Kinetics modelling of dye cloud formation and its application in colour photography

A numerical single-grain model was designed and programmed quantitatively t o simulate the kinetic process of dye cloud formation based on diffusion an d reactions of oxidized colour developer (quinonediimine, or QDI) in medium . The related reactions, such as deamination, sulphonation with sulphite an d interfacial coupling reaction with solvent dispersion coupler to form dye , were involved as QDI generated on the surface of AgX grain was sphericall y diffusing. A modified model for the intralayer effect of DIR on the forme d dye clouds was also proposed. Both models were verified by experiments an d the fairly good consistence confirmed applicability of the models. With t he models, size and morphology of dye clouds formed under different conditi ons could be simulated and predicted. In addition, more details on the proc ess of dye cloud formation could be obtained from the models, such as distr ibution of dye concentrations in droplets, distributions of projected densi ties, radial distribution of QDI, fraction of developed silver and dye yiel d, etc.