Colour Watcher Tone Ruler Help page
You can have up to 9 Tone Rulers, but only one can be invoked from each Colour Watcher instance. Pressing the various control keys will alter the Ruler fired up from its corresponding Colour Watcher.
The format of the Ruler Text files is pretty simple...
Here is the example of a Zone File: -
Who has focus and is active
It is not obvious when the Ruler has focus and when it will respond to the mouse as there is no window border to indicate its status, so click with care.
When controlling the Ruler from the Colour Watcher program, the arrow keys will change which is the current swatch and then use Control + capital 'C' to get the HEX value copied to the clipboard.
The Ruler is invisible to all normal programs and so the Colour Watcher will display the pixel value of the window beneath the Ruler when you are dragging it or hovering the mouse over the Ruler. It is therefore not possible to 'read' the swatch colour values - use the Hex display instead.
Any swatch defined as Black [rgb(0,0,0)] will be displayed as rgb(1,1,1) for technical reasons!
When you save the Ruler to a file, the holes (if showing!?) will be painted as black - as will any swatch not defined.
The Munsell colour space is not defined by equations, unlike the ones used by Photoshop, and there are only 10 luminosity steps from black to white. Therefore the generated swatch tone value will not necessarily be exactly the same as the pixel value being sampled. Swatches are calculated from the sampled colour down to the lowest swatch and then up to the highest one - generally speaking, for Munsell, the downward ones are more accurate than the lighter one, which tend to go completely out-of-gamut.
It is surprising how small the sRGB colour space is - just view the Munsell model and toggle the 'p' (perception) key to see what I mean.