The first thing you need to know is that there are 3 "states" in a trichomes development.
The first state is clear. Clear trichomes contain precursor cannabinoids (cannabinoids are the different substances in cannabis).
These precursor cannabinoids are not psychoactive (they do not produce a 'high') yet and harvesting clear trichomes will not give you a proper harvest.
The second state is cloudy/milky. Cloudy trichomes contain fully realized THC (the by far main contributing substance in any cannabis high).
You want to get as close to 100% cloudy trichomes @ harvest to get the most potency out of your plant. It's impossible to get 100% cloudy trichomes, since trichomes are always being produced and are always maturing, even after harvest the trichomes will continue to develop.
The third state is amber. Amber trichomes contain degraded THC --> CBN. CBN represents a loss of 90% potency (from THC).
CBN is not desirable in any harvest, since it not only represents a huge loss of potency but research into the substance has also shown that CBN does not produce a high like THC does, CBN produces a more sickly feeling not a true high.
Understanding the difference between clear - cloudy - amber trichomes is essential in getting a proper harvest with a peak potency.
