Test #2 Flashcards Preview

Understanding Colour > Test #2 > Flashcards

Flashcards in Test #2 Deck (119):
1

how are light and colour related?

light is made of all of the colours of the rainbow because it contains all wavelengths

2

How are temperature and colour related?

The temperature of the object affects the color of the light that is radiated.

3

Why is Ittens colour wheel special?

It is the basis of the modern day colour wheel we currently have

4

Additive Colour mixing

The additive primary colors are red, green and blue (RGB).

5

Subtractive colour Mixing

The subtractive primary colors are cyan, magenta and yellow (CMY).

6

what is Newton’s experimentum crucis

proof that white light was composed of colored light rather that different-colored light resulted from differing speed through a medium.

7

What is Trichromacy and tricolour vision theory?

Thomas Young and Hermann von Helmholtz in the 19th century theory of color vision, there are three receptors in the retina that are responsible for the perception of color. One receptor is sensitive to the color green, another to the color blue and a third to the color red. These three colors can then be combined to form any visible color in the spectrum

8

what is the Opponent Process theory?

Opponent-process theory suggests that color perception is controlled by the activity of three opponent systems. In the theory, he postulated about three independent receptor types which all have opposing pairs: white and black, blue and yellow, and red and green.

9

What is Synaesthesia?

Synaesthesia is a neurological trait or condition that results in a joining or merging of senses that aren't normally connected. The stimulation of one sense causes an involuntary reaction in one or more of the other senses.

10

what are B/S cones for?

absorb short wave lengths

11

What are G cones for?

absorb middle wave lengths

12

What are R cones for?

absorb long wave lengths

13

Vision acuity is a term which refers to?

Visual acuity is dependent on optical and neural factors, i.e., (i) the sharpness of the retinal focus within the eye, (ii) the health and functioning of the retina, and (iii) the sensitivity of the interpretative faculty of the brain.

14

wha does the ciliary muscle do?

The ciliary muscle, which is a smooth muscle responsible for lens accommodation, is contained within the ciliary body

15

what are the 5 main causes of colour?

1. Vibrations & Excitations
2. Transitions involving Ligand Field Effects
3. Transitions involving Molecular Orbitals
4. Transitions involving Energy Bands
5. Geometrical & PhysicalOptics

16

Define Molecule

a grouping of two or more atoms together in a specific arrangement, held together by chemical bonds.

17

What is a covalent bond?

two electrons between atoms are ‘shared’ to complete their valences & achieve atomic stability.

18

define ionic Bond

It is a type of chemical bond that generates two oppositely charged ions.

19

isotope is an atom that...

an atom with different numbers of protons and neutrons. This atom has the same chemical properties of its element (i.e. element with equal number of protons and neutrons)

20

what is an ion

atom after gaining or losing electrons, leaving it unbalanced and having a +ve or –ve charge, overall.

21

what is valence

themaximumnumberofsinglebondsan atom can make – i.e. the maximum number of valence electrons the atom can lose, add, or share to form a bond with other atoms (‘bonding power’).

22

what is the aqueous humour?

The aqueous humour is a thin, transparent fluid similar to plasma. It’s made up of 99.9% water ­­– the other 0.1% consists of sugars, vitamins, proteins and other nutrients. This fluid nourishes the cornea and the lens, and gives the eye its shape.

23

what is beta-carotene

The bonds shown in red make up the chromophore of beta carotene – the part of the molecule that is responsible for its colour.

24

define Retina

a layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.

25

define chromophore

The part of a molecule that is responsible for
giving its colour, through absorption of certain visible photons.

26

define Vitreous Humour

The vitreous humour (also known simply as the vitreous) is a clear, colourless fluid that fills the space between the lens and the retina of your eye.

27

define Optic Nerve

is a paired nerve that transmits visual information from the retina to the brain.

28

define Choroid

the pigmented vascular layer of the eyeball between the retina and the sclera.

29

Porphyrins

are extensive networks of carbon rings that are joined by conjugated bonds. These are often stabilized by an element like iron or copper or manganese that also contribute to the colour.
Examples: chlorophyll (stabilized by magnesium) hemoglobin (stabilized by iron)

30

electronic energy state

interactions of electrons (forming bonds with other atoms’ electrons, absorbing/emitting light, etc)

31

vibrational energy state

tiny vibrations (movement) of molecules inside the medium

32

rotational energy state

tiny rotations (‘spinning’) of molecules on their axes of symmetry inside the medium

33

pure covalent vs polar covalent

Pure covalent are bonds between two elements with identical electronegativities. For these bonds the electrons are perfectly equally shared between the two atoms. Polar covalent bonds form between elements with different electronegativities but those that aren't large enough that we could call the bonds ionic.

