Hot Mirror filters are used in modern digital video cameras to combat infrared light. Even though most modern cameras have an IR filter in front of the sensor, operators face issues when using ND filters that transmit infrared light, causing color shifts and unwanted flare/contamination. To address this, Hot Mirror IR ND filters combine ND filtration while also reflecting the infrared spectrum via a special coating.
Please store the filter only in its original packaging.
Unlike standard filters, a Hot Mirror IR ND is a dichroic filter made using a special dielectric mirror. Also note that Hot Mirror IR ND filters cannot be stacked together due to their manufacturing specifics. At the same time, standard ND filters can be used together with a Hot Mirror IR ND (however, with very dense ND filters, infrared contamination may start to appear).
When installing Hot Mirror IR ND filters, make sure they are placed first, with the reflective layer facing outward.