of the tongue for testing. Make a tiny volume of developer at approximately working strength and swish this test film in it. This is done in room light. If the sniping turns black, you are OK.
R09 - or Agfa Rodinal - is a developer known for longevity. I have friends who use East German R09 (30 years or so old bottles) with great success.
But it is long lived in more than one sense - it has been around for ever (since 1890'ies) and the patents that once covered it have long lapsed. Over the years there were several variants produced - some still are - and they do not keep the same. For example the Czech Foma R09 is rumored not to keep as well as the German stuff (it is rather cheap though, and works exactly the same when fresh).
A rattle of crystals in your bottle of stock developer is usually not a problem with Rodinal, but you should:
- make sure that the crystals do not make it into your developing tank (they could lead to "peppering" of black spots on your negative).
- make a test before any critical work; sudden death syndrome (developer good one day; gone the other) can occur.
But crystals in bottle of Rodinal do not necessarily mean dead developer.