This is a documentary film produced by the Audio Visual Unit at Leeds University for the Department of Colour Chemistry and Dyeing. It was intended as a review of the methods of predicting colour in the dying process to be used in first year teaching, and also to encourage sixth form pupils to come and study the subject at Leeds. This was the only such course in Western Europe and America. The film begins with a close up of an eye, quickly followed by an animation of coloured lines, with...

This is a documentary film produced by the Audio Visual Unit at Leeds University for the Department of Colour Chemistry and Dyeing. It was intended as a review of the methods of predicting colour in the dying process to be used in first year teaching, and also to encourage sixth form pupils to come and study the subject at Leeds. This was the only such course in Western Europe and America. The film begins with a close up of an eye, quickly followed by an animation of coloured lines, with the commentary explaining the importance of quantum chemistry in the understanding of colour. Dr John Griffiths appears and explains the relationship between colour and molecular structure: how light photons collide with electrons in molecules to absorb certain wavelengths, thereby creating a particular colour. Intertitle - Colour chemistry and computers The commentary explains how different wavelengths give different colours, as interpreted by the brain. Electrons in molecules absorb the energy of particular photons that carry certain colours. Fluorescent light is explained, as energy given off. Until 1856 dying depended upon knowledge of natural dyes handed down. Then knowledge of organic chemistry enabled synthetic dyes. A spectrophotometer is shown in operation, followed by diagrams. A graph plots the absorbance against wavelength, as measured in nanometres (?max), which determines colour. A lecturer inputs the data of molecules into a computer file to make predications of which colour a molecular structure will dye fabric. The computer then prints out the structure of the molecule as a diagram. From these electron orbits can be mapped and a value given, with some applications of this predictability being shown. The film then shows a painter painting some backs of houses as the background of an explanation of conjugation affects and substituent effects: the larger the molecule the bluer the colour. It explains how adding molecules alters the energy gap between electrons, creating different colours. This is shown with textile materials being dyed. Close ups show cloth being dyed by industrial machines. The film switches to a disco where a young woman is dancing wearing the material, now made up into a fashionable garment. The film ends by stating how the scientific principles that are used in dyeing are used within society, showing the example of a lollipop lady in a luminous jacket and a close up of a book being printed. Acknowledgements: there is a list of the many companies that have helped Advisors: Dr F Jones and Dr J Griffiths Made with the help of a grant from the Worshipful Company of Dyers of the City of London