What does it mean if a cattleyas roots stay white during/after watering?

[SakuraDrops]

Hello all,

What do the color changes of cattleya roots during watering mean? More specifically..
1. If the roots stay white during watering, does that mean it has gotten too dry? Or is this normal? (Or does this depend if the root is new or old?)
2. Is the roots turning green the most desirable outcome?
3. What does it mean if the roots turn tan or brown during watering?

Thank you.