Identifying Craquelure on Paintings
Top Left: Typical 14th and 15 C Italian panel, grain vertical; Cracks on 15th C Italian panels can have two distinct generations or widths, tend to be jagged and have a predominant direction perpendicular to the wood grain.
Top Right: Typical 16th C Flemish panel, grain vertical; Cracks on 16th C Flemish panels tend to be small, orderly, of uniform width, and parallel to the wood grain.
Bottom Left: Typical 17th C Dutch canvas, warp horizontal; Cracks on 17th C Dutch canvas paintings may be straight, jagged, and perpendicular to the warp.
Bottom Right: Typical 18th C French canvas, warp horizontal; Cracks on 18th C French canvas paintings are more random, curved, large, and are usually connected.
None of these statements are always true, but can be used as a general guideline; many characteristics depend on the artist’s individual methods and materials.
Source: directly quoted from Conservation of Easel Paintings, Joyce Hill Stoner and Rebecca Rushfield, 2012.