Most of our two-color and three-color work runs on this rather than an off-the-shelf ink can. We mix rubber-base letterpress ink by hand against a client-supplied Pantone number (or a physical swatch, when the brand’s swatch has drifted from the book over the years — it happens more often than clients expect), and pull a drawdown on the actual job stock before running the full job, because the same ink reads differently on Cotton Rag than on Kraft-Tone.
We keep a mixing log for every commissioned run — ink base, tint ratios, and the stock it was drawn down against — so a repeat order for the same client years later can be matched rather than eyeballed fresh. It’s slower than pulling a stock Pantone-matched premix off the shelf, which is the honest reason it costs more, but it’s the only way we’ve found to guarantee an exact brand color across stocks with genuinely different absorbency.