At some point in your journey of capturing videos for lecture, you'll want to know about BALANCING LIGHT/COLOR (generally) and WHITE BALANCE (specifically). Here's a visual — top left image, captured at night; bottom left image, capture during day:
Easy definition for balancing light/color?
Adjusting complementary colors relative to a reference point. That reference point can be a white sheet of paper (like the kind from Delta's Printshop), middle grey (a.k.a. grey card), color bars (think broadcast TV), or a color chart.
While the physics behind balancing is the same regardless of equipment, the interface can vary. Typically, you want to look for TEMPERATURE and TINT. If your equipment has a WHITE BALANCE MENU but uses other terminology (e.g., on an Elmo, you might see R-Gain and B-Gain), it should be pretty easy to determine which is TEMP and which is TINT.
For video, you want to balance BEFORE capture. For still images, you can balance after but rule-of-thumb (especially if you're working on high-stakes material)? Balance as much as you can BEFORE; make micro-adjustments after.
Remember: post-production (after capture) software can only work with available information in an image file. If information is not there or your capture is highly compressed, then you might never be able to achieve perfect balance after capture! That's why in the example above (top right), the result still has a yellowish cast.
Now, I must be 100% honest:
I've balanced complementary colors a gazillion times, and every time? I still need to write down the complements so my brain does not get confused. So, here's a cheatsheet with explanations below the image:
STEP ONE (see top right on cheat sheet):
When I balance manually, I use my reference point (e.g., blank sheet of white paper), to first adjust the TEMPERATURE OF LIGHT. If my image looks too yellow (or orange)? I move towards blue; if my image looks too blue? I move towards yellow. I do this until either blue or yellow, respectively, is mostly neutralized relative to my reference point.
STEP TWO (see bottom left on cheat sheet):
After I balance for TEMP, I do a (micro) adjustment for TINT. Again SLOWLY adjust towards either magenta or green to get your capture as close to your reference point as possible.
And that's it. Balancing really is that easy!
Let me know if questions.