Absorptance is the fraction of light absorbed by a sample.
Absorptance (fraction) = absorbed light/incident light = (incident light - transmitted light)/incident light,
Absorptance % = 100% - Transmittance %.
Absorptance is available as standard on PFXi instruments but not PFX instruments. This is shown as ABS on 'Spectral' results screen.
On the PFXi range, Absorptance is expressed as a fraction, ie. as a value between 0 and 1.
This is not to be confused with Absorbance, which Lovibond Tintometer calls optical density (OD) on the PFX and PFXi ranges.