Test, Test, Test. (Then curate)

There is no substitute for time spent testing. Depending where you are on your glazing journey, this could mean a variety of different things. If you’re using premade glazes, whether bought or from a shared studio, then you still have a variety of thing you can find out. You ideally should know:

What each glaze looks like at various thickness. Some glazes are totally different at different thicknesses, some are identical. You need to know if a glaze result requires a certain application.

What a glazes will look like over various clays/slips/underglazes (if you use them). Some glazes will totally change over different coloured clay. A thinner application of the Floating Blue recipe I use will be very sensitive to the clay it’s on, and it’s good to know that when applying it. I don’t like the colour as much over white clay so I make sure to apply it thicker, but love a thin application over black slip/underglaze. I throw my test tiles with black slip on the reverse to see what a glaze will look like over two clays in one tile.

What the glazes do in combination. It’s not always what you think! It’s nothing like mixing paint, if they mix together you’re combining two recipes to come up with a totally new one, and if they stay separate then you can get things like oil spot patterns where the physical movement of one glaze in the firing will create an entirely new pattern. Test a glaze over and under another glaze to see what works best.

If you have oxide washes, test the glazes over those too. This is similar to combining glazes, but generally more straightforward.

And if you’re wondering whether you should be buying premade glazes or mixing your own, Kara has a great blog post about it. The simple answer is to do what’s right for you. Making your own has a bunch of advantages in the long run, but if you’re doing this in your spare time for fun then it might take quite a while to get to that stage.

If you make your own glazes but you’re not comfortable with the chemistry, then you can try removing the colourant and swapping them for others. Again, this isn’t like mixing paints, you might find it does something unexpected.

If you make your own glazes and understand the chemistry, then you probably don’t need any of my suggestions!

And after all the testing, put all but the best tiles aside for reference later, and only continue with a tiny percentage of them. Curation is just as important as testing.

Most importantly, and I say this knowing full well that everyone will do it anyway, don’t use untested combinations on pieces you like! I know it’s tempting, you have a unique piece and you think you can make it even better by using a new combination of glazes that work perfectly in your head. I’ve done it so many times, and I’ve always regretted it. I know you’ll still ignore it for the first few times, but hopefully it’ll sink in faster for you than it did for me.