The colour bar on the left is a graphical representation of the PCT, with the top representing an input value of zero and the bottom an input value of 255.
The scrollable table on the right is a textual representation of the current PCT. The table consists of four columns and 256 entries. The first column is the input grey level. The second, third, and fourth columns are the red, green, and blue output values for the given input value. Either the scroll bar or the arrow buttons can be used to scroll through the PCT. The textual PCT representation is not directly editable.
It is possible to click in either the scrollable PCT window, or the graphical PCT window in order to select a ``Grey Level'' to modify in the Colour Selection area of the PCT Panel. The selected entry becomes the new Grey Level value to edit. Changes to the previous PCT entry are lost unless they were already applied. It should also be possible to select multiple PCT entries to operate on by dragging over a series of list entries.