MSQC carries the red plastic glasses, too.

If you have a smart phone, take a picture in black/white. It will show the values very well.

Just what I was going to suggest. I used the colored report covers incl. yellow, blue and green when I was teaching to help my students who were struggling with their reading - these are especially good for students who are dyslexic. Blue seems to help boys a lot in this area. These can usually be found at Wal Mart and other stores that carry office or school supplies.

Yep!! Ok too short so I have to add more!! Here you go!

Go to an Art Supply Store. They have them.

It's not easy to find the transparent folders in stores now.

Actually I really like just using my phone and taking a picture in gray scale or black and white which shows me the value of the fabrics I have picked out together. That way I don't have more things to keep track of.

Of course-- using your phone which is reasonable, conveniently on your person and doesn't add to the clutter of your sewing space-- can and will be misconstrued by shop owners, apparently, and you will have to ask for permission first. . .

small side rant referencing taking photos in brick and mortar stores thread of a week or so back