The one on the right is Congo Red Powder C.I. 22120 dissolved in water and filtered (I asked my friend who gave it to me) and remains red in KOH. Actually, when searching for my stuff, I just realised that I have bought a bottle and forgot about it - so at least this post was very beneficial !!! The one on the left was bought a few months ago from a commercial Lab Supplies and they provided it as a solution (1%). Well, I can make my own Congo Red solution from 22120... I guess 1% is a good concentration or a bit less is better? Since my Lab is home-based I prefer to avoid Ammonia.
P.s. Does it really expires 🤷♀️😁 ?
