Thats what I'm wondering. The article notes that the standard for mass will be changed from a gold plated standard to one that is based on Planck's constant. How are the secondary standards calibrated against a primary standard that is based on a constant that has units of J-s?
My again fearless and hopefully better stated opinion is that NIST would have a working master standard calibrated to say the Planck's Constant you exampled then a working (secondary) standard would be created from this master. A master standard is too precious (costs a lot!) to be handled or otherwise used to any large degree.< And, I completely confess that I forgot what the blazes unit J-s is!P> I recently bought a set of four standards for a spectrophotometer for $134 that have a NIST traceable calibration certificate that lists an absolute value for each tube plus the variability of the lot that they were prepared from. By the example above, I think these are likely a tertiary level standard. Per the manufacturer's procedures in using the standards, if the instrument reading is the calibration value plus or minus the lot variability then the spectrophotometer is functioning to manufacturer's specifications. Otherwise, maintenance service is needed for the spectrophotometer