The optic specifications of microscopes are significant at the moment to obtain images to will be analyze and process. The interphase, from the objective lens until the carry-sample, is an element that integrates some optic specifications in the moment to obtain a quality image. Images of different frames using carry-samples of glass and of polymeric membranes are obtained. It is evaluated and characterized the illumination to exit of carry-sample applying image processing algorithms and using some describers of the gray levels distribution and their contrast. Of the results of study the characterization of carry-samples settles down as norm, with the aim of diminishing the error factor when processing a digital image in the analysis of a biological sample.