In the wet ink layer immediately after printing, a certain amount of light is specularly reflected by the layer of water on the ink surface.
On the other hand, in the dry ink layer, the amount of specular reflection is reduced.
Normally, the decrease in the reflected density value obtained as a measurement value due to this change in the amount of specular reflection light is called Dry-down.
Polarization filters are used to reduce the decrease in concentration values due to Dry-down.
