how to make congo blue gel?

Start here:

Or, go to your local college theatre department and ask if they have any gel scraps you can have. Congo Blue is Roscolux #59.
frollard7 years ago
my guess is you're making the infrared filter glasses -

The easiest way to get it is to order a sample pack from the manufacturer.  search 'gel sample' etc...

Otherwise, making it is a pretty in-depth process involving making the mylar sheet, mixing the dye, and evenly applying it, drying and cutting it...

easier in a hundred ways to buy it.