Deuteranomaly Simulator

Deuteranomaly Simulator previews a color as a viewer with reduced green sensitivity would see it, covering the partial deficiency that is more common than the complete one.

What is Deuteranomaly Simulator?

Deuteranomaly Simulator previews what a color becomes for a viewer with reduced sensitivity in the medium-wavelength cone. It draws the original and the simulated version as a large pair, and the reason the page matters is arithmetic rather than aesthetic: deuteranomaly is the most common color vision deficiency of any kind, so a palette that fails here fails for more people than any other single check on this site.

Deuteranomaly is described as partial rather than complete, and that description carries the important nuance:

• Green sensitivity is reduced rather than absent, so red and green separation narrows instead of closing.
• Deuteranomaly prevalence among men is around one in twenty, which puts it well ahead of the complete deuteranopia it is often confused with.
• What a viewer sees sits between typical color vision and a full deuteranopic view, and where on that range they sit varies from person to person.
• The practical effect on a design is usually the same as for the complete form but milder, meaning reduced hue separation between reds and greens with lightness intact.

One detail of this page is worth stating plainly, because it affects how the result should be read. The simulation is produced by the same matrix the deuteranopia page uses, applied to the 8-bit red, green and blue channels: 0.625 red plus 0.375 green on the first row, 0.7 red plus 0.3 green on the second, and 0.3 green plus 0.7 blue on the third, clamped into the 0 to 255 range. That matrix models the complete deficiency at full strength. So the swatch on the right shows a full deuteranopia projection rather than a graded partial one, and it should be read as a worst case for this group rather than as a picture of the average viewer with deuteranomaly.

That gap between the label and the model is the main limitation, and it comes with a few others.

• No severity control, so the partial range the tool is named for cannot be dialled in.
• One color at a time, with no palette view.
• No image simulation on this page.
• The output is the complete-deficiency projection, which is typically a harder case than a viewer with the anomaly actually experiences.
• The hex value printed is a product of that model, not a measurement of any individual's perception.

Treat the page as a conservative test. If a red and a green survive the full projection, they will separate comfortably for someone with the partial form, and that is a useful property to design against. If lightness is the only thing keeping them apart, the projection will show it, and the fix is to widen that difference until even the complete case holds.

It helps to be precise about the label. This is a partial color blindness page in the sense that deuteranomaly is the partial form of the deficiency, but the swatch shows the complete projection, so green weakness is represented at its limit rather than at a typical level. Used that way it is a conservative check, and a pair that separates cleanly under it will separate for every viewer whose anomaly sits short of the complete case.

How to use Deuteranomaly Simulator

1. Enter the color you want to preview in the swatch field.
2. Compare the original swatch with the simulated result beside it, paying attention to how much separation red and green have lost.
3. Read the hex value under the simulated swatch as a record of the conversion.
4. Decide whether the result is still distinguishable from the other colors it will appear with, remembering that this is the stricter complete-deficiency projection.

When to use Deuteranomaly Simulator vs related tools

Use the deuteranomaly simulator when you want the conservative version of a red-green check, since it applies the complete deuteranopia projection and therefore covers the partial form too. The complete deficiency on its own terms is the deuteranopia simulator, the red end of the same problem is the protanomaly simulator, a whole screen rather than one color is better served by the color blindness simulator, and text colors that survive it are the business of the accessible color pair finder.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.

Frequently asked questions about Deuteranomaly Simulator