The best and worst films to fall asleep to, according to blue light

To light or not to light: How movie colours can impact your sleep

Light plays a major role in sleep, with darkness helping the body wind down and brightness having the opposite effect. Even ordinary room lighting before bed can significantly suppress melatonin[1], the hormone that signals it’s time to sleep. When this is disrupted, the brain can remain in a more alert “daytime” state, making it harder to fall asleep and reducing sleep quality.

Despite this, many people are still exposed to light at night, often due to screens: nearly three-quarters (74%) keep their phone in the bedroom overnight[2], and 82% of Brits watch TV within an hour of going to sleep[3].

What’s less widely understood is that not all screen light affects the brain in the same way. Movies vary in colour tone, and these subtle differences can influence how the body prepares for sleep. Following the 2026 cinema awards season, colour theory also entered mainstream conversation, with Google searches for “color theory film” rising 1,758% year-on-year, reaching its highest peak on record.

So what matters when it comes to sleep? Research shows that cool, blue-toned light can suppress melatonin for twice as long as other wavelengths and shift the body clock by up to three hours, keeping the brain more alert when it should be winding down[4]. In comparison, warmer light is less disruptive to the body’s natural pre-sleep process[5].

The takeaway? Your bedtime film isn’t just entertainment; it shapes how you drift off – and warmer tones may make the transition a little easier.

The best film genres for inducing sleep, based on lighting

We wanted to go one step further and explore which film genres are most sleep friendly based on their lighting. After all, we all have a favourite genre but does yours actually help you wind down, or keep you more alert than you realise?

Our research found that fantasy films help you sleep the best, with 40% of the fantasy films listed in the research classified as ‘warm’ or ‘very warm’, one of these being The Lord of the Rings: The Fellowship of the Ring.

To explore this, we analysed our Snooze Scores across 100 films to see which genres most consistently feature warmer tones. These include:

Which film’s lighting style has produced the most sleep-friendly films over time?

Film style has evolved significantly over the years, so we wanted to explore how colour palettes have changed – and which decades may produce more sleep-friendly films. These include:

We found that the 1960s produced the highest number of sleep-friendly films, with The Sound of Music (1965) ranking highly. This was followed by the 2020s and then the 2010s.

What do the experts say?

To delve deeper into exactly why our brains respond differently to light before we hit the hay, we partnered with registered GP and sleep specialist Dr Deborah Lee at Dr Fox Online Pharmacy, who said: “Sleep is regulated by the effects of light falling on the retina (the back of the eye). This is the fundamental basis of sleep as part of our circadian rhythms. As night falls, the eye detects darkness, melatonin suppression stops, the SCN allows the pineal gland to produce melatonin, and you feel sleepy again. This is telling your body it is time for sleep.”

“Studies show that blue light, which has a short wavelength, is 2-3 times more efficient at preventing melatonin than other light with longer wavelengths[6].

“Warmer tones of light, such as red and orange, that mimic the setting sun, are best when trying to sleep. They do not suppress melatonin production and can reduce sleep inertia, which is waking feeling groggy in the morning.”

“If you want to watch a film to help you sleep, choose one with muted visuals, that has colours which are warm and soft such as pink, terracotta, grey and sage green. I would suggest for sleep, you need a slow paced film. Action movies, cliffhangers and thrillers raise the adrenaline and are not conducive to sleep.”

Sit back, relax, and watch films on Letterboxd

To help you discover films that may support a more relaxing viewing experience, we’ve created our own curated list on Letterboxd featuring the sleep-friendliest titles from our analysis, all in one place for easy access. You can view the list here. 

Data
Google Glimpse was used to identify all search data, using a worldwide population. This was sourced and correct as of 12.04.2026.

Sources
[1] PubMed
[2] Index Digital
[3] YouGov
[4] Harvard Health
[5] PubMed
[6] Journal of Applied Physiology

Methodology
How the colours were selected and extracted:
We analysed a sample of 100 films, selected through desk research looking at:

• Films commonly recommended as “sleep-friendly” or good to fall asleep to
• The most popular films of all time
• Films currently available (or recently available) on Netflix
• Films frequently discussed for their strong or distinctive colour palettes

To extract visual data, we used Shotdeck to pull a selection of random stills from each film. These stills were then uploaded into Adobe Color, which automatically generated five dominant colour themes per image, producing five corresponding hex codes. This process ensured a consistent, standardised approach to capturing each film’s colour palette.

How we determined whether a film is warm or cool:
Each film’s colour palette was then scored on a 0–100 scale based on how visually calming it may be before sleep, with higher scores indicating more relaxing, sleep-friendly visuals and lower scores indicating more stimulating or visually intense imagery.

To calculate this score, each colour was broken down into three key properties: hue (colour family), saturation (intensity), and brightness (lightness). These were used to generate two weighted sub-scores.

The first sub-score, hue warmth (70% weighting), measures how warm or cool a colour is. Warm tones such as reds, oranges, and yellows score higher, as they are associated with softer, ambient lighting such as firelight or sunset. Cooler tones such as blues and cyans score lower, as they are more commonly linked to daylight and have been shown to be more stimulating to the circadian system. Highly desaturated or greyish tones sit closer to the midpoint, as reduced saturation lessens the influence of hue on perceived warmth.

The second sub-score, brightness comfort (30% weighting), evaluates how visually comfortable a colour is based on its lightness. Mid-range brightness levels (around 45%) score highest, as they resemble dim, ambient lighting conditions that are typically associated with relaxation. Very bright colours tend to score lower due to increased visual stimulation, even if they are warm in tone, while very dark colours also score slightly lower due to reduced visual clarity. Each film’s final score is calculated by averaging the scores of its five extracted colours, producing an overall “sleep-friendliness” rating.