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The entrapment of fine colloidal paramagnetic (and diamagnetic) particles at magnetic capture centers in the colloid is reviewed. The effect of thermal diffusion on the entrapment from a static colloid is examined in the 1-D and 2-D cases. The latter case allows prediction of captured volumes of colloidal particles. The interparticle effects due to the Helmholtz double-layer electrical interaction and the magnetic dipole-dipole interaction are introduced, and their effect on the 1-D theory is calculated and shown to be of importance. A theory that incorporates the double-layer effect into the 2-D case is presented, and its predicted effects upon the volume of captured particles is examined. The flow of the colloid is introduced, and a framework that allows fine particle capture to be included as a special case of normal size particle entrapment theory is suggested. A diagrammatic means of assessing the effects of thermal diffusion and interparticle effects on entrapment is described.