Blinding

 

Wetting agents and or surfactants deposit on to plates that will coat or adhere too the image area becoming non ink receptive.

Gum blinding is created when too much gum is deposited onto plate in sufficient amount to adhere too the image area of plate becoming non ink receptive.

CAUSE CURE
Excessive pressure causing premature plate wear. Check ink forms and plate to blanket pressures, adjust too recommended settings.
Ink and dampening roller improperly set. Reset too press manufacturer specs. Check roller durometer for hardness. Replace as necessary.
pH too low. Check pH and conductivity and reset pH to manufacturer’s specs.
Too much gum in mixed solution. Re-etch plate and rub ink in image area. Drain F/S tank and refill with R.O. or tap water. If image returns, drain water and replace with mixed F/S containing less gum.
Plate cleaners or scratch removers dried in the plate image areas. Rinse thoroughly with water to remove dried material.
Cleaning detergents or B&R wash contamination. Make sure all parts that come into contact with press are rinsed thoroughly before installation. Wash roller train and dampening to remove any contamination.
Plate not imaged or developed properly. Review your plate making procedures. Check developers and finishing processors. Also check into pre and post bake procedures.
Too much wetting or surfactants in mixed solution. Readjust to correct dosage. If problem persist contact Fountain Solution manufacturer to recommend correct solution. If surfactants are originating from B&R washes discontinue use.
Paper fillers depositing in image areas of plate. Increase lubrication thru fountain solution or ink.
Incorrect ink formulation. Consult with ink manufacturer.
Hollow or vanishing dot in image areas. Tricky solution, CTP and Stochastic is a software solution. Ink varnishing and or lint build up in the surrounding areas can be controlled through increased lubrication.