Trichome Development.

I'd take m0use's answer here... makes the most sense!

Anthocyanin is the name of the pigment purple. Chlorophyll is the green pigment. It is not that the chlorophyll is green, it absorbs all other colors and reflects only green. With genetic conditions existing using higher concentrations of UV/blues plants can opt to switch the pigments within its leaves to purple in order to utilize more efficient use of available light. Very common in strains such as grand daddy purple. Anthocyanin has a long slue of therapeutic properties. Packed full of iodine. Very very good anti radiation properties. That's why they post them through your door if you live close to a nuclear plant.

It's totally normal. Just the anthocyanins. Anthocyanins are water-soluble flavonoids which contain coloring pigment usually found in the epidermal layer of plants. They can travel up the trichromes and color them.

The red colour that you see is a red/purple colour and this is 100% normal with a Indica strain like Northern Lights. This is cause by genetics and you will see a lot of Indica dominant strains develop red/purple colours in the buds. This has actually nothing to do with the trichomes. Here is a link with everything you do need to know about trichomes. https://dutch-passion.com/en/blog/what-are-cannabis-trichomes-and-how-do-they-affect-your-smoke-n986

My dear grower mate...the redness that you see within the trichomes and some times boarding the resin cells are normally to kinds of compounds...cyanophite compounds that normally tend to be more purple or dark reddish or in the case of the Northern Lights strain some carotenoids and beta-carotenoids (that goes from reddish to dark orange tones). Normally they are metabolic sugar formation processes that form along the maturation of the trichome resins and it is a sign that your growth is integrating in almost optimal way the sugar tricyclic metabolites formed by the coloides within the root system. Keep doing that amazing job of "feeding" properly your flowering stage and this kind of reddish liquid within the trichomes is mostly like to occur on some genetics and precisely the "genealogy" of the Northern Lights strain is very propense to this kind of carotenoids reveal itself.