Problems resolution

 

INCIDENTS DURING THE PRINTING
Nature of the incident
Origin(s)
Remedy (ies)
– During the inking, the coat of gelatin come unstuck, gets loose in some parts. – Fat tracks on the glass paving stone during the operations of sprawling of the gelatin. – Degrease completely the plate with pure ammonia water before crossing the adhesive sublayer, and not touching with fingers on this first coat before putting the bichromatée coat.
– The paving stone keeps a part of its ink, instead of to put down everything on the prints.

– lack of pressure on the cylinder of the press.

– Too hard ink.

– Increase the pressure of the cylinder (regulation of the press).

– Soften the ink by adding it one girl quantity of average varnish.

– The prints are too light, no detail in the dark parts, blacks lack depth (no halftone).

– Gelatin underexposed.

-Too wet gelatin, not enough charged in ink.

– Unusable paving stone, because we cannot make come what does not exist. Begin again another sunstroke.

– Wait a little that the paving stone dries, or to cross some sheets without inking.

-The paving stone takes a lot of ink in the dark parts of the image, onbres is too much darkened and have no detail, the whites cover themselves with a grey veil.

– Too dry paving stone.

– Too much exposed gelatin.

– Too flexible ink (error during the preparation of the ink – > excess of added varnish).

– Clean the plate, and proceed to a more prolonged wetting.

– Unusable paving stone, because we cannot give her the necessary humidity. Begin again another sunstroke.

– Restore the balance by modifying the consistency of the ink. Add it some harder ink, but no varnish.

– Spots, blackheads appear on the plate and prints.

– Foreign bodies in the ink, or fallen on the plate during the printing (big dusts).

– Dusts, foreign bodies included in the coat of gelatin.

– Avoid the dust in the workshop.

– Look after the filtering of the gelatin ; remove dusts which can settle on the plate during its sprawling in the drying oven (just before closing it). They are visible in shaving light. Remove them with the fingertip.