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) and one in 200 females
(0.5) are red-green color blind. (Asian 5,
French and Scandinavian gt10)
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 around 10 color
blind people 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.
Color blind simulator VisCheck
(http//vischeck.com)
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Types of color blinds
non color blind
92
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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 light 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? 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?
Dont show the combined picture only. Please
green
blue
red
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How about characters and drawings?
Four problems that color blind people suffer
1. Cannot distinguish certain colors.Symbols and
lines in blue and violet red, orange,
yellow, yellow green and green
Non color blinds Color blinds
3. Difficult to see emphasized parts. Dark red
characters in black text. (For protanopes, dark
red appears similar to black)
4. Very difficult to tell the name of
colors.Recognition of color difference and
identification of color names are totally
different task.
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Colors difficult to distinguish and identify
The border of color-name categories is not the
same among people.
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Example of colors that are easier to identify

• Red Avoid pure red (RGB100,0,0). Use vermilion
  (RGB80,40,0) or change to orange
  (RGB90,60,0).
• Green Avoid pure green (RGB0,50,0), which is
  confusing with red or brown. Use bluish green
  (RGB0,60,50)
• Light green (RGB0,100,0) and yellow
  (RGB100,100,0) will appear the same to color
  blinds. Avoid using colors between yellow and
  green.

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Line Drawings

• Make lines thicker, symbols larger.
• Use various types of lines and symbols.
• Avoid separate keys. Add labels within the
  drawings.

Bad!
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Graphs
Good!
Bad!

• Use vivid colors with different brightness.Or,
  add hatching.
• Avoid separate keys. Add labels within the
  drawings.

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Dont make a diagram like this
London subway
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Deuteranope simulation...
London subway
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This one is much better.

• Lines are thiker.
• Line names are shown within the map rather than
  in separate keys.

Paris subway
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How to make slides and figures?
Do not convey information with color only. Show
differences BOTH in color and in
shape. redundant coding In addition to
color, use the combinations of - solid and
various dotted lines - various hatching -
circles, triangles and rectangles - alphabets and
numbers - etc. Keep the number of colors to a
minimum.Use combinations of different symbols
with a few, vivid colors rather than a single
symbol with various colors. ???????????? v.s.
???????????? Keep contrast not only in hue
but also in brightness. Make it possible to
communicate without using color name.
First, design figures in gray scale. Then, add
colors as ornament.
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Anything else?
1 Cannot see red laser pointer well
Green laser pointer is good for color blind
people. The same also for non-color blinds.
2 Which is that red cell you are talking
about?
Avoid indicating objects only by color
name. Describe shapes and positions. Use pointer.
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Useful URLs
1 Color Blind SimulatorVischeckhttp//vischeck.
com/ Freeware (Plug-in for NIH Image J Win,
Mac, Unix) Windows (Plug-in for Adobe
Photoshop) Online conversion service Colorfield
Insighthttp//www.colorfield.com/ Macintosh (Pl
ug-in for Adobe Photoshop) 2 Green Laser
PointerDeHarpporte Trading Companyhttp//store.y
ahoo.com/deharpport/ 3 Download the PDF and
PowerPoint files of this presentationhttp//jfly.
nibb.ac.jp/html/color_blind
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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, Tomoko
Hashimoto, Kazuo Ikeo, Olympus Co. Ltd.
(photographs and figures) Kenji Kitahara and
Makiko Ohkido (ophthalmology issue) Kohei Musha
(barrier free trademark)