These are the mechanical specifications for the X-Rite Eye-One for color bar artwork:

• Minimum patch size in the scan direction: 10 mm (0.39 in.)
• Minimum patch size in the perpendicular-to-scan direction: 8 mm (0.31 in.)
• Recommended color difference between gapless adjacent patches: > 20 Heidelberg Delta E
• When using a white or black gap to separate like colors, the gap thickness should be 0.5–1.0 mm (0.02 x 0.04 in.)