How to make figures and presentations that are friendly to color blind people

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How to make figures and presentations that are
friendly to color blind people

• Masataka Okabe and Kei Ito
• with special thanks to
• Cahir OKane

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How common is color blindness?
One in twelve males (8) is red-green color
blind. Type 1 (protanopes) and type 2
(deuteranopes) functional defects in red and
green cone cells, respectively.
People with defects in blue cone cells (type 3
tritanopes) are relatively rare (one in tens of
thousands.)
Red-green color blindness is commoner than AB
blood group. There should be more than TEN color
blinds in the room with 250 people !
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Can color blind people see colors? Do they see
everything black and white?
non color blind
Color blindness is not a total loss of color
vision. But certain ranges of colors are hard to
distinguish.
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How can you see this color ? (common question
-)
A typical confocal picture

• Double-staining with
• red and green signals.
• Not understandable for color blind people !

Lets simulate how color blind people see this.
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Another problem recognition of double positive
cannot distinguish yellow from green
This appears like
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How can you make double staining understandable
both for color blind and for non-color blind
people ?
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red-green double staining
In magenta-green pictures, double positive area
becomes white.
magenta-green double staining
How to convert red channel to magenta? Lets try
with Photoshop.
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How to convert red channel to magenta? REVIEW
Just type ? - 1AC3V!
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Single labeling should be OK !
not so...
Some colors are very difficult to see.
(especially red pictures for protanopes.)
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Even if you dont care about color blinds...

Can you convey more information by making it
color ? It should not be just for aesthetic
purposes. If you just want to show what kind of
label you used (GFP, Cy3, etc.), a sentence in
the figure legend might be enough.
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How about triple labeling?
Good Question Dont show the combined picture
only. Please
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Which is better ?
Faster to relate colors to channels. (Slides?)
green
blue
red
Better tone. Easier to compare staining
patterns. (papers and posters?)
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How about characters and drawings?
Three problems that color blind people suffer
1. Cannot distinguish different
colors.Especially drawings and graphs with red,
orange, yellow, yellow green and green symbols
and lines.
2. Fail to see some objects.Red or magenta
symbols and thin lines over dark blue background.
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How to make slides and figures?
2. Over blue or black background, use only yellow
and white characters. Emphasize with
monochromatic effects like fonts, italics,
hatching, shadows or changing brightness.
4. Avoid simultaneous use of red and green.
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Anything else?
Cannot see red laser pointer well
Green laser pointer is good for color blind
people. The same also for non-color blinds.
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Conclusion
There are always color blind people among the
audience, readers and referees. Please take this
into account when preparing your presentations
(papers, slides, web pages etc.)
Thank you for your cooperation !
Acknowledgements Michina Shiraki (double- and
triple-staining pictures) Kenji Kitahara and
Makiko Ohkido (ophthalmology issue)