For my keepsake charms, I use press molds to create low reliefs. Often there is some confusion regarding the difference between a raised and an incised image. Here is a resource for exploring these two sculptural techniques.
Incised Feather Pattern, polymer clay and acrylic paint
To incise means to cut or impress a mark into a surface. In the example above, I pressed polymer clay into a mold that had a series of raised lines. The resulting surface of the clay is flat and the lines are impressed into the material. The imprinted pattern is made visible by rubbing a contrasting color into the grooves.
Low Relief, polymer clay and acrylic paint
A low relief has a form that projects out from the background surface. To make the bird in the example above, I pressed polymer clay into a mold that had deep cavities (e.g., like the inside of a bowl). The clay conformed to the empty shapes and created a slightly raised sculptural relief.
Low Relief with Incised Pattern, polymer clay and acrylic paint
In the example above I used two different molds to combine both a low relief and an incised design. First I pressed polymer clay into the feather pattern, incising the delicate lines, and then I pressed the textured clay into the bird mold which created the sculptural relief.
Each bird has a completely different look and feel based on whether I used the overlay of the incised pattern or not. From a distance, the bird on the left may be more readable, whereas the bird on the right has a subtle texture that communicates an ethnic style.
Combining Techniques for Logos
In addition to overlaying relief and incising techniques, I have also used them separately in the same piece. The logo on the left has an incised title and a raised flower. Compare this to the logo on the right that uses only incised lines to create the design.