1964 Topps Baseball
 

I’ve recently started collecting 1964 Topps baseball and I have a question for those who have more experience with this set. In the small collection I now have I have noticed while most of the cards have orange backs, some have red backs. Is this a variation for certain cards or is it random determined by print runs? Thanks.

I checked my set and while I see light and darker orange backs in mine, nothing looks red. Can you post scans of the differences you have

The Venezuelans for that year have black backs