Interface Materials & Layers

Interface materials in iOS create relationships between content layers through transparency and blur effects. Each material serves to establish a visual hierarchy and guide attention.

Materials work together to define how interface elements relate. From navigation bars to background elements, the careful use of different materials helps organize information and create intuitive depth.

Core materials work in harmony: regular material provides the foundation, thin and ultra-thin create transitions, while chrome materials maintain orientation in navigation elements.

Essential relationships include:

• Upper layers using thicker materials for prominence
• Background elements employing ultra-thin for depth
• Navigation utilizing chrome for consistent wayfinding
• Content areas balancing regular and thin materials^[1]

Each iOS material holds unique properties that shape how it interacts with light, motion, and content beneath. Like sheets of varying translucency, these materials respond differently to the digital environment around them.

A material's properties determine its personality in the interface. Thick material maintains a strong presence with intense blur and minimal light transmission, while ultra-thin material lets more light pass through, creating ethereal atmospheric effects. These behaviors aren't random — they're carefully calibrated to support natural interaction patterns.

Core properties include:

• Light transmission: how much underlying content shows through
• Blur intensity: degree of background content diffusion
• Vibrancy: how colors and contrast adapt to the background
• Motion response: behavior during scrolling and interaction

Material hierarchy in iOS interfaces creates clear visual organization through layering. Different materials work together to establish a natural order, helping users understand which elements are more important or interactive.

Higher layers in the interface typically use thicker materials to draw attention, while lower layers use thinner materials to recede. Chrome material marks navigation points, creating consistent anchors throughout the interface experience.

Sequential layering follows specific patterns for clarity. Modal sheets use thick material to separate from the main interface, while background elements employ ultra-thin material to provide depth without distraction.

Key hierarchy patterns:

• Primary actions using thicker materials
• Secondary content using regular materials
• Supporting elements using thin materials
• Background using ultra-thin materials

Blur effects give iOS materials their distinctive visual character and functionality. Each material type applies blur differently — from the intense diffusion of thick materials to the gentle haze of ultra-thin ones.

Blur intensity directly impacts content legibility and hierarchy. Strong blur effects help separate overlaying content, while subtle blur maintains context by letting underlying elements show through. The blur effect responds dynamically to user interaction and content changes.

Key blur characteristics:

• Intensity varies by material type
• Adapts to background content
• Changes with scrolling motion
• Maintains legibility across modes

Transparency in iOS materials creates depth while maintaining content legibility. Light transmission levels vary across material types — from the higher transparency of ultra-thin materials to the controlled clarity of regular ones.

The key to effective transparency lies in its contextual behavior. Materials adjust their transparency based on background content complexity and contrast. This adaptive behavior ensures text remains readable while maintaining the material's characteristic visual effect.

System materials automatically balance transparency with vibrancy effects. When transparency increases, vibrancy adjusts to maintain optimal contrast for overlaying content, creating harmonious layering that works across different contexts and color schemes.

Essential transparency considerations:

• Content legibility requirements
• Background complexity handling
• Light and dark mode adaptation
• Interactive state changes

Light mode materials create distinctive visual effects through their interaction with bright backgrounds. Each material type maintains its unique properties while adapting to ensure optimal contrast and legibility in well-lit interfaces.

In light mode, materials adjust their transparency and blur effects to maintain visual hierarchy. Chrome materials preserve their distinctive appearance, while regular and thin materials soften their effect to prevent harsh contrasts. Background materials become more subtle to avoid competing with foreground content.

Light mode considerations:

• Contrast ratios for text legibility
• Vibrancy adaptation to bright backgrounds
• Shadow subtlety and depth perception
• Material distinction preservation

Dark mode transforms how materials interact with content and backgrounds. Materials maintain their distinct characteristics while adapting their properties to ensure visibility and reduce eye strain in low-light contexts.

In dark mode, materials adjust their transparency and vibrancy to preserve hierarchy. The system increases contrast where needed and softens harsh transitions, while ensuring materials remain distinguishable from one another. These adjustments maintain spatial relationships while creating a comfortable viewing experience.

Dark mode adaptations:

• Reduced transparency levels
• Adjusted blur intensity
• Modified vibrancy effects
• Refined shadow treatment

VisionOS uses materials differently from iOS. The main material, called glass, lets users see their surroundings and virtual content through windows. This glass material changes on its own based on the lighting around it and what's behind it.

Unlike iOS materials, glass doesn't have separate dark and light modes. Instead, it adjusts itself to make sure content stays easy to read no matter what's in the background. Windows in visionOS also use other materials for specific needs: thin material for buttons, regular material for dividing sections, and thick material to stand out above other layers.

Key points about visionOS materials:

• Glass lets surroundings show through
• No dark or light modes needed
• Avoid blocking the view
• Use other materials sparingly

Materials in iOS respond to touches to provide interactive feedback. When users long-press a notification, its material adapts to create an expanded state, showing more content while maintaining the context of the underlying interface.

In the Notification Center, this interaction changes the notification's material properties. The initial compact notification uses regular material, while the expanded state increases blur intensity to emphasize the focused content and separate it from other notifications.

Interactive states:

• Initial notification state
• Expanded preview state
• Dismissal transition
• Background dimming