We discuss the fabrication of optical phantoms that will serve as calibration and test standards for a diffuse optical tomographic system developed in our laboratory. For the fabrication of a phantom's matrix, two materials are compared: polyester and epoxy resins. We investigate the capacity to use either of these two resins in the fabrication of a phantom's matrix with different shapes and thicknesses. For the absorbing agent we use India ink and for diffusing agent we choose a fine titanium dioxide (TiO<sub>2</sub>) powder. We test a collimated light measurements set-up to extract: the absorption coefficient <i>μ<sub>a</sub></i> of a purely absorbing medium, and the scattering coefficient <i>μ<sub>s</sub></i> of a purely diffusing medium. We also compare the way <i>μ<sub>a</sub></i> and <i>μ<sub>s</sub></i> add in a solution of absorbing and diffusing media.