Using Very OLD RODINAL ---

Last ORWO NP20 I did in RODINAL 1+50 was under-developed . The Rodinal was now a ' Dark Brown Colour' with Crystals at the bottom -- so I gave it a 'test' -- I microwaved it gently at 50% for 45 secs several times, trying to break up the Crystals as I did so . It got quite 'Warm' ! I cut the short test length of ORWO NP20 rated 50 ASA in my Chinon CG-5 and processed in RODINAL 1+25 for a 'Guessed' 10 mins @ 20oC and got GREAT NEGS !! I could have rated the outdated film faster at 64 ASA even . I will use up the rest of the 'Brown Microwaved RODINAL' now ! THIS one was using my SMC Pentax-A 24mm f2.8 to see if I could 'Hand-hold' it in dreadful light at f4 -- I think I managed it -- got 1/15th second.

Old Rodinal Test 01 by Peter Elgar, on Flickr
This one was a Test on my VIVITAR ( Made by KOMINE) 135mm f2.8 at full aperture f2.8 in dull light

Old Rodinal Test 02 by Peter Elgar, on Flickr
!+25 seems to give better results on the Dark Brown Rodinal than 1+50

How old was the "very old Rodinal"? Do you have any hints to its age?

IIRC, there was a thread on Parodinal, mixed with Pharmacy Grade Acetaminophen (or the active chemical in it), which was very clear and stayed clear, and usable for some time afterwards.

It was mixed by a member in the Philippines, who had a hard time getting many chemicals from the U.S...

I believe Donald Quails was very caught up on this topic, so I suggest you look at his posts for leads on longevity.

IMO.

When Agfa announced end of Rodinal production I bought enough to last several decades. Still have quite a few bottle of Agfa Rodinal. Amazingly, I can detect no change in development qualities and have never experienced any crystallization. Maybe I’m just lucky. Keeping potential for Rodinal is unbelievable.