The singular correct trichome color for when to harvest is whatever trichome color best fine tunes your harvest the most/best that you can, of course within genetic limits, making it as good for you and for you alone as you possibly can.
People preach specific trichome colors and tell others that is the very best time for the person to harvest. Well all that was actually told was what the other person liked the most for the strain types they grow, and nothing more. It was pure personal opinion that normally will be limited to some certain general range/grouping of strains.
To one person trichomes that are mostly clear and just a few have become slightly milky means perfection. To someone else dark amber is the bees knees. The things that make something right or wrong are partially personal preference and the rest is due to differing plant genetics.
Just because of differing plant genetics alone any color chart or advice has to be taken with a grain of salt regardless of how spot on it might seem at times. THC levels peak sooner than most believe them to, or that most charts claim. The thing is that at that time much THC is not fully psychoactive, even later it is not all psychoactive but there is less earlier even there is more actual THC overall. Rather than allowing the THC to turn psychoactive while drying and curing many grow longer to basically ripen on the vine. But when that happens you lose THC.
Once trichome color begins to change THC is oxidizing and breaking down into CBN. While most strains will begin with a clear trichome color it is not impossible that they can begin slightly yellow or slightly amber. It is not so much the individual first or original color but when it begins to change, to cloud, to darken that THC is oxidizing.
Genetics will always make a difference, that is if the difference is great enough. A pure sativa has the highest percentage of THC it will have just before the first bit of clouding begins. To many that would be seen as being far too early to ever considering harvesting. But it would be prime time for a true connoisseur of sativas. Of course the more or less equal opposite could at times be the case. A pure or almost pure sativa will just hit its maximum THC level sooner than other strains that have some amount of indica, more making for a slightly more significant difference. But some people tend to believe there is an across the board right or wrong, good or bad, perfect for all situations and genetics moment to be told to others and the precise moment to harvest.
They are full of manure.
What all that means is each individual has to learn what general type of genetics they prefer and what each genetic grouping/makeup chosen should give them, which should be targeted to give the person the very most of what they hope to end up with.
As in if someone enjoys to get stoned instead of high and likes what is called by many ‘couch-lock’ effects but still have maximum levels of THC to purchase genetics that are high in THC levels and high in CBD levels and harvest slightly earlier than they might think they should. The higher percentages of CBD will give them part of what they want and the increased levels of THC will boost overall performance.
That makes more sense than someone purchasing something that is as high in THC as they can find but that might be low in CBD, ‘couch-lock,’ and trying to make up for it by allowing plants to grow to long resulting in increased amounts of THC lost to oxidation turning into CBN, that causes a ‘messed up and I don’t want to move’ feeling that is confused by many as potency and ‘couch-lock’ and believed to be ‘better.’ At least it always made far more sense to me. Why willingly trade off some of the most coveted of all cannabinoids, THC, increasing CBN that is only being sought for because someone did not pick genetics that were high enough in CBD to begin with because they had to have the flavor of the month strain and then attempt to bend it into giving something other than what it was really genetically meant to offer?
Once someone actually figures out strains and effects of cannabinoid in differing proportions, then they need to learn how to tickle out of it that little bit extra that makes it the very best for them, and for them alone harvest, and then do things that way regardless of how many people wrongly claim them to be doing things incorrectly.
We attempt to create something we love as best we can, but at times there are two ways to get to what seems to be pretty much the same place. But the similarity is really only superficial and regardless of perceived similarities one route is most definitely an injudicious option to pick. Sadly far to many pick that injudicious option on a regular basis.