Fitted Numerical Methods for Singular Perturbation Problems

A dry process high sensitivity imaging film includes a solid, high optical density and substantially opaque film of dispersion imaging material deposited on a substrate. The film of dispersion imaging material comprises a plurality of separate layers of different and substantially mutually insoluble metal components having relatively high melting points and relatively low melting point eutectics, and interfaces between said layers having relatively low melting points. Energy is applied to the film of dispersion imaging material, in an amount above a certain critical value sufficient to increase the absorbed energy in the film material above a certain critical temperature value related to the relatively low melting points of the interfaces, to substantially melt the low melting point interfaces and incorporate the different and substantially mutually insoluble components of the separate layers into the substantially molten interfaces and, hence, to change the film to a substantially fluid state in which the surface tension of the film material acts to cause the substantially opaque film, where subject to said energy, to disperse and change to a discontinuous film comprising openings and deformed material which are frozen in place following the application of energy and through which openings light can pass for decreasing the optical density thereat. Also, means may be associated with the film of dispersion imaging material for retarding the dispersion and change to the discontinuous film, caused by the surface tension, and for controlling the amount of such dispersion and change in accordance with the intensity of the applied energy above said certain critical value to provide continuous tone imaging of the dry process imaging film.