A bottle sits on the film developing worktop. A treacle-brown liquid meets an equal quantity of air in the container, and, as film developers go, it looks to be in a sorry state. Air = oxidation = spent developer, right? In film developing terms this bottle is however half-full, not half empty.
(Please excuse the terrible pun.)
I don't know precisely how old this bottle is. It seems to have escaped my usual practice of labelling with an opening date in marker pen (definitely recommended). Looking at my negative collection, I estimate it was opened in 2013.
R09 - a modern day copy of the famous Rodinal - is liked by many photographers for its tonality. I haven't developed very much with it in comparison to other developers, so I won't make a judgement on this. You will notice the grain in your image with this developer (especially with medium speed and fast films).
It was always purported to have a splendid shelf-life, but today I confirmed that for myself. I present below the latest addition to my Pebble Project, FP4+, developed in the formula in question. I was very pleasantly surprised to see a half-opened bottle of some age produce a perfectly good looking negative. A fresher batch may produce better results (the label on the bottle recommends not exceeding six months when opened).
It looks like I have found a good developer to keep at the back of the cupboard for emergencies.
FP4+ R09 (Rodinal) 1+50 15mins 20c
To access the full gallery so far, go to Resources on the main menu above and select Pebble Project Galleries.