HN Debrief

Where to Find the Colors Your Screen Can't Show You

  • Design
  • Hardware
  • Photography
  • Developer Tools

The post is a guided tour of display gamut limits. It argues that a lot of the most striking colors people encounter in nature and materials are not just hard to photograph well, they are literally outside what common RGB displays can reproduce. It leans on the familiar CIE color diagram to show where screens miss the mark, then grounds that with examples like green traffic lights, lasers, butterflies, flowers, paints, and high-altitude skies. The core idea is simple. Our eyes reduce spectra to cone responses, so different spectra can look identical, but the three primaries used by most screens still carve out only part of the colors humans can perceive.

If color matters in your product or workflow, stop treating "looks fine on my screen" as a reliable check. Use wide-gamut displays, verify the full capture-to-display pipeline, and remember that lighting, print, and color management can distort results as much as the panel itself.

Discussion mood

Strongly positive and a little delighted. People loved the writing and examples, then used the moment to swap hard-won practical knowledge about display gamuts, projectors, print, lighting, and color science models that are better than the old textbook diagram.

Key insights

  1. 01

    sRGB fails hardest in reds

    The everyday damage from sRGB is not just the famous missing cyan and laser-green corner. It is often the orange, red, and purple range that shows up constantly in flowers, fruit, clothes, skin-adjacent objects, and movie production design. That is why Display P3 can look dramatically more lifelike even when its gamut increase looks modest on the usual diagram.

    If you are choosing displays for design, media, or commerce, prioritize Display P3 support and make sure it is actually enabled. You will see the gain immediately in ordinary content, not just niche demo footage.

      Attribution:
    • adrian_b #1 #2 #3
  2. 02

    Wide gamut without bit depth is incomplete

    A bigger gamut stretches the space between representable colors, so staying at 8 bits per channel can leave visible gaps and force tricks like frame rate control flicker to fake intermediate shades. That does not make wide gamut pointless, but it does mean gamut claims need to be read alongside true 10-bit support and the bandwidth limits of the whole connection path.

    When evaluating monitors or laptops, check for real 10-bit output, not just wide-gamut marketing. Also verify the GPU, cable, refresh rate, and operating system path can carry the mode you think you bought.

      Attribution:
    • szmarczak #1
    • adrian_b #1
    • Aurornis #1
    • ComputerGuru #1
  3. 03

    Lighting quality breaks on deep red

    Display gamut is only one part of color fidelity. Cheap or optimized LED lighting often scores acceptably on CRI while still doing a poor job on R9, the deep-red patch that strongly affects skin tones and how materials look in a room. Several people pointed to TM-30, SSI, and TLCI as more informative metrics when manufacturers provide them, because a single CRI number can hide ugly spectral holes.

    If you care about how products, people, or interiors actually look, audit your lighting specs instead of trusting CRI alone. Poor light can sabotage color decisions before the image ever reaches a camera or monitor.

      Attribution:
    • fmajid #1 #2
    • klabb3 #1
    • RedPanda250 #1
    • orbital-decay #1
  4. 04

    Metamerism is the normal case

    Different spectra matching the same cone responses is not an edge case. It is the mechanism that lets a flower, printed photo, and screen image appear similar despite radically different light distributions. It also explains why matches can fall apart under another illuminant, and why violet versus purple is such a useful mental example of distinct spectra landing on nearby perception.

    Do not assume a color match proven in one environment will survive another. Test important materials under the lighting where customers will actually see them.

      Attribution:
    • grumbelbart2 #1
    • 317070 #1
    • frotaur #1
    • addaon #1
  5. 05

    The classic CIE diagram is outdated shorthand

    That famous horseshoe chart is only a 2D slice of a larger color volume, built from old assumptions about brightness and field of view. More recent work like CIE 2015 and color appearance models such as CIECAM02 handle the fact that perception shifts with luminance and context, which matters more now that wide-gamut and HDR displays expose the limits of the older simplification.

    Use the 1931 diagram for rough communication, not as the last word on visual perception or product decisions. If your work touches HDR, imaging, or display tech, upgrade the mental model as well as the hardware.

      Attribution:
    • SideQuark #1
  6. 06

    Paint matching exposes screen limits fast

    Hardware-store paint systems make the problem painfully concrete. A spectrometer may measure a sample accurately and convert it into CIELAB coordinates, but the on-screen preview still has to squeeze that color into the monitor's supported space, often sRGB. The result is a visible mismatch between sample and preview that ordinary users notice without knowing any color science terms.

