These two Inspire tiles show the two different approaches to handling backgrounds: painting the horse first, and painting the background first.
The first approach is perhaps the easiest, since it involves finishing the horse in exactly the same way ceramic horses are done. The tile in the picture just has the base coloring applied. He’ll eventually be a darkly dappled buckskin, so the tile will go through several more layers (and firings) before the clear glaze is applied. With each step, the background will be masked during spraying and then removed for firing. After all the detailing is done, clear glaze will be applied to the horse and fired. At that point there is a completely finished, glossy horse on a bare bisque background.
At that point, the art glaze can be applied to the background using an ordinary paint brush. Since the horse has a hard gloss finish, it is easy to clean any excess art glaze from the horse. That’s really the only trick to this approach. The art glaze must not overlap the clear glaze or it will bleed onto the horse during firing. It’s also a good idea not to apply it too thick close up against the edge of the horse.
The second approach is to paint the background first in Concepts. Because this type of underglaze is hard and semi-glossy after bisque firing, it can be masked over. Ordinary underglazes are so fragile, even after they are fired, that removing latex from them causes scuffing and chipping. They are also porous, so the latex bonds strongly and is often very difficult to remove. Concepts and the other brands do vary, but every one that I have used does hold up well enough to masking. Some colors fire glossy enough that it’s even possible to remove overspray without masking, because it wipes off with a damp sponge.
With background-first tiles, the clear glaze is not added until the entire tile is done. When it is applied, it is added to the entire tile. The areas covered by Concepts don’t usually require a lot of glaze, but they do need some to be truly sealed.
It is also possible to combine all three approaches. The Celtic Pony in the blog header was done this way. His bridle was done with airbrushed Concepts, which were then bisque fired. After that, he was painting just as any other realistically colored horse. Because the Concepts used were quite glossy, and because they were very dark (light colors sink below darker ones in underglaze), I didn’t bother to mask it. I just airbrushed the colors of the face and then wiped away anything on the bridle. After that was bisque fired, I added clear glaze to the entire pony and ran it through a glaze firing. Then the green art glaze was added to the background and the medallion was sent through its second and final glaze firing.
Both systems seem to work equally well, though each does have a drawback. Art glazes are really unpredictable, so it’s possible to get a background too dark or too light or just plain unattractive with the color of the horse. Concepts, on the other hand, give a lot more control over the final look, but the finish is extremely fragile until it is fired so handling it without scuffing some off the edges is a pain. For the most part, it really depends on which look you prefer.