Professional Detailing2 min read

Narrowband and Broadband Weathering Data: Why the Units Differ

A narrowband irradiance value and a broadband value describe different wavelength ranges. Their numbers should not be compared as though both measured the same quantity, even when the reports use similar weathering equipment.

Updated · NANOLAB Knowledge

The key distinction

Q-Lab explains that narrowband spectral irradiance is expressed per wavelength interval, while broadband reporting covers a specified range. A useful coating comparison preserves that distinction. The selected control point and spectral range belong in the test description, not in a footnote that disappears when the result is copied into marketing material.

Practical checks

  1. Record the wavelength or wavelength band with each value.
  2. Preserve the full units, including any per-nanometre term.
  3. Ask the laboratory whether the two exposure settings can support the intended comparison.

Example

Illustrative example: a supplier table removes the wavelength information to make two reports fit on one line. The simplified table now invites a numerical ranking that the original reports did not support. Restoring the units and method context is necessary before interpreting the apparent difference.

Scope and limits

There is no universal conversion that makes unrelated weathering spectra equivalent for every coating. Do not use a larger irradiance number as a standalone claim of a tougher or more realistic test. The material, exposure cycle and failure endpoint still matter.

Related guidance

Technical references: Q-Lab: Narrowband and wideband irradiance. These sources describe their stated methods or products; they do not certify NANOLAB products or establish compatibility with an unlisted surface.

Ask NANOLAB about the exact product and intended use. Use the current product documentation for formulation-specific instructions.

Professional Detailing2 min read

DLS Particle Size and Electron Microscopy: Why the Numbers Can Differ

Dynamic light scattering reports size through particle motion in a liquid. That hydrodynamic measurement need not match a dimension measured from an image of a prepared particle sample. A difference requires interpretation before either result is rejected.