Supply Chain
It looks identical, weighs the same and dyes a shade too pale. Nothing in the process explains it.
— %
Remaining after storage to date
Correcting the dose restores depth but not necessarily the shade, and that is the trap — hydrolysed dye is a different molecule with its own affinity and its own hue, so a heavily degraded dye shifts colour as well as strength and no amount of extra dose brings the standard back. Beyond roughly 10 to 15% loss, re-standardise against a fresh reference by laboratory dyeing rather than by calculation. Humidity, container seal and freeze-thaw all matter as much as temperature for powder products and none appear here. A negative shelf life remaining means the stock is already outside its usable window.
Dye & Chemical Shelf-Life Degradation & Re-titration Modeler — free, with the formula and a worked example, at Textile School.