M3 measurements

[mstewart]

Just wondering of the reason(s) a offset printer may use M3 with polarizer filter on when measuring colour bars on press sheet. I might be uninformed but I thought M3 was used in the garment industry.

 

[gordo]

M3 simply describes a measurement that is polarized and has UV filtered out. I.e. it’s intended to cut the effect of OBAs and first surface reflections. This may be useful if the instrument's reaction to UV is different than that of the human observer.
Have a look at this presentation: http://www.color.org/events/bressanone/15.Vogh-Bressanone.pdf

 

[mstewart]

Thank you Gordo - stay safe!!

 

[SteveSuffRIT]

M3 is a useful for minimizing or eliminating the affects of ink dry-back or dry-down.
A fresh wet ink will have a much higher density, but as it dries, the density will drop lower. Maybe as much as 0.15 density units (1.90>1.75 on gloss coated paper). Using M3 polarized filter make the measurements more consistent, it always measures the ink as if it is still wet.