Related Resources : Ringelmann Scale
There is no definitive chart, rather, Prof. Ringelmann provides a specification; where smoke
The data obtained has definite limitations. The apparent darkness of a smoke depends upon the concentration of the particulate matter in the effluent, the size of the particulate, the depth of the smoke column being viewed, and natural lighting conditions such as the direction of the sun relative to the observer while the accuracy of the chart itself depends on the whiteness of the paper and blackness of the ink used.
In use, the observer glances from the smoke, as it issues from the stack, to the chart and notes the number most nearly corresponding with the shade of the smoke. A clear stack is recorded as No. 0, and 100 percent black smoke as No. 5.
5 Related Topics about Ringelmann scaleBritish Standard .. La Station d'Essais de Machines .. Maximilien Ringelmann .. Scale .. Smoke ..