Week 9 Paint, media and coatings

Question 1

coatings can be clear (varnish) or pigmented (paint). what is a paint?

how does oil paint bind

Answer 1

a pigment and a binding medium (wetting)

compatibility depends on surface tension and attraction

often incompatibility can be overcome with wetting agents (washing up liquid), creating an emulsion system

oil crosslinks as it combines with oxygen, holding the pigment in place.

Question 2

with pigments, what else might be visible in the cross section

Answer 2

ground, to bulk out the pigment (expense)

also a support, maybe primed, (eg calcium carbonate)

can also see cross section of canvas thread underneath paint layer

Question 3

examples of compounds used as paint pigments

Answer 3

can be synthetic or natural, salts or organic pigments

Question 4

Table showing pigments and properties

Answer 4

Question 5

how might paint set, how is this affected (4)

Answer 5

by media used

Question 6

drying process of painted surface- how does evaporation effect the material

Answer 6

(bridges- of media between the particles of pigment)

Question 7

how does pigment size effect the physical painting, and its decay

Answer 7

Question 8

what does colour saturation depend on

Answer 8

pigment particle size and refractive index of particle and media, and the finish (eg thin or thick)

Question 9

what does colour saturation depend on

Answer 9

pigment particle size and refractive index of particle and media, and the finish (eg thin or thick)

Question 10

What is the refractive index

Answer 10

different light refractions for the media and for the pigment

Question 11

how is the appearance of paint influenced by the physical properties of materials and their refraction

Answer 11

Question 12

differences between refractive index of a pigment and RI of binding media

Answer 12

Question 13

how does the refractive index effect the light and colour

Answer 13

Question 14

what are the potential functions of paint coating

Answer 14

Question 15

what is a tempera

Answer 15

aka a paint medium

Question 16

gouache- properties and materials

Answer 16

Question 17

chemical structure of gums eg gum arabic

Answer 17

made up of complex carbohydrates eg. fructose
high molecular weight

Question 18

materials and paints; chalk

Answer 18

Question 19

watercolours are a form of t_______. what are their properties

Answer 19

Question 20

examples of materials used in oil paints

Answer 20

Question 21

chemical structure of oils

Answer 21

Question 22

egg media as an example of tempera

Answer 22

drying oils; oils with unsaturated side chains, in contact with oxygen they create links, oxidise and harden

Question 23

acrylics; materials and properties

Answer 23

Question 24

analysis protein chains in paints

Answer 24

Question 25

acrylic paint- drying process (4)

Answer 25

Question 26

examples of transparent coatings and varnishes

Answer 26

Question 27

what are resins

Answer 27

terpine- good binders