Hi Max, found it in HK, your old stomping ground (city super @ causeway bay), unfortunately its not available in singapore. The washing soda that I bought seems to be slightly hydrated from the humidity in asia causing inconsistent results, so if you get some, make sure you bake them a bit, not too long and hot, just enough to dessicate the crystals.
The batch that I posted was straight kopi-o (no vitamin C) the second batch which was a dismal failure due to a bad batch of lucky 100 film had vitamin C and much shorter times, was much cleaner. Unfortunately, no usable negatives from that batch, but sharp, stretched mid toned images through the bad emulsion though. Anyways I will post up that batch later, splotches and all for you to have a look
Vitamin C powder was another adventure to find, but eventually found it at Holland and Barrett in Vivocity (super expensive for small bottle), you can use 2 redoxon tablets as well to substitute the powder.
It was out of the blue I decided to experiment with Caffenol, I had wanted to lace my Rodinal with Vitamin C and somehow the ingredients fell in place for me to try caffenol instead....and since i had pyro on hand, i wanted to see how it stacked up against an almost 100 year old recipe
I'll be messing about with Caffenol C-H this weekend again when I have more time to shoot and refine process and times....will post results as always
Expensive experiment 8 cups of coffee for 1 roll, easier to use pyro