Ishihara's Tests for Colour Deficiency
Authentic and accurate images of Ishihara's test plates
Just because it's black in the dark,
Oh, doesn't mean there's no colors.
— Laleh (Colors)
Authentic and color-accurate images of Ishihara's test plates for colour deficiency.
I provide high-resolution bitmaps and SVG files for each plate. I also provide the position, size, and color of each circle on each test plate.
Can this information be used to make fakes? Yes, but at least they'll be really good ones. Also, please don't.
If you're interested to learn more about colorblindess and the mathematics behind it, see my Designing for Color Blindness, Palettes for Color Blindness and Math of Color Blindness.
And turn those lines of confusion into understanding!
contents
Below are images of each of the 38 Ishihara test plates. These images are derived from photos that have been carefully color-corrected. Read these details if you're wondering why the background isn't white.
If your monitor is calibrated, the colors will be accurate.
For each plate, I show a simulation of how it would appear to a deuteranope and a protanope.
Simulation results (particularly luminance) depend on which color matrices are used (colorblindness math and simulation details.
There are 2 demonstration plates (1, 38).
There are 12 transformation plates (2–9, 34–37).
There are 12 vanishing plates (10–17, 30–33).
There are 6 hidden plates (18–21, 28–29).
There are 6 diagnostic plates (22–27).
Happy 2026 π Day—
Art for the 5%
Celebrate π Day (March 14th) and enjoy the art — but only if you're part of the 5%.
Go ahead, see what you can't see.
Ishihara's Tests for Colour Deficiency
Authentic and accurate images of Ishihara's test plates photographed (and lovingly color-corrected) from the 38-plate Ishihara's Tests for Colour Deficiency.
I also provide the position, size, and color of each circle on each test plate.
Symmetric alternatives to the ordinary least squares regression
What immortal hand or eye, could frame thy fearful symmetry? — William Blake, "The Tyger"
This month, we look at symmetric regression, which, unlike simple linear regression, it is reversible — remaining unaltered when the variables are swapped.
Simple linear regression can summarize the linear relationship between two variables `X` and `Y` — for example, when `Y` is considered the response (dependent) and `X` the predictor (independent) variable.
However, there are times when we are not interested (or able) to distinguish between dependent and independent variables — either because they have the same importance or the same role. This is where symmetric regression can help.
Luca Greco, George Luta, Martin Krzywinski & Naomi Altman (2025) Points of significance: Symmetric alternatives to the ordinary least squares regression. Nat. Methods 22:1610–1612.
Beyond Belief Campaign BRCA Art
Fuelled by philanthropy, findings into the workings of BRCA1 and BRCA2 genes have led to groundbreaking research and lifesaving innovations to care for families facing cancer.
This set of 100 one-of-a-kind prints explore the structure of these genes. Each artwork is unique — if you put them all together, you get the full sequence of the BRCA1 and BRCA2 proteins.
Propensity score weighting
The needs of the many outweigh the needs of the few. —Mr. Spock (Star Trek II)
This month, we explore a related and powerful technique to address bias: propensity score weighting (PSW), which applies weights to each subject instead of matching (or discarding) them.
Kurz, C.F., Krzywinski, M. & Altman, N. (2025) Points of significance: Propensity score weighting. Nat. Methods 22:638–640.