Transparency

The PDF imaging model supports transparent objects. Transparent objects are processed in two steps:

1. Flattening:

   Divide an area with transparent objects into sub-areas where objects have a constant colour. A sub-area with images or smooth shading is transformed into an image.

2. Blending:

   Combine the colours of overlapping transparent objects into a new colour.

Flatten resolution

Images are flattened at the image resolution. Smooth shades are flattened into 300 dpi images.

Blend colour space

In APPE, the blending colour space is always ignored and transparency blending calculations are done directly in the output colour space.