What effect do gloss enhancers have on prints?

[Some Guy]

I'm curious as to the general consensus as what the HP gloss optimizer coating, or a secondary gloss coating or lacquer, has on prints?  I know it was designed for bronzing so I'll keep it out of this discussion for now.

Does the gloss stuff darken or lighten shadows?  Lighten or darken highlights?  Etc.

Seems, to my eyes, it seems darken shadows more than anything.  Whatever gloss it has might make a bit more sheen or sparkle in the the highlights.

Is this measurable on a spectrometer, or just a visual/subjective appearance?

SG

[Geraldo Garcia]

It does not "enhance" or do anything to the already glossy areas. It mostly minimizes gloss differential and bronzing, that can be pretty bad without it on semi-gloss/satin papers. Gloss differential is the main problem of pigmented prints today, IMO. As the liquid is not absolutely transparent it surely darkens things a very little bit, but nothing that a good profile (and the usual sofproofing and corrections of the print workflow) would not correct.