DID® Diffractive Identification Element
A diffractive optically variable image (developed by SURYS, France) which contains elements that change their color when rotating the image by 90° (the angle of observation is not changed). DID® is transparent at a right angle of observation that makes it easy to read personal data.
![France. Passport issued in 2013: data page. Paper substrate](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/DID_DIFFRACTIVE_IDENTIFICATION_ELEMENT/1l.webp)
a
![France. Passport issued in 2013: the same. DID®. View at an angle of 45º in oblique light](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/DID_DIFFRACTIVE_IDENTIFICATION_ELEMENT/2l.webp)
b
![France. Passport issued in 2013: the same. A color change observed while rotating the image by 90° without changing the angle of observation and illumination. Blue elements become green and vice versa](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/DID_DIFFRACTIVE_IDENTIFICATION_ELEMENT/3l.webp)
c
Fig. 1. France. Passport issued in 2013:
a — data page. Paper substrate; b — the same. DID®. View at an angle of 45º in oblique light; c — the same. A color change observed while rotating the image by 90° without changing the angle of observation and illumination. Blue elements become green and vice versa
![Slovakia. Passport issued in 2014: data page. Polymer substrate](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/DID_DIFFRACTIVE_IDENTIFICATION_ELEMENT/4l.webp)
a
![Slovakia. Passport issued in 2014: the same. DID®. View at an angle of 45º in oblique light](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/DID_DIFFRACTIVE_IDENTIFICATION_ELEMENT/5l.webp)
b
![Slovakia. Passport issued in 2014: the same. A color change observed while rotating the image by 90° without changing the angle of observation and illumination. Green elements become orange and vice versa](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/DID_DIFFRACTIVE_IDENTIFICATION_ELEMENT/6l.webp)
c
Fig. 2. Slovakia. Passport issued in 2014:
a — data page. Polymer substrate; b — the same. DID®. View at an angle of 45º in oblique light; c — the same. A color change observed while rotating the image by 90° without changing the angle of observation and illumination. Green elements become orange and vice versa