A Notation For Spectral Selectivity

There are three main elements of this notation - films, filters and raster ops. Films are represented as lines with arrow heads at both ends. The placement of the arrow heads represents the spectral sensitivity range of the film. The film type is printed or written just above the line.

Filters are represented as lines with inverted arrows at both ends. The line portion of the filter corresponds to its spectral absorption band. A filter may have multiple spectral absorption bands. Multiple line sections will be drawn, one to represent each of these absorption bands. The filter number will be written above at least one of the lines. When a polarizer is combined with another color filter, both can be represented by the line(s) for the color filter. Filters are drawn below the films to which they are applied.

Raster ops are indicated as ovals with the type of operation identified inside the oval and an optional second image identifier for applying the raster op. The oval should be placed below the film and any filters, and approximately aligned with the left-hand arrowhead for the film line. When a plan for an image is being developed, the most likely choice of raster op should be indicated. Later while experimenting in the image editor, a different operation may prove more effective but an initial, best guess, raster op indication will serve to describe the intent.

The following list shows the three main elements of the notation.