The 20-mL amount was chosen to
be the same volume used in the other sample preparations,
and the 60 mL amount was used because it had been
shown to result in a clear, bright color change. There were
2 controls: 20 mL of methanol and 20 mL of water, which
resulted in a total of 10 different papers. The papers were
presented to the subjects on one tray in random order.