One thing I try to take into account when I’m writing a talk is how the talk will work for people who cannot see well or at all. It’s easy, when you have good vision, to simply assume that everyone else does, too. But there are lots of ways that assumption falls over—everything from protanopia (the most common form of color-blindness) to total blindness.
There’s a question here that you must keep in mind when it comes to slides: Is my talk comprehensible without the slides? Because the reality is that some people simply cannot see them. At all.
Here’s a helpful way of thinking about it: however you actually go about building and rehearsing your talk, think about its content like a podcast episode. If someone can’t rip the audio out of the video stream, upload it to their podcast player, and follow along without any issue whatsoever… you’re leaning too hard on your slides.
I was reminded of this quite sharply by two things in the last week:
I did rip the audio from a couple talks and upload it to my podcast player and listen to them while walking and running.
I gave a talk at a meetup that involved some live-demoing/coding and I was thinking afterward: had anyone in the room been hard of sight or unsighted, they could not have followed much of what I said at all. No one was (to my knowledge!) but it had me thinking about how I would solve for that were it otherwise.
So: think hard about making sure people in the audience who can’t see your slides can still follow your talk.