Emulsion samples were placed on a viewing slide (covered with a cover slip in the case of the largest magnification) and observed with an optical microscope (PZO, Poland) equipped with a digital camera. A 20×, 40× and 100× objective lens was used to record sample microstructure. In some cases Sudan II dye (1%, w/v, paraffin oil solution) was used to expose the continuous phase of an analyzed system.