That is normal, and as it should be. It goes a bit lighter green because the liquid inside has solidified and contracts slightly within the pore structure, making it appear a lighter shade.
Liquid Indicator Technology
Timestrip indicator labels are single use, low cost, patented technology diffusing liquid through a viewing window to reveal how much time has passed since activation or temperature breach
eTimestrip App for pdf reporting
Download our eTimestrip app today. It is compatible with most of our electronic indicators and can be used to generate data report PDF and CSVs to save and share.