Not the answer I expected. I figured it was her wearing white colors to make her signing easier for you to pick up (no idea the extent of your vision loss). My wife does ASL interp for D-B as a volunteer, and she has loads of black clothing for this purpose. For some, she has to sign into their palms.
What a sad group of people that hurl insults at you and your wife.
Oh, I was talking about in the context of being the target of racism and ableism. As for signing, she signs into my palm. I can see some colors up close but I can't see well enough to understand signing visually, even with high contrast.