Understanding the views Chapter 6
Mastersizer 2000 Page 6-3
Result-over plot (also known as “cumulative oversize”) – similar to the
result-under plot except that the result is in the form “% of sample above a cer-
tain size of particle”. For example by reading the values from the graph (right-
hand axis), the user may be able to determine that 90% of the sample is above
23 microns.
Frequency curve – this is calculated by differentiating the result-under/
cumulative undersize curve. The frequency curve is particularly useful for dis-
playing the results to show the “modes” or peaks in the graph.
The peak of the frequency curve gives the modal diameter, the most com-
monly occurring particle diameter. Note that the frequency curve is scaled to
be approximately the same height as the analysis size band histogram.
Several peaks in the graph indicate that there are distinct sizes of particles
within the sample. This “at a glance” inspection of the results is difficult if the
result is shown as a cumulative plot.
Another use for frequency curves is to compare results from different measure-
ments. Other graph types can be over-plotted but the results may be confusing.
MAN0384-1.0 Mastersizer 2000.book Page 3 Tuesday, March 20, 2007 8:56 AM
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