According to this interview, Ross Jr. said:
"There, we had the old original negatives of those shows that my dad did. Over the last few years, we've been going through each of the episodes and returning them to that glory, that actually, probably has never been seen, because as you know, back in the 60's, most people didn't have color television. So most people thought the shows were done in black and white because they were shown on their television in black and white, but when you see although it's a very stylized look, it's a really cool design set, so when we have the right opportunity, there's a-lot of this product we want to share."
LINK TO INTERVIEW:
https://youtu.be/y3hcRdD6ZWw?si=EsZT9tJ7-Ukheq8P