Colour vision preview
The colour vision preview shows the viewport, the board images and the palettes as seen with protanopia, deuteranopia or tritanopia, at 0–100 % severity. Below 100 % it shows the milder forms: protanomaly, deuteranomaly and tritanomaly. The palette check lists the colour pairs that look alike with one of them. New in version 1.1.
The Vision menu
Section titled “The Vision menu”Open Vision in the viewport bar. The button shows the preview in effect: Vision: Normal vision, Vision: Deuteranopia or Vision: Deuteranomaly 60%.
| Control | Does |
|---|---|
| Normal vision | No preview. |
| Protanopia (red-blind), Deuteranopia (green-blind), Tritanopia (blue-blind) | Preview this colour vision deficiency. |
| Severity | 0 to 100 % in steps of 10 %. Below 100 %: the milder forms (protanomaly, deuteranomaly, tritanomaly). |
| Also on the board and palettes | Show the board images, the palettes and the Compare palette rows as seen with this colour vision too. On by default. |
| Palette check | Whether the palette has colour pairs that are hard to tell apart. Show opens the palette check in the board inspector. |
While the board is simulated, a chip at its top says so, for example Deuteranopia preview · 100%, and the status bar reads “Deuteranopia preview in the viewport and on the board”.
The palette check
Section titled “The palette check”The palette check compares every two colours of a palette as seen with protanopia, deuteranopia and tritanopia (CIEDE2000). A pair is flagged when it looks closer than Vision Warn Below (10 by default) with one of them while it is at least Vision Normal Above (20 by default) apart in normal vision. Both are in the settings.
- The board inspector shows it for the board’s key palette, under As seen with: the palette in rows for Normal, Protanopia, Deuteranopia and Tritanopia.
- An image’s inspector shows it under the image’s palette.
Without problem pairs it says As seen with: no problem pairs. Otherwise it lists each pair, worst first, for example:
- “#B8573A and #7A8C6E look alike with deuteranopia (ΔE 7, normally 31)”
Each pair has a Show button that previews that colour vision in the viewport and on the board at 100 %.
What the preview covers
Section titled “What the preview covers”- Viewport: Limner simulates the colour vision in its own viewport pass, after the reference overlay and before the Values and Notan views, so it also shows in Save viewport with overlay images. Off-palette still measures the real colours, and its magenta marker is not simulated.
- Board and palettes: images, swatches and the Compare palette rows, with Also on the board and palettes.
- Measurements: Compare, Match colours and the color script measure the real colours, with or without the preview.
The model
Section titled “The model”The simulation is the model of Machado, Oliveira and Fernandes (2009), applied in linear colour, with the paper’s matrices for each 10 % of severity. It is a simulation for design checks, not a diagnosis.
From Python
Section titled “From Python”set_color_vision() turns the preview on, check_palette_vision() returns the pairs that look alike, and simulate_color(), simulate_color_vision_file() and delta_e2000() work without a viewport. See Python.