GMI Ink & Substrate Interaction

Question 1

Which substrate property most directly affects the rate at which ink is absorbed after printing?

Accepted Answer

Porosity

Answer

Surface energy

Answer

Basis weight

Answer

Caliper thickness

Question 2

In the context of offset lithography, what does 'ink tack' refer to?

Accepted Answer

The resistance of ink to splitting between surfaces

Answer

The viscosity of the ink at rest

Answer

The adhesion strength between ink and substrate after drying

Answer

The pigment concentration in the ink formulation

Question 3

What phenomenon occurs when ink laid down in a later printing unit fails to adhere properly to ink already printed by an earlier unit?

Accepted Answer

Poor ink trapping

Answer

Ink strike-through

Answer

Dot bridging

Answer

Ink emulsification

Question 4

Coated papers generally produce smaller printed dot sizes compared to uncoated papers because:

Accepted Answer

The coating layer reduces ink absorption and lateral spread

Answer

Coated papers have higher caliper, restricting dot spread

Answer

Coated papers have lower surface energy repelling the ink

Answer

The clay coating chemically reacts with ink pigments to fix them faster

Question 5

Surface energy of a substrate is measured in which units?

Accepted Answer

Dynes per centimeter (dyn/cm)

Answer

Newtons per meter squared (N/m²)

Answer

Pascals (Pa)

Answer

Grams per square meter (g/m²)

Question 6

Which of the following best describes the term 'ink dry-back' in print production?

Accepted Answer

The apparent density reduction that occurs as ink dries and loses gloss

Answer

The reversible softening of dried ink when rewetted

Answer

The migration of ink pigment from substrate to substrate in a stack

Answer

The curling of substrate caused by ink solvent evaporation

Question 7

In offset printing, 'picking' is a defect most directly caused by:

Accepted Answer

Excessive ink viscosity combined with high ink tack pulling substrate fibers or coating off the surface

Answer

Too little dampening solution causing ink to deposit unevenly

Answer

Substrate porosity exceeding the ink's penetration rate

Answer

Ink pigment settling in the ink fountain over time