    Treat any screen preview of physical color as approximate unless you know the display and software are color managed end to end. For products where exact color matters, keep a physical reference in the loop.

      Attribution:
    • anfilt #1
  7. 07

    More primaries are a pipeline problem

    Adding a fourth or fifth display primary could cover more of human-visible color, but the blocker is not just panel engineering. Cameras, file formats, GPUs, operating systems, editing tools, and content workflows are all built around three-channel assumptions. Print gets around this more easily with extra inks and spot colors because it accepts complexity and specialization that consumer display stacks have resisted.

    Do not expect mainstream multi-primary displays soon unless you also see standards and tooling change around them. In the near term, wider three-primary gamuts and better color management are the practical path.

      Attribution:
    • mceachen #1
    • zahlman #1
    • m3047 #1
    • anfilt #1

Against the grain

  1. 01

    Good photography can beat literal accuracy

    Color loss on screens does not mean images are doomed to feel flat. A careful interpretation of raw sensor data can push limited display space in ways that preserve the emotional punch of a scene, because viewers adapt strongly to context, relative color relationships, and photographic intent. The complaint is often less "screens cannot show it" than "default phone JPEG processing plays it safe and wastes what the medium can do."

    If your images feel lifeless, fix the capture and grading workflow before blaming the display alone. Skilled color work can recover much more of the experience than automatic pipelines suggest.

      Attribution:
    • strogonoff #1
  2. 02

    Blue-green losses may be larger than claimed

    The argument that sRGB's missing blue-green region is perceptually minor may be overstated. One commenter pointed to a more perceptually uniform comparison showing the blue-green area absent from sRGB but present in BT.2020 as a substantial chunk, closer in importance to the missing red-yellow range than the article's geometry implies.

    Be cautious about judging importance from area on the standard chromaticity diagram. If you work with outdoor, foliage, or lighting-heavy imagery, test actual scenes instead of assuming the missing greens are niche.

      Attribution:
    • red75prime #1
  3. 03

    Color memory is too weak to chase extremes

    One blunt pushback was that humans do not retain precise color memory, so hunting for ultra-rare hues is less meaningful than enthusiasts think. On this view, the gap between real objects and display reproduction may be technically real but practically unimportant once the original scene is gone.

    For some products, spending heavily on perfect color may not buy much user value. Decide based on side-by-side tasks like grading, retail, or proofing, not on abstract completeness.

      Attribution:
    • jackbucks #1

In plain english

10-bit ↩
A color format with 10 bits per channel, giving more gradation than the common 8-bit format.
bit depth ↩
The number of discrete numeric steps available per color channel, which affects how smoothly shades can be represented.
BT.2020 ↩
Another name for Rec. 2020, a wide-gamut video color standard.
CIE ↩
Commission Internationale de l'Éclairage, the international body that defines many color measurement standards.
CIECAM02 ↩
A color appearance model that tries to predict how colors are perceived under different viewing conditions and contexts.
CIELAB ↩
A color space designed to be more perceptually uniform than simple RGB coordinates, often used in measurement and industrial color matching.
CRI ↩
Container Runtime Interface, the Kubernetes standard API for talking to container runtimes.
Display P3 ↩
A wider-gamut RGB color space used by many modern phones, laptops, and monitors, especially in Apple devices.
frame rate control ↩
A display technique that rapidly alternates nearby colors to simulate more shades than the panel can physically show.
HDR ↩
High Dynamic Range, imaging and display technology that supports brighter highlights, deeper shadows, and often wider color gamuts.
JPEG ↩
A common compressed image format that reduces file size by discarding some visual information.
metamerism ↩
The phenomenon where different light spectra appear to be the same color because they trigger the eye's cone responses similarly.
R9 ↩
A deep-red test color in color-rendering evaluation that is often omitted from the headline CRI score.
silent substitution ↩
A method of changing light spectra so one class of photoreceptor changes while others stay effectively constant.
sRGB ↩
Standard Red Green Blue, the long-standing default color space for the web and many consumer devices.
SSI ↩
Spectral Similarity Index, a metric used in film and photography to compare how closely a light source matches a target spectrum.
TLCI ↩
Television Lighting Consistency Index, a metric used in broadcast and video to estimate how well a light source will reproduce colors on camera.
TM-30 ↩
A newer color-rendering method for lighting that measures fidelity and gamut using more samples and a more modern model than CRI.

Reference links

Color science and perception

Color models and standards

Projectors and display hardware

Photography, print, and structural color

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    Another article by the same author that commenters recommended and referenced when discussing depth loss in photos.
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  • Fixation
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  • Microsaccade
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