Borders on cards?

Question: 

Hello! I'm wondering if there is a reason why your card materials don't have colored borders to match Montessori color coding? I was making our own personal religion cards for Mass and I added a border, but I want to buy many of your cards and the perfectionist in me is wondering if I should just make my cards without a border to coordinate with yours. But, that got me wondering if there is a benefit to not having the border and why you went that route.

Julia says:

What a wonderful question! I love the tiny details. As it turns out, different trainers have different preferences when it comes to borders. Originally, cards had borders because they had a backing of some sort (before the age of accessible color printing). I believe that is where it originated. Now, when a color control is needed (as for matching cards or geography folders), we include it on the back. That way the color coding is available to keep items in their sets but does not distract from the topic being isolated. Does that make sense? 

Also, when it comes to sorting, children often find different ways to sort than the ways the adult mind had intended. For example, we may sort items into transportation vs. pets but they might sort those same items by color or shape. So, we may not want to limit them on those materials.