Situated in the north west transept of Lincoln Cathedral, the magnificent 13^th century rose window, known as the Dean's Eye, was the subject of a major campaign of conservation between the mid 1990s and 2005. As part of the treatment, and after a detailed programme of modelling and testing, a scheme of isothermal glazing was installed, to protect the medieval glass.

Tobit Curteis Associates was commissioned to undertake a long term programme of environmental monitoring in order to evaluate how closely the effects of the completed scheme of isothermal glazing reflected those observed in the tests, and the extent to which the microclimate generated by the glazing reduces the deterioration factors from which the medieval glass is most at risk.

In order to allow an evaluation of the interaction between the modified microclimate and the medieval glass itself to be undertaken, the project is being carried out in close collaboration with the cathedral's stained glass conservation studio. As part of the programme, training in the use of environmental monitoring equipment and software is being provided for the conservators, to enable them to continue a long term programme of monitoring following the completion of the present study.