Colour Science & Perception
what the eye settles, and what it cannot
Generator

Lightness against colourfulness, in a booth and on a screen

Each arrow is one colour, from what the model predicts under a print in a 2000 lux booth to what it predicts under a display in a dim room. Every arrow points the same way, which is the content: a dimmer surround lowers predicted lightness and colourfulness together, so a proof does not merely differ from the print, it differs in a direction — and that is why proofing standards specify the room and not only the numbers.
Lightness against colourfulness, in a booth and on a screen. Each arrow is one colour, from what the model predicts under a print in a 2000 lux booth to what it predicts under a display in a dim room. Every arrow points the same way, which is the content: a dimmer surround lowers predicted lightness and colourfulness together, so a proof does not merely differ from the print, it differs in a direction — and that is why proofing standards specify the room and not only the numbers.

Drawn at its defaults, in ink, profiles and delivery. It reads 5 options and no others: from, to, labs, show, coverage.

Called by 2 essays

the blast radius of changing it

What it takes to deliver it

The proof is a different object

A soft proof can be made colorimetrically exact and still not match the print, because the print is in a booth at two thousand lux with an average surround and the screen is in a dim room at a fifth of the luminance. The appearance model puts four CAM16-UCS units between them, with no change of stimulus anywhere — larger than the error any rendering intent is arguing about.

 What it takes to deliver it

Measured with an aperture, seen with an eye

A spectrophotometer averages a halftone patch and reports one reflectance. An eye blurs it first and compresses afterwards, and the average of a concave function is below the function of the average — so a resolvable screen looks darker than it measures, by fourteen lightness units at a coarse ruling and by nothing at a fine one. The correction a press applies is the same size and has no viewing distance in it.

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