Editing Absorbance (section)

===Logarithmic vs. directly proportional measurements===
The amount of light transmitted through a material diminishes [[Exponential function|exponentially]] as it travels through the material, according to the Beer–Lambert law ({{math|1=''A'' = (''ε'')(''l'')}}). Since the absorbance of a sample is measured as a logarithm, it is directly proportional to the thickness of the sample and to the concentration of the absorbing material in the sample. Some other measures related to absorption, such as transmittance, are measured as a simple ratio so they vary exponentially with the thickness and concentration of the material.

{| class="wikitable sortable" style="text-align: center;"
|+ Absorbances and equivalent transmittances
|-
! scope="col" | Absorbance: <math display="inline">-\log_{10}\left(\Phi_\mathrm{e}^\mathrm{t}/\Phi_\mathrm{e}^\mathrm{i}\right)</math>
! scope="col" | Transmittance: <math display="inline">\Phi_\mathrm{e}^\mathrm{t}/\Phi_\mathrm{e}^\mathrm{i}</math>
|-
| 0
| 1
|-
| 0.1
| 0.79
|-
| 0.25
| 0.56
|-
| 0.5
| 0.32
|-
| 0.75
| 0.18
|-
| 0.9
| 0.13
|-
| 1
| 0.1
|-
| 2
| 0.01
|-
| 3
| 0.001
|}