Cuerda Seca

Technique used to separate glazes (or underglazes) during application, preventing them from mixing.

On a bisqued surface, we draw our drawing with a regular charcoal pencil (the lines where we don't want the glaze to stick). The graphite will repel the glaze, so when we apply the glaze or underglaze to the surface (with a brush or with an applicator or rubber bulb) we easily divide the colors without them mixing and leave a perfect line without glaze.

During the firing, the graphite disappears, leaving these lines unglazed and with the color of the clay visible, hence the name “corda seca” - dry rope/line.

We can also use other fats to carry out this process, such as turpentine or linseed oil, even mixed with manganese oxide and a flux so that the line turns black. These fats only work on very low porous surfaces. Sharpie pens also work very well.

The use of graphite or pens can be more practical and we can always combine this technique with the choice of the color of the engobe that was previously applied; this color will be visible in the dry rope.

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