Optically Variable Magnetic Ink (SPARK®, OVMI)
Dynamic color-shifting ink developed by the Swiss company SICPA. Pigments of the magnetic ink used in SPARK® are oriented with the help of the magnetic field so that when the angle of illumination or observation changes, the image changes its color. As result, there is a rolling-bar dynamic effect (a beam of light moving diagonally across the image). Is applied by screen printing, contains ferromagnetic pigments.
![](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/OPTICALLY_VARIABLE_MAGNETIC_INK_SPARK_OVMI/1l.webp)
a
![](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/OPTICALLY_VARIABLE_MAGNETIC_INK_SPARK_OVMI/2l.webp)
b
![](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/OPTICALLY_VARIABLE_MAGNETIC_INK_SPARK_OVMI/3l.webp)
c
![](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/OPTICALLY_VARIABLE_MAGNETIC_INK_SPARK_OVMI/4l.webp)
d
![](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/OPTICALLY_VARIABLE_MAGNETIC_INK_SPARK_OVMI/5l.webp)
e
![](https://static-content.regulaforensics.com/Hardware-products/knowledge_hub/glossary_documents/OPTICALLY_VARIABLE_MAGNETIC_INK_SPARK_OVMI/6l.webp)
f
Fig. 1. Ireland. Official passport issued in 2013:
a — page spread (front endpaper – page 1). Paper substrate (front endpaper), polymer substrate (page 1); b — the same. Zoomed fragment. SPARK® security feature. Nontransparent metallized pigments; c, d, e, f — the same. A rolling-bar dynamic effect (a beam of light moving diagonally across the image). Color shifting. View at different angles of observation