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Date: 23 September 2023

Time: 18:07

Display screen and film processing quality assurance instruments


Densitometers are calibrated against a traceable Kodak step tablet which conforms to the American National Standards Diffuse Transmission Density - ANSI PH2.19-1986 and ISO 5/2-1985. If your own reference step wedge is included, we also measure and state the diffuse density measurements for this. Densitometers can be adjusted to conform to manufacturer's specification.


Sensitometers - sensitometric strips are produced with typical radiographic film and manual processing under controlled conditions. The resulting film densities are measured on a traceably calibrated transmission densitometer (Type DT1405 with 3 mm aperture). A consistency check to confirm the strips are reproducible is also carried out.


Photometers (luminance meters and illuminance, or Lux meters) are used as an essential part of image display screen quality assurance, e.g. to check conformance with the DICOM standard (GSDF). The photometers can be calibrated to a wide range of values, traceable to national standards. Luminance values offered are 1-1,600 cd - m-2 and illuminance values from 2–17,000 lux both maintaining a colour temperature as close as possible to 2856K.

Contact us

For further information please contact:

  • General enquiries: Tracie Such
  • Technical enquiries: Joanne Johnson, John Lewis

63 Melchett Road
Kings Norton Business Centre
Birmingham, B30 3HP
Telephone: 0121 371 7000

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