graphic of dark mode vs light mode user interfaces

Dark Mode vs. Light Mode: Both Sides of the UX Debate


It’s tough to find much of anything that people agree upon these days. In politics, it’s Red vs. Blue. In the superhero world, it’s Marvel vs. DC. In the royal family, it’s Kate vs. Meghan. In the bathroom, it’s whether the toilet paper goes over or under.

And in user experience (UX) design, one of the ongoing debates is dark mode vs. light mode. Which one is better? Whether you’re designing an app’s interface in dark mode or developing dark mode emails, it seems everyone has an opinion. As the folks from Setapp showed us on Twitter, “there are two kinds of people …”

Two kinds of people - illustration of light mode and dark mode interfaces.

You’ll find passionate proponents on both sides and there are plenty of facts and research surrounding every argument. Let’s take a look at some of the most discussed topics.

UPDATE: Email on Acid now offers dark mode open tracking inside our application. Check your analytics to see the percentage of subscribers viewing emails in dark and light modes on specific email clients.


Dark text on a white background (aka light mode) became the standard for most digital interfaces with the rise of word processors, which emulated the look of ink on paper.

One of the first jabs light mode lovers take at dark mode is the claim that it’s not ideal for readability. The vision experts at have this to say on the topic:

“Black text on a white background is best, since the color properties and light are best suited for the human eye … White text on a black background, or ‘dark mode,’ makes the eye work harder and open wider, since it needs to absorb more light.”

So, it seems that science supports light mode for readability, especially when it’s long-form content. But hold your horses! An informal survey of people who use the app Polar to read things like college textbooks found their users overwhelmingly prefer using the app in dark mode. Nearly 90% voted for the dark theme.

When Wired UK interviewed Anna Cox, a professor of human-computer interaction, she explained that the mode you choose isn’t the only thing impacting readability:

“In terms of readability, ensuring a higher contrast between text and background is more important than colour scheme, according to Cox. If the contrast is the same between normal and dark modes, she says we might not expect a difference in legibility.”

Eye strain and blue light

Many dark mode supporters proclaim their loyalty to the dark side largely because they say it is easier on their eyes. Developers, programmers, and anyone who spends a lot of time staring at lines of code tend to feel this way.

Conversely, the information from RxOptical noted that dark mode makes the eyes work harder. That same article, however, went on to admit that it can reduce eye strain in low-light situations.

Blue light exposure throws another twist into this topic. The bright light from our screens is linked to digital eye strain as well as symptoms such as dry eyes, blurry vision, headaches, and sleeplessness. In fact, research published in the science journal Nature found that long-term exposure to bright screens is linked to myopia, or nearsightedness.

Autumn Sprabary at All About Vision takes the middle road on the impact light and dark screens have on our eyes:

“Dark mode successfully cuts glare and reduces blue light, both of which help your eyes. However, dark mode isn’t for everyone, and in some cases, it can actually cause more vision problems than solutions.”

Whether you should read in light or dark mode may depend on the time of day. Chris Hoffman explains on How-to Geek that he thinks nighttime reading calls for darker settings:

“Dark mode is great in low-light environments. If you’re lying in bed reading something on your phone at night, it’s a lot nicer to read white text on a black background rather than have your face illuminated by a lot of bright white light. A dark black screen is a lot less disturbing to anyone else sleeping next to you, too.”

Extending battery life

Low battery phones charging station

As dark mode rose in popularity in recent years, one of the benefits touted in marketing was its ability to save battery life. That’s something that hits home with nearly everyone. We all want to keep our smartphones and tablets alive and away from the charger as long as possible.

But how true is the claim that dark mode saves battery life? Turns out, it depends on how your device’s screen is illuminated.

Mashable reported that dark mode can extend an iPhone’s battery life by as much as 30%. And in 2018, CNET told Android users to turn on dark mode to save power. But the truth is, you’ll only experience energy savings if your phone has an OLED screen (organic light-emitting diode).

