No it's not done. I didn't even bother looking at the zoomed trichome photo because I can tell just by looking at the plant. If you get too focused on trichomes you'll most likely harvest early. I don't even look at them anymore and haven't for years.
Despite what some people or chart says trichomes are not the best determination of when to harvest. All kinds of things can make the trichomes change color and then there are plants where they won't change. Harvesting by trichomes has led many people to consistently harvest their weed early and miss out on the full effect of a finished plant.