Colored Glass Filters


Neutral Density Filters (W-ND)

World standard Neutral density filters (W-ND filters) with top quality and excellent optical performance. W-ND series is designed to match the world standard and different from current line of neutral density glass types in terms of thickness and transmittance.
Neutral density filters can be used for various purposes including adjustment of light amount as the light intensity can be controlled without selectively absorbing light with a specific wavelength (405nm, 546nm and 694nm).

Neutral Density Product Portfolio:

HOYA W-ND series HOYA ND series
Standard Thickness t1.0mm* t2.5mm*
Transmittance Specified at 405nm, 546nm, 694nm Average 400-700nm
Internal Transmittance External Transmittance

*Optical characteristics of W-ND/ND series filters are always made by adjusting thickness of the glass.

“W-ND” Series Specification:

W-ND Series of absorption type Neutral Density Filters are widely available with specific OD or transmittance values. They are able to achieve the expansive offering by adjusting thickness based on the characteristics of the mother glass. Neutral Density Filter types make it possible to provide particularly high density filters. The table below reflects the W-ND filter series options by OD value and typical thickness.

Transmission(%)@546nm Optical Density@546nm Standard Thickness(mm)
Mother Glass
50 0.3 2.3 W-ND11
25 0.6 2.3 W-ND5
10 1.0 1.7 W-ND4
5 1.3 2.3 W-ND4
1 2.0 2.0 W-ND3
0.1 3.0 2.1 W-ND9
0.01 4.0 2.8 W-ND9
0.001 5.0 3.5 W-ND9

*All data is mean values of various melts.
*Optical characteristics of W-ND/ND series filters are always made by adjusting thickness of the glass.

Transmittance (Internal Transmittance)

Transmittance (Internal Transmittance): Data

ItemStandard ValueColor specification
(Standard illuminants A)
ThicknessRefractive IndexChemical propertyThermal propertiesMechanical propertiesSpecific gravity