Try phenolphthalein?

What's phenolphthalein?

It's phenolphthalein. It won't affect the copper.

Phenolphthalein test indicates it is blood.

- Bad phenolphthalein? - I hope not. It's the only we've got.

Wick. I used phenolphthalein and hydrogen peroxide in anok's open chest cavity.

- Black's not even on the chart. - Bad phenolphthalein? - I hope not.

- Agent Booth and I are gonna swab each ofyour bells... with a cotton ball soaked in phenolphthaleine.

Oh, the walls are dripping blood... ...which looks nothing like a phenolphthalein indicator... ...exposed to a sodium carbonate solution.