Audit Neutral Density Filter Certification and Sales
Along with manufacturing our own neutral density filters, EMS offers industry-leading recertification of any competitor’s model.
Our filter certification service sets the industry standard for speed and cost. Contact us today for details.
Along with manufacturing our own neutral density filters, EMS offers industry-leading recertification of any competitor’s model.
Our filter certification service sets the industry standard for speed and cost. Contact us today for details.
Environmental Monitor Service manufactures quality, precision neutral density filters for the most popular opacity monitors. Used for EPA audits and service, our filters are NIST-traceable, fully certified, and manufactured with high-quality optical substrate material. Each filter has a unique serial number and a scanned trace that is dated and signed. The filters are labeled with their value in both optical density and opacity.
The values for filters that EMS sells are found in the table below.
| Nominal Density (O.D.) | % Opacity |
|---|---|
| 0.02 | 5.00 |
| 0.04 | 8.80 |
| 0.10 | 20.57 |
| 0.20 | 36.90 |
| 0.30 | 49.88 |
| 0.40 | 60.19 |
| 0.50 | 68.38 |
| 0.60 | 74.88 |
| 0.70 | 80.05 |
| 0.80 | 84.15 |
| 0.90 | 87.41 |
| 1.00 Up | 90.00 Up (Special Order) |