Display Patterns
Full-screen test patterns for evaluating display color accuracy, contrast, sharpness, HDR capability, and uniformity.
Overview
Display Patterns provides a collection of industry-standard and purpose-built test patterns for evaluating your screen. Each pattern fills the entire display edge-to-edge, hiding the status bar and all UI elements so the pattern is shown without any interference. The patterns are designed to reveal issues that are invisible during normal use — color casts, banding in gradients, uneven backlight uniformity, pixel defects, poor black levels, image retention, and HDR tone-mapping problems.
The tool is useful for:
- Verifying color accuracy after calibrating a display or adjusting True Tone / Night Shift settings.
- Checking for dead or stuck pixels using solid color screens.
- Evaluating OLED black levels and backlight bleed on LCD panels.
- Testing HDR and Extended Dynamic Range (EDR) capability on supported devices.
- Assessing display sharpness and resolution with frequency-based patterns.
- Detecting image persistence (burn-in) or PWM flicker artifacts.
Table Of Contents
- Browsing Patterns
- Pattern Categories
- Viewing A Pattern Full Screen
- Pattern Info Sheet
- Available Patterns
- Notes And Limitations
Browsing Patterns
Patterns are presented in a scrollable grid organized by category. Each category has a header label and contains one or more pattern cards arranged in a two-column adaptive grid.
Each pattern card shows:
- A live preview thumbnail of the pattern, rendered at a small scale so you can see what the pattern looks like before opening it.
- The pattern title below the preview.
- An info button (ⓘ) in the top-right corner of the thumbnail that opens a detailed description sheet.
Tap anywhere on the preview thumbnail to open the pattern full screen. Tap the info button to read about the pattern without opening it.
Pattern Categories
Patterns are grouped into four categories based on what aspect of the display they test:
| Category | Purpose |
|---|---|
| Color Accuracy | Verify that the display reproduces colors correctly, with proper hue, saturation, and white balance. Contains the broadcast-standard color bar patterns (SMPTE, EBU), HDR test patterns, and solid primary colors. |
| Contrast & Black Levels | Evaluate the display's ability to produce deep blacks and differentiate near-black shades. Important for OLED burn-in checks and LCD backlight bleed assessment. |
| Sharpness & Resolution | Test the display's resolving power — its ability to render fine detail and high-frequency patterns without aliasing or blurring. |
| Historical | Classic broadcast test cards that were historically used to calibrate television sets and are still useful reference patterns today. |
Viewing A Pattern Full Screen
When you tap a pattern card, the pattern opens as a full-screen overlay that covers the entire display, including the status bar and safe areas. This ensures the pattern fills every pixel.
- A title overlay with the pattern name appears at the top, and a "Tap to exit" hint appears at the bottom. Both fade out automatically after 3 seconds.
- Tap anywhere on the screen to close the pattern and return to the grid.
For the HDR Test Pattern, opening the pattern also temporarily:
- Sets screen brightness to maximum.
- Disables auto-lock to prevent the screen from dimming during evaluation.
- Enables Extended Dynamic Range (EDR) compositing on the window layer (iOS 16+).
All of these settings are restored automatically when you exit the pattern.
Pattern Info Sheet
Tapping the info button (ⓘ) on any pattern card opens a bottom sheet with:
- A larger preview of the pattern.
- A description explaining what the pattern tests and how to interpret it.
- A "Learn more on Wikipedia" button (where available) that opens the relevant Wikipedia article in an in-app web view.
Available Patterns
SMPTE Color Bars
The SMPTE color bars are the standard test pattern defined by the Society of Motion Picture and Television Engineers. They have been the default color reference for broadcast television in North America since 1978.
Layout:
The pattern is divided into three horizontal sections:
- Top section (67% of height) — seven vertical bars at 75% intensity, from left to right: Gray (75% white), Yellow, Cyan, Green, Magenta, Red, Blue.
- Middle section (8% of height) — a reverse-order row: Blue, Black, Magenta, Black, Cyan, Black, Gray. This section helps verify color phase and alignment.
- Bottom section (25% of height) — contains the PLUGE (Picture Line-Up Generation Equipment) signal: a -I patch (blue-cyan), a white bar, a +Q patch (purple), and a series of near-black patches at carefully specified luminance levels (approximately 3.5%, 7.5%, and 11.4% brightness). The PLUGE region is used to set the black level (brightness control) correctly: the darkest patch should be barely invisible against the background, while the brightest patch should be just barely visible.
When to use:
- Verifying that each color bar is the correct hue and saturation — if any bar has a color cast, the display's color temperature or gamut mapping may be off.
- Setting the brightness (black level) control using the PLUGE bars in the bottom section.
- Checking for color fringing or chroma subsampling artifacts at the boundaries between bars.
EBU Color Bars
The EBU colour bars (also known as 100/0/75/0 bars) are the standard test pattern defined by the European Broadcasting Union. They are the European counterpart to the SMPTE bars and are the default reference for PAL and DVB broadcast systems.
