The field of geometrical optics features a broad knowledge base concerning conceptual learning difficulties and student conceptions. However, in contrast to other areas of physics, no widely used standard test instrument exists to assess middle school students' conceptual knowledge of geometrical optics. This is even more true for other areas of the electromagnetic spectrum. For this reason, a concept test was developed for an intervention study to collect preconceptions about visible light as well as preconceptions about infrared radiation in the subject area of reflection and transmission. A pilot study with 108 middle school students preceded final revisions and implementation in the main study of 820 learners aged 12-16. The measurement model is presented for the developed concept test with the subscales 'preconceptions and knowledge about reflection and transmission in visible optics', 'preconceptions and knowledge about reflection and transmission in infrared optics' and 'applied knowledge on reflection and transmission in visible and infrared optics'. The results show that the concept test validly captures the development of preconceptions and knowledge regarding specific aspects of reflection and transmission of the part of the electromagnetic spectrum from 3 µm to 380 nm.