
Never Use White Text on Black: Astygmatism and Conference Slides (2017) - forgotmypw3
https://jessicaotis.com/academia/never-use-white-text-on-a-black-background-astygmatism-and-conference-slides/
======
gnicholas
I work in accessibility and see lots of posts like this one — cautioning the
reader from every doing X because it creates accessibility problems for me.

It may be possible to follow most/all such advice when building an app or
website, but surely it is not possible for presentations (which have to be
consumed in the same format by everyone present). Some may hate dark text on a
light background; others may find that the only suitable format.[1] So when I
read posts like these, I don't view them as imperatives ("never do X") but
rather as data points to be factored into decision-making processes.

This is easiest when the post explains the problem and gives various
alternatives and explains why they provide a better experience. When they just
leave it at "never do X", I'm left wondering whether Y is better than Z or
vice-versa. I wish the author had given more context about why this is bad for
astigmatism, or what sorts of things are better than others (in terms of
ranking alternatives).

1: I hear from people who say that the only decent color scheme for BeeLine
Reader (my text accessibility startup) is bright red and bright blue. But
other people tell me that color scheme is terrible and shouldn't be the
default on my website because it is so bad. You literally cannot please all of
the people all of the time! [edited]

~~~
nabilhat
Like other commentors, I have astigmatism. Something not mentioned by other
commentors; I have highly asymetrical astigmatism. Reading #FFF against #000
(dark on light or light on dark, either way) with both eyes open causes
vividly strobing blue and red visual artifacts.

Stark black text on stark white background can do this, even though stark
white background washes out the color artifacts to some extent. Fortunately,
it's extremely unusual for anyone to lay out a page as #000 text on a #FFF
background.

White text on a black background is a strobing hell. A dead black background
is the perfect place to notice visual artifacts. Blazing white text sets
visual artifacts effectively. Regardless, I use light-on-dark for much of my
work. The problem I run into is that websites often end up being white-on-
black, not light-on-dark. Light (not-white) text on a dark (not-black)
background is pleasant, and my normal configuration for work.

Web design tutorials typically point out that #000 text on #FFF background is
bad, and avoiding such extreme contrasts can be easier on the eyes. For
whatever reason, that bit of know-how seems to vanish as soon as it's flipped
to "dark mode".

~~~
gnicholas
Thanks for the detailed description! It's interesting to think about how one
would meet these needs while simultaneously meeting the needs of people with
scotopic sensitivity (prefer light text on dark background) and vision loss
(require high contrast).

Honestly it seems like this three-way comparison is excellent evidence for the
need for user-configurable reading options. It is unfortunate that on mobile,
there are no browser plugins (except Firefox on Android, which is little-
known, and action extensions on Safari, which is both little-known and does
not support persistently-running plugins). As the world has gone mobile, we've
ended up working/reading in app silos that cannot be made more
accessible/configurable by plugins.

------
DubiousPusher
Speaking from my own disability I'd say I'd much prefer if people used white
on dark text over any use of light background. But this is because my own
issue is with photosensitivity which affects a large number of low vision
users.

In fact I often create white on black content because it is easy for me to
author and read. I also have significant color blindness and am totally unsure
which color combinations are hard for others to read, may not show up on a
projector, may be a faux pas or may be gaurish.

And this is the profound difficulty of creating accessible content. What is
accessible for one is often not accessible for others with a different
disability. Simply saying don't do this or don't do that has long ceased to be
considered a good method of creating accessible content. This has been
abandoned in favor of using a broad suite of tools to validate content meets a
wide array of accessibility needs.

Edit: I have never looked into whether such a tool exists for common slide
presentation apps.

~~~
jankotek
Maybe you find this browser extension useful:
[https://darkreader.org/](https://darkreader.org/)

~~~
DubiousPusher
Thanks. On desktop I use Windows High Contrast Black which is excellent.
Firefox does a pretty good job of modifying web content to follow that theme.
The main issue I haven't solved is mobile browsing. Most mobile browsers don't
allow extensions and the OSes don't have anything like Windows High Contrast
Mode except invent but that's never been a great solution for me.

~~~
jankotek
This extension works on mobile firefox

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astura
I really don't get it... I have severe astygmatism (which caused amblyopia in
infancy) among other visual defects. My glasses do the best they can but my
corrected vision still has a lot of visual defects. My poor vision causes me
trouble with a lot of day-to-day things, but white text on black background is
not one of them. I experimented without my glasses and I still don't have a
preference for black-on-white over white-on-black - they are equal.

Not really a fan of the ranty style without a solution.

On top of that, like another commentor mentioned, people with astygmatism
typically wear glasses or contacts?

~~~
threecreepio
I have irregular astigmatism. In my experience, glasses and normal soft
contacts do very little to correct it. Scleral contacts do a decent job with
the astigmatism, but they have a few other issues.

