Sales and mill people sort whites by cast: blue-white sheets carry heavy optical brightener and violet or blue shading so they look crisp in daylight, balanced or natural whites stay closer to neutral, and cream or ivory grades are deliberately warm. Blue-white grades post high CIE whiteness and strongly negative b*, but they can look harsh or purple under some indoor lamps and lose their sparkle under light with little UV.
Printer wants it blue-white like the competitor's sheet, so push the OBA and walk the violet up until b-star is near minus 10.
Also heard as
- cool white
Related terms
Whiteness
How white a surface looks to the eye, judged across the whole visible spectrum rather than one blue band.
Shading dye
Small dose of blue or violet dye used to cancel the yellow cast of a white sheet and steer its tint.
OBA
Optical brightening agent: a dye that absorbs UV light and re-emits it as blue, making paper look whiter.
b*
Yellow-blue coordinate in CIELAB, positive toward yellow and negative toward blue, watched closely on white papers.