Open-Abs: an open source method to quickly measure leaf absorbtance

Visible light is readily absorbed by leaves and used in photosynthesis. This light varies greatly in intensity over time and e.g. within a canopy. As leaves acclimate to light, their absorbtion of light is altered. Not only the total amount of light absorbed is changed, but also the absorbtion of different colours of light may change.


In order to assess the changes that occur in light acclimation, a quick and easy measurement is needed. Up to date, leaf absorbtance measurements have only been possible with expensive and rare specialist equipment, such as a Taylor integrating sphere. As a result, this type of measurement is rarely performed in plant science. Moreover, there is currently no off-the-shelf equipment that can do this measurement in a simple manner.

These type of spheres used to be quite expensive, as well as spectrometers of sufficient resolution and accuracy. With the emergence of 3D printing and low-cost miniature spectrometers, this is no longer the case. These advances open the opportunity to develop an affordable open source integrating sphere system that can measure spectral leaf absorbance. The low cost of such system can increase the number of systems and in turn allow for more (rapid) leaf absorbtance measurements to be taken over time and space, providing opportunity to collect large amounts of data that can give new insight into the development and acclimation of leaves to light.


In this thesis you will develop, build and test a reliable, easy to use, open source method to instantly measure spectral leaf reflectance, transmittance and absorbtance, that can be operated under a range of conditions (e.g. in the field).

Methods and expectations

This project will involve both hands-on and theoretical work:

  • Design and build a dual-integrating sphere set-up
  • Test and improve set-up for spectral leaf absorbance measurements, using miniature spectrometers, on a range of different leaf types in a laboratory environment
  • Develop a proto-type integrating sphere system
  • Test the proto-type system in a greenhouse and field environment, to study leaf acclimation to light in a canopy

This thesis topic or parts thereof are suitable for BSc, MSc or internship projects.

Part of the work can be carried out at Cambridge University (UK), as this project will be done in close collaboration with Dr. Johannes (Wanne) Kromdijk at the Department of Plant Sciences, Cambridge University (UK).