Hey all,

My question is about the spectrophotometer.

I am trying to read the % T of E.coli in MaCckonkey broth which has the color violet to Blue. I am asking at what wavelength should I be reading my sample? is it at the Yellow- Orange wavelength or the Blue-Violet?

One more thing should I blank every time I use a different concentrated sample? (my blank in this case is the MaCckonkey broth media only).

Thank you guys.