Is having a light theme necessary?

Question

let me just preface this by saying that this question stems from my lack of knowledge about others' opinions regarding this matter, so the only prior knowledge I have is my own preferences.

So, I use dark mode everywhere; every single website is dark for me (using Dark Reader) and every single software I use is in dark mode. If it doesn't have dark mode or at least low brightness colors, I can't use it, even if the sun is directly above my screen.

And so I wonder sometimes why do light themes even exist. I have only seen them IRL for projector use (e.g. schools) or in formal demonstrations because for some reason they're regarded as more "professional" maybe? Plus, I always read people complaints about no dark mode in so many applications but have never heard someone complain about some application not having light mode.

So my question is: is it okay to simply have dark mode and no light mode? Are there any benefits of having light mode? Or any data showing how many people actually use light mode?

(Addendum: After some googling, Discord removed light theme because almost nobody uses it. Is this some very specific case or can it be generalized to almost everything else?)

Answer 1

Is a light theme necessary? No. It's not required. Provided your default (or only) theme complies with accessibility guidelines - meaning the contrast between foreground and background colours is sufficient, and contrasts between separate components on the page is also sufficient to be able to tell them apart) then you're meeting all the requirements as far as usability standards go.

However. Just because it meets accessibility standards that doesn't necessarily mean it meets with user expectations. Just because you don't like light mode that doesn't mean everyone else feels the same. The type of product you're building, the types of users, the devices it's going to be used on should all be considered when deciding on colours and styles.

So don't just make an assumption and leave it there. Follow up your assumption with some research into your actual target audience.

Answer 2

You should have at least one theme that accommodates people with visual impairments (high contrast, big fonts with features for people with dyslexia and compatibility with screen readers)

Before the advent of dark theme in professional apps, user facing apps already had very different styles, because branding seems more important. So there is no universal need to provide a "light theme", as many apps only provide a single theme, which is sometimes neither specifically light nor dark.

Answer 3

No, as others have said, a light theme is not required. I highly recommend to implement both, though. I have been using light theme for nearly everything for years. Then I switched to changing everything to dark (saves energy, home office became a rule - and I sit in a rather dark corner).
Now I have some applications in dark mode and some in light mode. The reason being that most applications do not invest a lot into their dark mode (no, just inverting colors is not a good dark mode), and some just work better for me in light mode (drawing).
On mobile phones a lot of apps switch between light and dark modes depending on the brightness of the environment. Laptops also offer this setting (and it makes sense)

You cannot say as a rule that only dark mode is necessary, just as you cannot say that only light mode is necessary. Discord did an analysis of user behaviour before making their decision. And that is what I strongly recommend. How do your users work? If they use your application in bright sunshine, do not omit a light mode.

People with astigmatism experience stronger distortion of letters in dark mode.

Answer 4

To meet accessibility or usability guidelines it is not a requirement to have a switch for different themes. Dark or light themes are just preferences for both users and designers. There is something to prefer in both and there is no standard, no golden rule to follow as long as you follow usability and accessibility guidelines. I still prefer lighter themes as reading on either low or high contrast darker themes hurts my eyes. There is this article that explains why it might be that you prefer dark and I prefer light. But at the bottom line it says:

... in users with normal vision, light mode leads to better performance most of the time.

_{https://www.nngroup.com/articles/dark-mode/}

The bottom line is that it may be not a requirement to have dark and light mode, it is a very welcome luxury that you website or application can offer to users who have a preference. So if you can afford to implement a light theme besides the dark theme it is very well recommended to spend the time and effort in favor of maybe just a small part of your user base. Some things to keep in mind while offering both themes:

• If the operating system has light and/or dark mode activated you can have themes that change automatically with that setting.
• People that aren't aware of the existence of dark and light themes in general don't have a preference and are probably more accustomed to light themes as that's what they are used to.
• From the article: "It’s unlikely that people will alter the display mode for any random website, but, if a website or an application sees frequent use, it should consider providing this option to its users."