Layout:
Seven full-height vertical bars at 75% intensity, from left to right: White, Yellow, Cyan, Green, Magenta, Red, Blue.
Unlike the SMPTE pattern, EBU bars use a single row of uniform-height bars with no PLUGE section, making them simpler to read but focused purely on color accuracy rather than black-level calibration.
When to use:
- Quick color accuracy check — each bar should appear as a distinct, pure color with no visible tinting or desaturation.
- Comparing your display's color reproduction against a known reference (e.g. a calibrated monitor).
- Verifying that the seven primary and secondary colors are balanced — if Yellow appears greenish or Magenta appears pinkish, the display's white point may be skewed.
HDR Test Pattern (EDR)
The HDR Test Pattern uses Apple's Extended Dynamic Range (EDR) API to push brightness values beyond the standard 0–100% SDR range. On supported displays (OLED iPhones, XDR displays), this pattern can produce luminance levels significantly brighter than normal SDR white.
Layout:
The pattern is divided into three horizontal sections:
- Top section (60% of height) — HDR color bars rendered in the Display P3 color space with EDR boost. The first bar uses an EDR value of 1.5 (150% of SDR white) to test peak brightness reproduction. The remaining bars are 75% saturated primary and secondary colors in Display P3.
- Middle section (20% of height) — eight luminance level patches stepping from pure black (0%) through near-black (5%), shadow detail (10%), middle gray (18%), half brightness (50%), SDR white (100%), and two EDR boost levels (150% and 200%). These test the display's tone mapping and ability to distinguish fine luminance differences across the entire dynamic range.
- Bottom section (20% of height) — peak brightness patches, starting from near-black levels (1%, 2%, 3%), through reference gray (18%), SDR white (100%), and escalating EDR levels (150%, 200%, 300%). The 300% patch represents the maximum EDR value and tests the display's absolute peak brightness capability.
All colors are specified using UIColor(displayP3:) for wide color gamut support, and the view's CALayer is configured with RGBA16Float pixel format and wantsExtendedDynamicRangeContent = true for proper EDR compositing.
When to use:
- Testing whether your device supports HDR / EDR — on a capable display, the EDR patches should appear visibly brighter than the 100% SDR white patch.
- Evaluating tone mapping — the luminance step patches should show smooth, distinguishable transitions. If adjacent patches appear identical, the display may be clipping or compressing the dynamic range.
- Checking near-black shadow detail — the 1%, 2%, and 3% patches should each be distinguishable from pure black. On OLED displays, these test the panel's ability to reproduce very low luminance levels without crushing them to black.
Note: When this pattern is opened, Lirum automatically sets brightness to maximum, disables auto-lock, and enables EDR. These settings are restored when you exit.
HDR-Style Color Bars (SDR)
An SDR approximation of the ITU-R BT.2111 HDR test pattern. This version uses standard sRGB colors (no EDR or wide color gamut) so it works identically on all displays, including those without HDR support. It is useful as a baseline comparison against the true HDR pattern.
Layout:
The pattern has the same three-section structure as the HDR Test Pattern:
- Top section (60% of height) — eight color bars: 100% White, 75% Yellow, Cyan, Green, Magenta, Red, Blue, and Black.
- Middle section (20% of height) — eight grayscale luminance patches from 0% (pure black) through 5%, 10%, 18% (middle gray), 35%, 50%, 75%, to 100% (full white).
- Bottom section (20% of height) — near-black and peak brightness patches: 1%, 2%, 3%, 18% (reference gray), 80%, 90%, 95%, and 100% white.
When to use:
- Evaluating tone mapping on non-HDR displays — the grayscale patches should show smooth, even steps with no visible banding or posterization.
- Checking near-black performance — the 1%, 2%, and 3% patches in the bottom section are designed to test black crush on both OLED and LCD panels.
- Comparing against the true HDR pattern to understand what EDR adds — view both patterns back-to-back on an HDR-capable device.
Solid Colors
Five full-screen solid color patterns are available: White Screen, Red Screen, Green Screen, Blue Screen, and Black Screen (listed in the Contrast & Black Levels category).
Each fills the entire display with a single uniform color at 100% intensity.
When to use:
- Dead pixel detection — a dead pixel appears as a dark spot on a bright background (White, Red, Green, or Blue screens). A stuck pixel appears as a colored dot on the Black screen.
- Backlight uniformity — on LCD displays, the White screen reveals uneven backlight distribution (brighter edges, darker corners, or "clouding"). OLED displays should show perfectly uniform brightness.
- Color tinting — the White screen should appear neutral with no pink, yellow, or blue tint. If the white appears warm or cool, the display's color temperature may need adjustment.
- OLED black level — the Black screen should show true black with no visible glow or gray lift. On OLED panels, this tests that pixels are completely off.
- Primary color purity — the Red, Green, and Blue screens each test one color channel in isolation. They should appear as a pure, saturated color with no visible contamination from other channels.
Black Screen
The Black screen is listed under the Contrast & Black Levels category. It fills the display with pure black (#000000).
