Vintage paper is part of the artwork

Scan an 1880s lithograph — a hand-colored fishing-fly plate, an old map, a botanical print — and almost every automatic tool will do the same confident, destructive thing: neutralize the "yellow cast." The cream border turns gray-white, and a century of character is bleached away in a click.

The warmth is the object

Antique plate stock was never white. Measured in Lab, period paper sits around b* +3 to +14 — cream to ivory. That tone is not a defect layered onto the artwork; it is the artwork's ground, as much a part of the object as the ink. A faithful reproduction preserves it. As a rule we learned from decades of print-room practice: for old works, slightly warm is always safer than visibly yellow — but neutral-white is simply wrong.

Two kinds of warm, one lazy fix

The confusion is that scans really do pick up unwanted warmth — from the scanner lamp, from an uncalibrated camera, from tungsten room light. So there are two different warms in every file: the paper's own tone (keep it) and the system's bias (fix it). Naive auto-correction can't tell them apart, so it removes both.

How to tell them apart

There is a measurable difference. On a genuine vintage plate, the warmth lives in the bright base while the dark ink stays essentially neutral — old printing ink is carbon. A true illuminant or scanner cast warms every tonal band equally, midtones included. Compare the two and the file tells you which case you're in. Our engine does exactly this: it estimates the artwork's own base tone, checks whether the midtone neutrals share the warmth, and only then decides — full correction for a real cast, a gentle trim (or nothing) for honest old paper.

And the background must keep its density

Color is only half the trap. Auto-levels are the other: on a vintage plate the cream base is the brightest thing in the image, so a white-point stretch drags the whole background toward paper-white — visibly bleaching it. We anchor only the black end on such works; the plate's background keeps its own density.

Accuracy is not the same as fidelity. The goal is not a colorimetrically neutral file — it's the object, as it is, on archival paper.