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pcr0
I didn't think this was a problem as I assumed most people with astigmatism
(myself included) wear corrective lenses or glasses.

~~~
aidenn0
Cylindrical correction in contact lenses tends to be both more expensive and
not as good as glasses, so contact lens wearers with astigmatism may have this
issue.

~~~
arpa
From my own experience, unless you are really, REALLY into sports, glasses are
infinitely much more better in almost every aspect. Sure, if you are young,
you might be afraid you look like a nerd, but trust this old fart, after 25 or
so it does not matter at all; if anything, you are perceived as smarter.

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dwoozle
What’s the alternative? Hopefully not black text on white slides. That’s
terrible for me and others.

~~~
bootlooped
For me, I find that a very dark gray background with a light gray text color
is best. I like dark themes, but I get "ghosting" if the contrast is too
great.

~~~
michaelmrose
This is hard for virtually everyone to read. I don't think making the reading
experience terrible for 99.999% to make it work for 0.001% makes much sense.

~~~
bootlooped
I think what I described is what a lot of dark themes use. For example the NY
Times Android app. Their light text color is not pure white, and the
background is not pure black.

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localhost
Perhaps building an app that synchronizes conference slides to a phone and
allows users to customize the contrast/appearance of the slides would help in
this case?

~~~
zwayhowder
I love that idea. It would let people requiring different contrasts etc see
the content too.

It won't help with pictures as easily, though a few apps these days do full
PDF renders in different colours without much hassle.

I am definitely in the no black background white text camp and on the web I
have a javascript bookmarklet to zap the colour CSS and make everything rather
plain looking. It's not all text for me, but particularly dense text is
unreadable, even with my glasses on.

~~~
localhost
Let me see if I can rally some folks on the Office team to build a PowerPoint
companion app that does this. I think they have a hackathon coming up ...

------
sysbin
I'm surprised the author didn't show examples of what would be preferred for
comparison.

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RenRav
This describes my own personal experience with dark themes, difficult to read.

~~~
limomium
My experience is the opposite. Having switched entirely to light on dark (as
well as adjusting the blue component of my screens to zero), switching the
display of information back to dark on light feels like a nuclear blast of a
million Suns into my eyes.

How can anyone stand staring directly into a bright lamp all day long? Well,
having gotten used to it, you don't notice how unhealthy it truly is.

~~~
RenRav
Working in a properly lit environment, with a blue filter enabled, it
sometimes feels like the papers on my desk are about the same brightness as my
monitor.

At home during the night I have to turn the blue filter up until the monitor
is practically glowing orange-red.

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nullc
I have astigmatism. White on black or black on white both halo. I think both
are equally clear.

It would be somewhat surprising otherwise-- the relevant part of vision for
this is linear and should work the same in both directions. Though if the room
is so dark that my puples will be dilated then that is obviously going to
cause a loss of acuity ... but if that is what the author is going for then
the advice should be to not present in a pitch black room.

In a dimmer room I have a small preference for white (or green/amber) on black
so that the overall brightness isn't blowing out my vision.

Blue focuses noticeably worse, so I have serious trouble reading things like
blue on black or black on blue... esp if the blue is some fancy LED sign or
something that uses a shorter wavelength.

I think articles like this that don't support their advice with some kind of
study of many people ... is pretty low value because it's too likely to just
be repeating the author's own personal preferences and disguising them as
research supported Truths.

Safer advice would be: Some people have poor vision, make your text extra big
and clear even if you could read something less legible.

------
Hnrobert42
Maybe this is victim-blaming, but my suggestion to the post’s author is to
update her prescription. I have astigmatism. This solution worked for me.

~~~
cybwraith
Not all astigmatism is easily corrected with glasses/contacts. I suggest
reading up on irregular astigmatism:
[https://www.warreneyecarecenter.com/better-vision-
correction...](https://www.warreneyecarecenter.com/better-vision-
correction/irregular-astigmatism.html)

~~~
Hnrobert42
That’s interesting. I had not heard of this condition.

I am sympathetic to those with disabilities different from my own. As a
presenter, I would be happy to provide reasonable accommodations. Given the
vast array of visual disabilities, I wonder if there is not some kind of
common denominator solution, like providing a plain text, screen-reader-
compatible version in advance.

I’m actually thinking, I wonder if I should build a service where one: 1\.
Uploads slides. 2\. Gets a QR code. 3\. Puts the QR code on the title slide.
4\. Attendees point their smart phones at the presentation to get a: a.
downloadable copy of the slides b. alternate versions c. other materials like
the presenter’s LinkedIn d. a field for posting questions

If someone reads this and wants to build it, please go ahead.

------
ars
White text on black is my second favorite. Only thing better is green text on
black.

The reason is very simple: There's less light coming from the screen into my
eye.

Every monitor I've ever owned I reduce the brightness to the lowest setting
possible, and they are still too bright.

Green is best because the high resolution parts of your eye only see green. So
the blue and red components of white are just unnecessary extra light.