Consumer tech writer Brooke Crothers clarified in a article:

“The obvious conclusion is, if you have a smartphone with an LCD (not uncommon) or laptop or tablet with an LCD (almost universal), dark mode has no impact on battery life.”

Crothers explained that devices with OLED screens actually turn off pixels in dark mode, which draws no power, while LCD screens use the same amount of power regardless of dark mode vs. light mode. However, actually turning down the brightness on an LCD does impact battery life.

Mobile Enerlytics found a wide range of potential energy savings with OLED screens. According to their research, it could be anywhere from 1.8% to 23.5% depending on the app you’re using.

The verdict? You may extend your battery life a bit using dark mode, but you probably won’t save enough energy to save the planet.

Email developers on dark mode vs. light mode

Now let’s take on a topic that hits closer to home. How do email developers feel about dark mode vs. light mode? On one hand, they may opt for the darker option in their work and daily lives. But, when it comes to creating emails, dark mode has its challenges.

Search for “dark mode email” on developer message boards like Stack Overflow and you’ll run into plenty of people looking for help dealing with all sorts of issues. Here are just a few of the many questions:

  • “Is there anything that can be done to prevent dark mode from changing our text from black to white?”
  • “Is there any ‘easy’ way to automatically switch the whole HTML to dark mode, whenever possible?”
  • “I am having an issue in the rendering of my custom coded HTML Email template in Dark Mode. The email and all the colors work perfectly fine except this one top header.”

The most frustrating thing about dark mode emails is that clients are inconsistent in the ways they render your emails. Patrick Krupar of laid out the details of that challenge after testing out dark mode emails for himself. Still, he loves dark mode for email enough that he’s willing to work through those challenges:

“I’m a massive dark mode fan, and blindingly-bright email is my nemesis so when I learned about the dark mode in iOS 13, I did the only obvious thing and ordered a brand new iPhone to test things out … Dark mode is coming to HTML email, and I love it! But, it’s another thing to worry about, like using HTML tables for layout wasn’t enough.”

Email on Acid’s own developer, Ed Ball, is also a fan of dark mode and has experienced the challenges first-hand. His advice? Hacking dark mode may not be the best use of your time.

Ed Ball

I really like dark mode! I’ve noticed it creating render issues with emails and developers trying to reverse it with code. But if the reader has their device in dark mode, they’re going to want their emails in dark mode. So, if you alter the email, you’re actually deviating from what the reader wants to see. Designing emails for dark mode is the best way to go, in my opinion.

To learn more about how dark mode is impacting the world of email marketing, check out Pathwire’s dark mode for email survey

Even Great Emails Need to Be Tested

It’s true: Even well-designed emails can break from time to time. That’s why email testing is an important part of sending a successful campaign. Email on Acid tests your email code quickly and accurately, allowing you to preview your design across more than 100 of the most popular email clients and devices. Try us free and start delivering email perfection!

Check Out Our Free Trial

Author: Kasey Steinbrinck

Kasey Steinbrinck is a Sr. Content Marketing Manager for Sinch Email, which includes the brands Email on Acid, InboxReady, Mailgun, and Mailjet. He understands how email and content work hand-in-hand to create a strong strategy. Kasey has also spent time working in traditional media, e-commerce marketing, and for a digital agency.

Author: Kasey Steinbrinck

Kasey Steinbrinck is a Sr. Content Marketing Manager for Sinch Email, which includes the brands Email on Acid, InboxReady, Mailgun, and Mailjet. He understands how email and content work hand-in-hand to create a strong strategy. Kasey has also spent time working in traditional media, e-commerce marketing, and for a digital agency.

1 thought on “Dark Mode vs. Light Mode: Both Sides of the UX Debate”

  1. Frankly speaking, I didn’t even know that there are things called Dark mode and Light Mode. This blog brought light on the topic and finally I have the knowledge on this topic. Thanks for this post.

Leave a Reply

Your email address will not be published. Required fields are marked *