Neutral density filters attenuate light by a constant amount that is, to first order, independent of the wavelength. Wratten ND filters are the cheapest but tend to have more fluctuation with wavelength and a narrower wavelength range than glass ND filters and metallic types. Wratten neutral density filters work by absorption so care must be taken to avoid overheating which can lead to damage to the filter. Wratten ND filters can also be cut easily to bespoke custom sizes in your own laboratory which can be extremely useful.
Old gelatin filters have been replaced by Wratten 2 type filters which are manufactured using a ridged polymer. Wratten 2 filters are more robust and unaffected by water and moisture as gelatin type.
Large 300x100mm sheets available that can be cut to smaller shapes and sizes.
Stock sheets can be cut with a razor or CNC machined to unusual shapes.
Coating options from antireflective to anti-scratch.
Mounting options.
| Name | Density @ 546nm | Transmission (%) @ 546nm | Length (mm) | Width (mm) | Thickness (mm) | Material/Equivalent | Type | Price | Buy |
| FNP0150 | 0.1 | 79 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0250 pdf | 0.2 | 63 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0350 pdf | 0.3 | 50 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0450 pdf | 0.4 | 40 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0550 pdf | 0.5 | 32 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0650 pdf | 0.6 | 25 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0750 pdf | 0.7 | 19 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0850 pdf | 0.8 | 16 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP0950 pdf | 0.9 | 13 | 50 | 50 | 0.1 | Wratten 2 | ND No. 96 Filter |
£37.35
|
|
| FNP09300 pdf | 0.9 | 13 | 300 | 100 | 0.1 | Wratten 2 | ND No. 96 Filter |
£324.50
|