When to use:
- Backlight bleed assessment — on LCD displays, view this pattern in a completely dark room. Any light leaking from the edges or corners indicates backlight bleed. IPS panels often show characteristic "IPS glow" in the corners.
- OLED uniformity — on OLED displays, this tests that all pixels are truly off. Any visible glow or non-uniformity may indicate panel degradation.
- Image retention / burn-in check — after displaying static content for a long period, switch to the black screen and look for ghost images of previously displayed elements.
- Ambient light assessment — in various lighting conditions, this pattern helps evaluate how well the display's anti-reflective coating rejects ambient light.
Checkerboard Pattern
A checkerboard pattern of alternating black and white squares (20 × 20 pixels each) filling the entire screen.
When to use:
- Response time and ghosting — scroll or flick the pattern. On displays with slow pixel response times, the high-contrast transitions between black and white squares will produce visible smearing or ghosting trails.
- Pixel inversion and crosstalk — on LCD displays, a checkerboard pattern can reveal pixel inversion artifacts (where adjacent pixels interfere with each other), appearing as a slight shimmer or tint.
- Sharpness and scaling — each square should have perfectly crisp edges. If the edges appear soft or the squares seem to vary in size, the display may be applying unwanted scaling or interpolation.
- Image retention testing — display the checkerboard for several minutes, then switch to a uniform gray pattern to check for afterimages.
- PWM flicker detection — at low brightness levels, the high-contrast checkerboard makes PWM flickering more perceptible if the display uses pulse-width modulation for dimming.
Multiburst Pattern
The Multiburst pattern is a standard display and video test signal consisting of several adjacent panels, each filled with vertical sinusoidal luminance cycles (alternating bright and dark bands). The spatial frequency increases from left to right across the six panels.
Layout:
Six equal-width panels displayed side by side, containing 3, 6, 9, 12, 15, and 18 sinusoidal cycles respectively. Each panel's luminance varies smoothly from white to black following a cosine function, producing a smooth gradient between peaks and troughs rather than hard-edged bars.
When to use:
- Resolution and sharpness evaluation — on a capable display, all six panels should show distinct, well-separated light and dark bands. If the higher-frequency panels (right side) appear as a uniform gray mush, the display lacks the resolving power to reproduce that level of detail.
- Antialiasing and rendering quality — the sinusoidal transitions should appear smooth, not stepped or jagged. Visible banding within individual cycles indicates quantization or poor gradient rendering.
- Contrast at high frequencies — compare the perceived contrast between the leftmost (low-frequency) and rightmost (high-frequency) panels. A quality display maintains contrast even at high spatial frequencies. Significant contrast loss at higher frequencies indicates the display's modulation transfer function (MTF) is rolling off.
- Scaling artifact detection — if the display is running at a non-native resolution or applying any scaling, the highest-frequency panels will show moire patterns or aliasing artifacts.
PM5544
The Philips PM5544 is an iconic television test card designed by Philips in 1968. It was used by broadcasters across Europe, Africa, Asia, and Oceania to calibrate TV sets and verify transmission quality. The pattern is displayed as a full-screen image of the original PM5544 test card.
Layout:
The PM5544 features a central circle with a grid overlay, color bars, grayscale wedges, convergence crosshairs, and geometric elements arranged in a standardized layout. The card was designed so that every element tests a specific aspect of display performance:
- The central circle tests aspect ratio — it should appear as a perfect circle, not an ellipse. If it looks stretched, the display's aspect ratio is incorrect.
- The color bars in the center test color reproduction and saturation.
- The grayscale wedges test the display's ability to reproduce a smooth gradient from black to white.
- The crosshairs and grid lines test geometric linearity — they should appear perfectly straight and evenly spaced.
- The fine detail areas near the edges test resolution and convergence.
When to use:
- As a comprehensive, all-in-one display test — the PM5544 covers aspect ratio, color, grayscale, geometry, and resolution in a single pattern.
- For nostalgia and reference — this is the same test card that millions of viewers saw during broadcast sign-off periods throughout the 20th century.
Notes And Limitations
- The HDR Test Pattern (EDR) temporarily forces maximum screen brightness, disables auto-lock, and enables Extended Dynamic Range on the window layer. All settings are restored automatically when the pattern is closed. EDR effects are only visible on devices with HDR-capable displays (OLED iPhones, XDR iPads, XDR Macs).
- On devices without HDR support, the HDR Test Pattern's EDR patches will appear identical to their SDR equivalents since the display cannot exceed 1.0 luminance.
- Some patterns (particularly the Checkerboard and Multiburst at high frequencies) can reveal PWM flicker sensitivity; results may vary depending on the display's brightness level. Lower brightness often makes PWM flicker more perceptible.
- View patterns in a dim or dark environment for best results, especially when evaluating black levels, backlight uniformity, or near-black shadow detail.
- All patterns cover the full display area including the safe area insets and notch/Dynamic Island region, ensuring every pixel is tested.
- The PM5544 test card is rendered from an embedded image and may not match the display's native resolution pixel-for-pixel, unlike the programmatically generated patterns which render at native resolution.