I have recently been making these test tiles to establish a pallete of colours for some new work; combining ceramics and other materials such as wood, metals and plastic etc.
Some of the tests are created using slips and engobes which are shown right. These colours can be used on work as they are; or they can be glazed and fired again - which produces a different, more intense colour. A higher firing temperature also changes the result...
The test tiles below have the right hand side glazed; to easily see the difference between glazed and un-glazed. The other test tiles on the left have more muted glazes to give a wider range of colours to work with.