Neutral Density (ND) Filter Glass

Neutral grey glass is a tinted glass that uniformly absorbs light across the entire visible spectrum. Its core characteristic lies in preserving the hue of transmitted light while merely reducing its intensity, thereby combining light control with decorative functionality.
I. Core Characteristics
Spectral Neutrality: Exhibits consistent absorption rates across red, green, and blue visible light bands, ensuring transmitted light remains free from noticeable colour casts and faithfully reproduces objects' original colours.
Controllable Light Transmission: By adjusting glass thickness or pigment concentration, transmittance can be precisely regulated (typically between 10%–80%), accommodating varying brightness requirements across different settings.
Stable Physical Properties: Exhibits mechanical strength, heat resistance, and chemical stability comparable to standard glass. Certain variants can be further processed into safety glass types such as toughened or laminated glass.
II. Primary Types
Based on manufacturing processes and application contexts, neutral grey glass is categorised into the following two main types:
Type    Manufacturing Method    Characteristics    Suitable Applications
Body-Coloured Neutral Grey Glass    Colouring agents (iron, cobalt, nickel metal oxides) added during glass melting    Uniform colour, high durability, colour does not fade over time    Architectural curtain walls, window/door glass, furniture glass
Coated Neutral Grey Glass
Coating ordinary glass surfaces with metal or metal oxide films
Precisely controls light transmittance and reflectance, with some incorporating low-emissivity (Low-E) properties
Premium building exteriors, automotive glazing, display device protective screens
III. Typical Application Scenarios
Architectural Applications: Utilised as curtain walling, floor-to-ceiling windows, or interior partition glazing. Reduces glare from direct sunlight while preserving colour fidelity of exterior views, creating comfortable daylighting environments.
Automotive Applications: Employed in side windows, rear windows, or sunroofs. Effectively blocks solar radiation to lower cabin temperatures without compromising the driver's perception of traffic signals or surroundings through colour distortion.
Optical and Equipment Sector: Serves as a light-reducing filter for optical instruments (e.g., camera viewfinders, telescopes) or as protective glass for display screens and projection equipment, adjusting brightness without altering image colour.
Home Furnishings and Decor: Crafted into glass coffee tables, bathroom mirror frames, and decorative picture mounts, employing varying shades of grey to achieve a minimalist, contemporary visual aesthetic.