The best size for executing the Spanish pattern is said to consist of a combination of gum tragacanth and flea seed.
In mixing the colors for this pattern, each successive color requires more ox gall than the preceding one. The main, or body, color must also be thicker and mixed with more gall than any of the other colors.
The wavy effect of the early Spanish marbles was not nearly as even as in the later examples, and was almost invariably executed on a relatively heavy laid paper. The distinguishing moiré or watered effect, which sets the Spanish marble apart from all other types, is produced by a series of lines, shading from dark to light, crossing the entire sheet in a diagonal direction, and is the result of the method by which the paper is laid on the size after the colors have been dropped on. The sheet is held at two diagonally opposite corners and is kept in as upright a position as possible. With the sheet inclined toward the left, the corner held by the right hand is lowered until it barely touches the floating color. As soon as the paper starts to fall on the surface, it is slightly agitated with a regular motion, while at the same time being gradually lowered with the left hand until the entire sheet is on the size. If properly done, shaded stripes will appear on the paper when it is removed from t he size. These strips vary in width, depending on how much the paper was agitated while it was being lowered. (152 , 217 , 241 , 369 )