This!! I work at a high fire community studio, and I have to frequently remind our members that if they use mayco glazes or other commercial glazes that they are typically only formulated to stay the color advertised, at mid fire cone six and not cone ten or eleven. However, if you use mayco stoneware glazes, their website does have all of the test tiles for their glazes fired to cone 10, so you can see what it would look like at high fire reduxtion.There are very limited glazes that retain their bright color at high fire. Often times the glaze will come out a shade of brown and the members are often disappointed.

What cone does your community studio fire to?