The Postal Service recommends that mailers use the ERM III to measure print reflectance and print reflectance difference on delivery point barcodes and Intelligent Mail barcodes, and on FIM bars to avoid interference with readability. The same procedures that apply to measuring address blocks apply to measuring barcodes and FIMs. The Intelligent Mail barcode specification USPS-B-3200 is available at https://postalpro.usps.com/node/2190.
