Spectrum 540 Denim Blue

Spectrum 500 Series Underglazes 501-570 - Spectrum offers a full palette of rich, vibrant colors that are opaque with 3 coats, semi-opaque with 2 coats and semi-transparent with 1 coat. They are compatible for use under most clear glazes. We suggest that you try them with one of their clear glazes (400, 700, 800 or 900 Clear Gloss cone 06/04, 250 Satin Clear cone 06/04, 1100 Clear Gloss cone 4/6, 1120 Clear Satin cone 4/6 or 1200 Clear Gloss cone 9/10). Unlike many other brands of underglaze, Spectrum uses a frit base rather than a slip (clay) base for their underglazes. Underglazes can be applied on greenware or bisque and they can be used with or without a clear glaze covering. When used without a clear glaze cover they have a matte velvet like surface. However, when used without a clear glaze cover they are not considered dinnerware safe because the rough surface can be difficult to clean and can encourage bacteria growth. Spectrum's color chart shows the unglazed color in the upper left half of the tile and the color when covered by a clear gloss glaze in the lower right half of the tile. The color chart samples were fired at cone 05.  Spectrum underglazes generally have good temperature stability up to cone 6 and for many colors to cone 10. When fired hotter than cone 04, you may get small color variations from those shown on our charts, so please test them for your application. Some of their underglaze colors will start to look glossy without any clear glaze cover at cone 5. These softer colors are 507, 530, 537, 538, 544, 552, 560, 567 and 568. Spectrum's underglazes can be intermixed to create your own colors. However, Spectrum recommend not mixing 561, 562, 563, 567, 568, 569 with any of the other colors. These colors are based on cadmium encapsulated stains that do not mix well with other ceramic stain colors. All of Spectrum's underglaze colors are lead-free, A/P non-toxic and dinnerware safe when covered with a dinnerware safe clear glaze.