Short answer
A phone photo is usually built from several frames, not one. The camera merges a burst to cut noise and extend dynamic range, then white-balances, converts colour, compresses the tonal range locally so shadows and skies both hold detail, and applies taste-driven hue and saturation tweaks. Some phones add scene or subject detection. The published details come mainly from Google's research papers; other manufacturers describe their pipelines only in general terms, so specifics vary and are often not public.
Phone sensors have tiny pixels that collect little light, so single frames are noisy and clip easily. Google's HDR+, introduced in 2014 and described in a 2016 paper, captures a burst of raw frames at the same deliberately short exposure so highlights do not clip, aligns them, and merges them into one image with cleaner shadows and more tonal depth. Night Sight extends the approach with longer exposures in dim light. Merging changes colour as well as noise: averaged frames show less colour speckle in shadows, so darker areas can be brightened without turning blotchy.
A merged frame holds more contrast than a screen can show, so the pipeline compresses it. HDR+ uses local tone mapping, brightening shadows while keeping local contrast, then dehazing, then a global S-shaped curve with the sRGB transfer function. These choices change perceived colour: lifting shadows lightens and desaturates dark colours, and a strong S-curve saturates midtones. Google's engineers describe the goal as natural-looking pictures of scenes with strong contrast, and for Night Sight describe deliberately keeping shadows dark so that a night scene still reads as night.
The HDR+ pipeline includes a step that is plainly aesthetic: hue-specific adjustments that shift bluish cyans and purples towards light blue and raise the saturation of blues and greens, to make skies and vegetation more appealing. Other manufacturers describe similar ambitions in marketing terms without technical detail. Some phones also identify scene types or subjects — skies, food, faces — and process them differently, and some let users choose a style that biases tone and warmth. The practical point is that phone colour is designed, not measured, and designs differ between brands and between software updates.
Details for manufacturers other than Google are summarised here only in general terms, because they are not published at the level of an academic paper.
When colour accuracy matters more than appeal — photographing a paint sample, a product, a skin condition for a clinician, a fabric for a supplier — reduce the processing the phone can apply. Use a raw or 'pro' mode if available; turn off scene optimisers and filters; include a grey card or white sheet in the frame; lock exposure on a mid-tone rather than letting the phone brighten the scene; and avoid mixed lighting. Then compare on a calibrated screen. You are still seeing an estimate, but a less opinionated one.
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
FactStrong evidence
Google's HDR+ captures bursts of constant-exposure raw frames, set low enough to avoid blown highlights, and aligns and merges them to reduce noise and increase dynamic range; it was introduced in 2014.
Source: Burst photography for high dynamic range and low-light imaging on mobile cameras (Hasinoff et al., ACM Transactions on Graphics 35(6), SIGGRAPH Asia 2016); Night Sight: Seeing in the Dark on Pixel Phones
FactStrong evidence
The published HDR+ pipeline includes hue-specific adjustments that shift bluish cyans and purples towards light blue and increase the saturation of blues and greens to make skies and vegetation look more appealing.
Caveat: Describes Google's pipeline as published in 2016; later versions and other brands may differ.
FactModerate evidence
Night Sight's designers added an S-curve to its tone mapping and deliberately kept dark areas dark so that low-light photographs still convey that they were taken at night.
Colourwise interpretationLimited evidence
Across manufacturers, smartphone colour is shaped by aesthetic tuning as well as accuracy, and those choices are rarely published in detail.
Based on: Inferred from the detailed Google publications and the absence of comparable technical documentation from most other manufacturers; not a survey of devices.
Caveat: A generalisation; some manufacturers publish more than others and pipelines change with software updates.
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.