Digital BW, The Print

...as to Photo Flo, I'm always surprised when anybody has used it at
more than 3 drops per 500cc...that's been recommended forever. 


...as to glycerine...it will inherently evaporate completely. 

If it's required to adhere pigment to glossy paper, or if it's
required for gloss component of pigment, it will be a problem. 

If its serving a purpose other than short-term lubrication, it'll
actively be some sort of problem.