Lovibond
®
PFX
i
Series Operator’s Instruction Manual V1.6
Page 30 of 53
Colour Scale
References
ASTM Color
ASTM D 6045, ASTM D 1500
FAC Colour
AOCS Cc 13a-43
Gardner Color
ASTM D 1544, ASTM D 6166,
AOCS Td 1a
Iodine Colour
DIN 6162
Klett Color
AOCS Dd 5-92
Platinum-Cobalt/
Hazen/APHA
Colour
ASTM D 1209, AOCS Ea 9-65,
AOCS Td 1b-64
Saybolt Color
ASTM D 6045, ASTM 156
Performing a Baseline Measurement
It is necessary to take a baseline measurement before carrying out sample measurements
and at intervals during prolonged use. The baseline measurement calibrates the instrument
on both dark and light values.
When performing a baseline measurement, ensure that the
sample chamber is empty.
The Lovibond® PFX
i
automatically takes a baseline measurement when it is first switched on.
This measurement should be repeated at least every 4 hours by pressing the
ZERO
key.
When the baseline measurement is completed, the instrument will go back to the screen that
was displayed before
ZERO
was pressed.
Sample Preparation
Where the measurement is according to a standard test method (see table below), refer to the
method for details of sample preparation. In general, samples should be clear and not turbid,
as suspended matter can cause scattering of the light beam, resulting in low transmittance
values which do not correspond with the sample colour.
Ensure that the end windows of the sample cell are clean and take care to handle cells only
by the sides. Allow viscous samples time to settle, ensuring that air bubbles have dispersed
and there is no movement in the sample.
When samples are measured at elevated temperatures, the cell should also be heated to
prevent the temperature gradient from distorting the light beam. Stirring the sample in the cell
prior to measurement can help to create an even temperature throughout the sample.
