Conflict of Interest Statement:We declare the following interests: Author DT is on the advisory board of Sectra and Leica/ Aperio. He receives no personal remuneration for these boards. DT has had a collaborative research project with FFEI, where technical staff were funded by them. He received no personal remuneration. DT is a co-inventor on a digital pathology patent which has been assigned to Roche-Ventana on behalf of his employer. He will receive no personal remuneration.
Word Count: 4628Page 3 of 38
AbstractColour is central to the practice of pathology because of the use of coloured histochemical and immunohistochemical stains to visualise tissue features. Our reliance on histochemical stains and light microscopy has evolved alongside a wide variation in slide colour with little investigation into the implications of colour variation.However, the introduction of the digital microscope and whole slide imaging has highlighted the need for further understanding and control of colour. This is because the digitisation process itself introduces further colour variation which may affect diagnosis, and image analysis algorithms often use colour or intensity measures to detect or measure tissue features. The US Food and Drug Administration have released recent guidance stating the need to develop a method of controlling colour reproduction throughout the digitisation process in whole slide imaging for primary diagnostic use.This comprehensive review introduces applied basic colour physics and colour interpretation by the human visual system, before discussing the importance of colour in pathology. The process of colour calibration and its application to pathology are also included as well as a summary of the current guidelines and recommendations regarding colour in digital pathology.