Size and Judging Color

by Norm Uress

How Important Is Size When Judging Two Colors?

Very important, more important than most people realize. When two samples are noticeably different in size, your visual system behaves differently, and that alone can make a “match” look like a “mismatch.”

Here’s why:

  1. Your eyes don’t average color the same way on large vs. small areas.

    + A large sample gives your eye more visual information and lets your brain “average” the color more smoothly.
    + A small sample concentrates your attention and exaggerates tiny differences, especially in hue.
    Result:
    A color that looks fine on a 4" × 4" panel can look off on a tiny ½" chip… even when the instrument says it’s the same.
  2. Surrounding colors influence small samples much more.

    Small samples get “polluted” by whatever surrounds them, the table, your hand, the bench top, the shadows, the cut edge of the chip. That makes small chips appear darker, dirtier, or more saturated than larger versions of the same color.

  3. Metamerism becomes more obvious on small samples.

    When two metameric colors shift under a new light source, the shift appears more pronounced when you’re looking at small pieces because your eyes lock onto the edges and contrasts more strongly.

  4. Visual tolerance shrinks as size decreases.

    Small samples “remove forgiveness.” Your eyes expect uniformity across the whole area. One tiny flaw or shift becomes the entire visual experience. Large samples provide context. Small samples provide critique.

  5. Standard practice in color QA/QC: keep them the same size whenever possible.

    In packaging, plastics, automotive, and coatings labs, the rule of thumb is:

    ✅ Match sample sizes whenever possible
    ❌ Never evaluate a 1" chip against a 6" panel unless you must

    If they can’t be the same size, place them on a neutral gray background and mask edges so you’re not comparing stray information.

Bottom Line:

Unequal sample size creates artificial “color chaos.” Matching sizes makes your eyes behave more consistently — and makes your decisions more reliable.

Using DeltaEZ eliminates the guesswork around mismatched sample sizes.

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