Underglaze pencils made with lead-free ceramic colours. They can be used for graphic and design effects. The black pencil is ideal for the permanent marking of trials and will withstand stoneware temperatures. Manufacturer-recommended firing temperature for this range of pencils is 900°C – 1000°C. Fading may occur with some colours at higher temperatures: Test before use. Sharpen with a good quality metal pencil sharpener or sharp knife.