Measurement equipment hemispherical light transmission of transparent materials

Wageningen Plant Research Horticulture is seeking commercial partners interested in commercialising measurement equipment for determining the hemispherical light transmission of transparent materials such as structured glass, textiles, plastics.


Greenhouse coverings, screens or solar panels are currently characterised by a measurement of the perpendicular light transmission of the materials. However, the perpendicular light transmission is not a relevant optical characteristic in order to determine the amount of available solar radiation or photosynthetic active radiation available for crops in greenhouses or protected structures.

Structured glass, inhomogeneous textiles such as screens and nettings, structured plastic panels, diffuse plastic films or coatings on glass require a representative measurement of optical properties on large samples due to structure size or inhomogeneity. For that purpose, a new method and measuring device has been developed to properly measure the required optical properties.

The invention

Wageningen University & Research scientists have developed a method and prototype equipment in order to measure the hemispherical light transmission of transparent materials such as structured glass, textiles, plastics, screens and nettings used in horticultural or agricultural application.


Light laboratory

Commercially available equipment for quantifying the hemispherical light transmission of transparent materials is needed in order to get information on the amount of solar radiation and specifically the amount of photosynthetic active light entering through the specific transparent material. Transparent materials applied in horticulture or agriculture are for example greenhouse coverings, such as glass, plastic films, plastic sheets or textiles such as screens and nettings. The hemispherical light transmission of such materials correlates strongly with the average amount of light available in a greenhouse on crop level if the materials are applied. The equipment and measurement method is needed by material producers in order to control their production by measuring relevant optical characteristics and in order to develop new materials. Also the solar industry could benefit from the equipment since the same information is relevant for solar panels.


  • Correct quantification of hemispherical light transmission under different angles of light incidence by transparent materials.
  • Accurate measurement of angular dependent transmission of structured glasses and inhomogeneous textiles.
  • Measurement results strongly correlate with average light level in greenhouses available for crops (see also the publications mentioned under the section Additional information).
  • Relevant for worldwide characterisation of transparent materials used as greenhouse coverings or screens in greenhouses.
  • Relevant information for solar panels can be obtained.

Stage of development

Prototype phase – Method for measurement of hemispherical light transmission has been developed during the past years. Several prototypes of equipment have been build and tested. The current version has been validated and is used to perform measurements on a commercial basis for third parties. It therefore is suitable as the basis for further commercialisation. Existing clients have expressed their interest in purchasing a measurement device.