Overglaze decoration & Underglaze decoration / 釉上彩 & 釉下彩

Overglaze decoration is a method of decorating porcelain, where the coloured decoration is applied after it has been glazed (fired at higher temperature). When the ware is re-fired (at lower temperature) then the colours fuse into the glaze and so the decoration becomes durable. It seems more bulge because of decoration on the glaze and more varied palette of colours is available than with underglaze decoration. 

Underglaze decoration is a method of decorating porcelain in which the decoration is applied to the surface before it is glazed. The glaze will subsequently cover the decoration so that it is completely durable. Moreover, this way allows the production of porcelain with a surface that has a uniform sheen.

釉上彩: 是指在高溫燒製過的瓷器釉面上彩繪紋飾，再經過第二次的低溫燒製而成。因為彩在釉上，摸上去有豐富的凹凸感，也是能容納豐富色釉的施彩工藝。

釉下彩: 釉下彩則是在成型的胎體上用色料繪畫，上釉後以高溫一次燒成瓷器的施彩工藝。其特點是彩在釉下，永不褪脫，光滑平整。

Overglaze decoration / 釉上彩:

Underglaze decoration / 釉下彩: