Ink & Substrate Interaction Flashcards
7 cards from real GMI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Ink & Substrate Interaction flashcards as text
Which substrate property most directly affects the rate at which ink is absorbed after printing?
Answer: Porosity
Porosity determines how quickly and deeply ink penetrates a substrate's fiber structure, directly controlling absorption rate.
In the context of offset lithography, what does 'ink tack' refer to?
Answer: The resistance of ink to splitting between surfaces
Ink tack is the resistance to splitting that occurs when the ink film is pulled apart between the plate, blanket, and substrate surfaces.
What phenomenon occurs when ink laid down in a later printing unit fails to adhere properly to ink already printed by an earlier unit?
Answer: Poor ink trapping
Poor ink trapping happens when a subsequent ink color does not properly adhere to a previously printed ink layer, causing color shifts and density loss.
Coated papers generally produce smaller printed dot sizes compared to uncoated papers because:
Answer: The coating layer reduces ink absorption and lateral spread
The smooth, non-porous coating layer prevents ink from spreading laterally into the substrate, resulting in sharper, more controlled dot reproduction.
Surface energy of a substrate is measured in which units?
Answer: Dynes per centimeter (dyn/cm)
Surface energy is measured in dynes per centimeter (dyn/cm), indicating the substrate's ability to be wetted by inks and coatings.
Which of the following best describes the term 'ink dry-back' in print production?
Answer: The apparent density reduction that occurs as ink dries and loses gloss
Ink dry-back refers to the decrease in apparent optical density and gloss that occurs after ink initially sets and fully dries, which must be compensated for during color management.
In offset printing, 'picking' is a defect most directly caused by:
Answer: Excessive ink viscosity combined with high ink tack pulling substrate fibers or coating off the surface
Picking occurs when the ink film's tack force exceeds the surface strength of the substrate, tearing away fibers or coating particles from the paper surface.