Purpose: Measuring the Transmittance Properties of Plastic and Glass Specimens in the VISTA Spectrophotometer

Important Notes:

The following procedure provides a practical example of measuring the Transmittance properties of plastic and glass samples using the VISTA Spectrophotometer. This procedure offers a structured approach for measuring the Transmittance properties of plastic and glass specimens using the VISTA Spectrophotometer. It is intended as a guideline to ensure proper instrument operation, calibration, and measurement best practices. While every effort has been made to ensure accuracy and reliability, this procedure does not replace manufacturer specifications, regulatory compliance requirements, or company-specific Standard Operating Procedures (SOPs).
Users should always refer to their organization's Quality Assurance protocols and the HunterLab User’s Manual – Vista with EasyMatch Essentials for formal instructions and compliance with industry standards.

Measuring the Transmittance of Plastic and Glass Specimens in the VISTA Spectrophotometer requires a well-defined procedure to ensure accuracy and repeatability. Here’s the correct procedure:

1. Select the Spectrophotometer

    Ensure that:

• The VISTA Spectrophotometer is verified to be working correctly.
• All accessories are present for the desired measurement.
• The instrument, the standards, and the samples are stabilized in their environment.
• Four (4) hours at STP is recommended.
• Recommend eight (8) hours (re)standardization interval.
• Note that this duration is dependent upon the environment.

2.  Prepare the Sample

• Ensure the Plastic or Glass specimen is meticulously clean and free from contaminants.
• Minimize surface defects to prevent measurement inconsistencies.
• Allow samples to stabilize at the appropriate temperature and humidity before measurement. For exact stabilization times,          refer to your corporate SOP.

3.   Set Up the Spectrophotometer

• Turn on the instrument and allow it to warm up.
• To measure Total Transmittance -TTRAN
  • Select and install the appropriate Sample Holder for TTRAN measurement.
  • For TTRAN Measurement, position the specimen against the right-hand wall of the Vista Sample Compartment, next to the          sphere.
• To measure Regular Transmittance - RTRAN
  • Select and install the desired Sample Holder for RTRAN measurement.
  • For RTRAN Measurement, position the specimen between the sphere wall, right side, and the lens wall, left side, inside the            Vistas’ sample compartment.
  • Do not place a sample in the compartment during this step, as it will interfere with proper calibration.
• Select the appropriate Illuminant – Observer.
  • Illuminant D65 & the 10^o Observer function are the recommended defaults. Consult your SOP for other illuminant-observer        conditions.
• Select Scales and Indices, for example:
  • CIEXYZ
  • CIELAB
  • Haze % (C-2^o)

4. Perform VISTA Standardizations
    The VISTA Spectrophotometer standardization is performed in a single step to ensure measurement accuracy. This process                includes:

• Baseline, Zero, Full-Scale (100%), and Haze Standardizations
  • These calibrations are essential components of the standardization process.
  • Ensure no sample is present in the sample compartment during standardization.
  • This step, often referred to as “Calibrate in Air,” establishes a reference for accurate Transmittance measurements.
• Initiate the Standardization Sequence
  • Follow the instrument prompts to complete the process.

5. Verification of Standardization

• Initiate a Measurement of the 100% Standard (Step 4) as a Sample.

The instrument should return the following values:
L*= 100.00 +/- 0.05
a*= 0.00 +/- 0.05
b*= 0.00 +/- 0.05
 If these values are not achieved, inspect for potential contamination, instrument drift, sudden environmental changes, or improper standardization.
 

6.  Measure the Sample

• Open the door of the Vista Sample Compartment and insert the specimen into the Sample Holder.
• Close the Sample Compartment door.
• Initiate the measurement sequence.

7. Analyze and Interpret the Data

• Transmittance (T%)
• Colorimetric Data (e.g., CIELAB, CIEXYZ values)
• Indices (e.g., Haze, YI, WI, etc.)

8. Quality Control and Repeatability

• Perform multiple readings and use averaging to improve measurement accuracy and repeatability.
• Follow your company's SOP for sample handling and disposition.
• Confirm that the VISTA Spectrophotometer remains in its original calibrated state after measurements.

For further clarification, refer to the HunterLab User’s Manual – Vista with EasyMatch Essentials 2.0.
https://www.hunterlab.com/media/documents/users_manual_for_vista.pdf

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