AbstractTwo questions are mainly discussed in this article: (a) how the shape of color order systems is related to different types of chromatic mixtures, and (b) how the opacity or transparency (an aspect of cesia) of the coloring media involved in the mixtures define the results, beyond the established categories of additive, partitive, and subtractive mixtures. The degree of transparency, translucency, or opacity of the material used certainly has a great influence on these processes and in the results obtained, and we could also think that the degree of gloss or matte finish of the surfaces affects the mixtures as well. The underlying idea is that these processes are of a gradualist nature, and that a continuous sequence can be traced between two poles: additive mixture of overlapping lights, on one side, and subtractive mixture of transparent color layers, on the other one. Thus, instead of just three separate or unconnected types of color mixtures, we can postulate a model based upon a gradual sequence between additive and subtractive mixture, with partitive mixture as one of the steps in between. A schematic 3D model of gradual transformation is proposed to encompass different color systems that represent any possible mixture between additive and subtractive.