Claessens' preprimed Belgian linen canvases are among the finest produced. After an initial inspection of the weave, the fabric is sheared to remove fluff, and vacuum cleaned. For oil-primed linen, this is followed by a 4-step preparation process of pumicing, sizing, priming and coating. The raw fabric is wetted and scrubbed with a pumice stone to give the linen a smooth surface. It is sized with rabbit skin glue to protect fibers from deterioration. A priming coat of zinc white and linseed oil is applied and allowed to dry 3 days. A paint coating of lead-free titanium-based primer and turpentine is applied and left to dry naturally for 10 days. Depending on the style and quality of the linen, some steps may be repeated 2 or 3 times. Until 1995, the oil-primed Claessens linens were primed with lead white pigment, which European regulations no longer allow.