Colour Consistancy Across a Supply Chain

Defining the colour of a product and ensuring its colour accuracy every time are critical to long-term success and accurate communication within a supply chain.

Reliable and repeatable colour test results are the key to ensuring final product quality. They also minimises production costs. Speed of analysis can also be vital for efficient process control. Simplicity of operation helps to reduce error and increase productivity.

Visual Comparators vs. Automatic Measurements

The fundamental difference between the Lovibond® Tintometer Model F, Comparator 3000, Comparator 2000 and the PFXi and RT range is that is that the Model F and Comparators are based on subjective, visual comparison methods (relying to a high degree on the judgment and skill of the operator and hence their perspective, feelings, beliefs and desires) whilst the PFXi and RT ranges rely on automatic, non-subjective measurements (i.e. completely unaffected by the judgment of the operator.)

With operators inexperienced in the area of colour measurement, visual comparison can be more time consuming and less precise than the fast, automatic readings taken with a PFXi and RT. Visual agreement between operators at one site or multiple sites cannot be guaranteed.

The skill/experience of operators, degree of acceptable error, sample preparation time, scale choice and required scale resolution should be carefully considered before making your decision on what instrument to purchase.

Visual systems are of a lower initial cost. However, their limitations should be taken into account when selecting the correct instrument.

Colour Consistency

When comparing visual (subjective) to automatic (non-subjective) colour assessment, the fundamental differences between these methods need to be considered.

Two very basic steps can also be taken to reduce colour communication problems, for example:

  • Are you using comparable, clean cells? Check that cell path length and type (Optical Glass, Borosilicate or Plastic) are identical and the cells are clean and undamaged.
  • Confirm the correct colour scale is selected on your PFX/PFXi instrument? Historically a number of scales are available that report Red & Yellow values. This is a common source of error.

For example; a standard Model F reports Lovibond® Red, Yellow, Blue and Neutral units (RYBN). An AF710 reports AOCS-Tintometer® in terms of Red & Yellow (RY). A PFX/PFXi (depending on model) may be configured to display both RYBN and RY.

Further steps are often instrument specific. We are happy to discuss your specific requirements. Please e-mail or call +44(0)1980 664800.

Accuracy of Measurements

Once compatibility of instruments has been established, it is critical that the long term accuracy of instruments is monitored and maintained.

Two approaches exist historically:

1)    Liquid Reference Standards: High quality liquid samples with known values are used to check that an instrument is reporting the correct figures. The range of Lovibond® colour reference standards includes AOCS-Tintometer®, ASTM, Gardner, Lovibond® RYBN, Pt-Co/Hazen/APHA and Saybolt Colour. Each standard is shipped with a 12-month guarantee of colour stability.

2)    Glass Filters: Conformance filter sets allow quick and simple conformance checks on Lovibond® instruments. Each filter set is supplied with a Certificate of Conformity that confirms they have been manufactured under the control of our ISO 9001: 2000 Quality Management System.

Remote Calibration & Maintenance Service via internet

Since the launch of the Automatic PFXi range of instruments, a new 3rd options exists:

3)    The PFXi series of instruments are installed with an innovative  technology from The Tintometer® Group, RCMSi (Remote Calibration & Maintenance Service via internet.)

RCMSi is the process in which a number of tightly controlled calibration liquids are measured in a 50mm cell via the Calibration function of a PFXi. The measurement data is communicated via the internet to a secure server and compared to Master Data. If the data passes within tolerance, then a certificate of calibration is e-mailed to the user. This allows The Tintometer Ltd to ensure a PFXi instrument is operating correctly and fully calibrated to ISO17025 standards. Thus users can be 100% confident that all PFXi readings are reliable. Certificates of Calibration are provided post process.