~~~
bitwize
Oh boy, are you going to love this state-of-the-art new display technology:
[https://c1.staticflickr.com/5/4142/4765726924_0c81d46a5b_b.j...](https://c1.staticflickr.com/5/4142/4765726924_0c81d46a5b_b.jpg)

(Seriously, though, there may be an underlying physiological reason why the
glow of a green phosphor CRT was so pleasing...)

~~~
ars
I always set my IDE to emulate those green CRT's when I can.

But there is an underlying physiological reason, see:
[https://gamesx.com/misctech/visual.htm](https://gamesx.com/misctech/visual.htm)
(the website is very old and has aged badly, but makes the point).

Your eye has no ability to see blue in high resolution.

~~~
bitwize
For me it's Emacs in a terminal, set to a nice chunky bitmap (or bitmap-alike)
font and #7fff7f foreground on black background. :) (For amber, try the X11
color "goldenrod", or #daa520!)

I'm aware of cool-retro-term. It is cool, but not useful for more than five
minutes or so at a time.

------
apocalypstyx
Being unable to stand both white text on black and black text on white, I have
found setting the foreground to black and the background to gray60 (in emacs
and the terminal) is what allows me to look at a screen for hours without
pain.

(Interestingly enough, I too have an astigmatism in one eye, but I don't know
if that's the sole cause of my discomfort.)

------
colorincorrect
that's a bit disappointing, seeing as this format is by far my favourite
because of it being very simple and aesthetically pleasing.

any suggestions? my intuitive response to this would be black on brightly hued
navy blue, but i worry that is also low-contrast, which also causes issues.

can't please everyone!

~~~
michaelmrose
This option sounds like it would be a poor reading for all. You can't please
everyone but it seems like you can figure out how to displease most.

~~~
colorincorrect
[https://imgur.com/a/I1jFrG8](https://imgur.com/a/I1jFrG8) this doesn't seem
that bad, but maybe my phrasing of the colors was inaccurate.

~~~
michaelmrose
I pictured black text on darker blue background. That is readable enough.

------
etaioinshrdlu
As a person with astigmatism and very familiar with halation, I always felt
like white on black was almost equivalent to black on white. It seemed to just
come down to personal preference or mood...

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blunte
I see the white on black ok for a few moments, but soon my eyes can't see
anything (or rather, can't discern shapes and text and such).

The worst are websites with white text on black backgrounds. Arstechnica used
to do this, and I was unable to read more than a paragraph or two. Then when I
would leave and go back to normal sites, I would have all kinds of weird ghost
blocks in my vision (character sized).

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chris_wot
Ouch. Don’t read the NZ Herald’s front page today then!

[https://www.smh.com.au/sport/rugby-union/mourning-has-
broken...](https://www.smh.com.au/sport/rugby-union/mourning-has-broken-kiwis-
cycling-through-seven-stages-of-grief-20191027-p534n1.html)

------
jnwatson
I have significant astigmatism and I prefer light text on a dark background.
When I used a Mac, I found the best solution to get everything dark enough was
to use a light theme and used Mac’s Accessibility Menu to invert the screen
colors. I spend 7-8 hours a day on a dark terminal with light letters.

------
zczc
It's even worse for people with multifocal intraocular lenses implanted after
cataract surgery: they see strong glares and halos around light objects on
dark background (including text), and unlike astigmatism this cannot be
corrected with glasses or contacts

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detaro
With DLP projectors, white on black also causes way worse rainbow effect for
people that are sensitive to that.

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packetized
On mobile, this site has a “toggle high contrast” widget on the left side that
seems to directly contravene the points made in the article.

~~~
gnicholas
Not just mobile — it's on desktop too. I also saw this toggle and thought it a
little ironic. OTOH, this is an opt-in feature that a reader can activate, as
opposed to a presentation that must be absorbed by everyone in the audience
as-is.

~~~
packetized
Agreed, I just found the juxtaposition of the two confusing at first.

------
knolax
I have astigmatism and I have no idea what the author's talking about. I stare
at white on black terminal text all day without issue (maybe it's different
for presentations?). I've also made presentations with white on black text
before and had no problem reading the slides.

~~~
nullc
If the overall environment is really dim, your pupils will dilate. Like
opening the aperture of a camera this will make the area of correct focus
smaller.

... but if the room is so dark that the presentation background alone is all
that is keeping my eyes from dialating, then I'm going to find the
presentation uncomfortably bright.