34

electronic vibrational then rotational in order

hardest to easiest to change

35

which part of the molecule gives the colour?

chromophore

36

when boron and carbon make a diamond what colour is given off?

blue

37

microwaves uses what kind of energy to heat up the food?

rotational energy

38

Pigment

A material that absorbs some wavelengths and reflects other wavelengths back to our eye to give a substance a perceived colour

39

natural pigment

• mineral, plant or animal source
• modified only through grinding, washing, filtering or heating

40

synthetic pigment

• assembled (or significantly modified) during an industrial chemical process

41

organic

• molecules contain carbons with combinations of
hydrogen, nitrogen or oxygen

42

inorganic

• mineral compound with one or more metal or rare earth elements

43

synthetic organic

Synthetic organic pigments make up 80% of the world’s pigment production.
Why?
• cheaper to produce in mass scales • bigger variety of colours possible • brighter colours possible
• colours ‘stay’ longer
• colours are more resistant to fading and other ‘weathering’ effects

44

what are the six key pigment properties?

• colour appearance (molecular structure)
• particle size (total surface area)
• lightfastness (resistance to fading on exposure to light) • tinting strength (‘colour-changing’ ability)
• transparency
• specific gravity (weight of pigment in water)
‘Opacity’ is also another relevant property, that depends on the combination of size and transparency (or refractive index) of pigment particles.

45

particle size

Pigment particles are usually significantly ‘large’ in size, ranging from 50 nm to 100,000 nm

46

changing particle size (smaller)

• increased tinting strength (more intense colour)
• more transparent (more ‘empty spaces’ between pigments, i.e. of white paper) • higher staining power (smaller particles embed into paper fibres easily)
• less lightfastness (resistance to fading under exposure to (UV) light)
• lower permanence (resistance to ‘wear and tear’ from heat, water, acids and other sources)

47

Changing the size of a pigment particle can affect which quality of the material it is used to colour?
a. Weight
b. Reactivity
c. Transparency
d. Heat

Transparency

48

Lightfastness

the ability of a pigment to resist change (fading) under continued exposure to light.

49

Permanence is...

the ability of pigments to resist changes due to other additional environmental conditions such as heat, water (humidity), acidity, mould, etc.

50

Tinting strength is...

the ‘colouring power’ of a pigment: it tells us the amount of pigment required to colour a clear liquid (or white paint). The stronger the tinting strength of a pigment, the less of it is need to ‘colour’ another clear substance. It is often given as a 1:10 ratio (i.e. 1 part of pigment is needed for every 10 parts of clear substance).

51

Transparency is...

a measure of how much a single layer of pigment (paint) disappears from view, after it has been applied on a black/dark background. Or, in another view, transparency shows how much of the ‘background/surface’ layer, between the pigment particles, will be visible after the pigment/paint solution has been applied and dried on the surface.

52

opacity or ‘hiding power’:

the thickness of paint (pigment layer) needed to ‘hide’ a black-white pattern on a surface.

53

Specific gravity of pigments is...

their weight in water. It is defined as the ratio of weight of pigment amount to the weight of water sample it displaces, if placed in water.
• water has a specific gravity of 1.0
• pigments with specific gravity < 1.0 will ‘float’ in a water solution (i.e. stay suspended)
• pigments with specific gravity > 1.0 will ‘sink’ in a water solution, to the ‘bottom’ of the container

54

Sedimentary pigments are...

those that will ‘sink’ to the bottom of the solution (needs re-stirring.)

55

pigments are divided into how many types?

4,
natural organic
natural inorganic
synthetic organic
synthetic inorganic

56

Choose the best answer : which of the following is NOT a basic classification of pigment?
a. Natural synthetic
b. Synthetic organic
c. Inorganic complex
d. Natural inorganic
e. ‘a’ and ‘c’

e) a and c

57

An example of two chromophores are:
a. Haline & Thorazine
b. Beta carotene & Chlorophyll
c. Guanine & Cytosine
d. Hydrogen & Sodium
e. Chlorophyll & Psilocybin

b. Beta carotene & Chlorophyll

58

We discussed LIGHT and COLOUR in terms of ____ main properties. We discuss PIGMENTS in terms of ____ main properties.
a. 2;4
b. 1;5
c. 3;6
d. 4;5
e. 6;3

c. 3 few, 6 hsv

59

Which of the following is NOT a main property we use to discuss pigments?
a. Temperature
b. Lightfastness
c. Transparency
d. Specific Gravity
e. Colour Appearance

a. Temperature

60

organic molecules have what in them?

has hydrocarbon in it (fuels, methane, ethane, propane, butane)

61

what do inorganic molecules not have

can contain carbon but most likely not

62

Heteroatom

any atom other than C or H found in an organic compound

63

Amine

one or more organic groups (C,H) bonded to a nitrogen atom.

64

Mauveine, the first synthetic dye to be mass produced, was discovered while attempting to synthesize quinine which was used to treat:
a. Syphilis
b. Malaria
c. Polio
d. Mononucleosis
e. Influenza

b. Malaria

65

An amine is:
a. One or more organic groups joined with a sulfur atom
b. One or more organic groups joined with a carbon atom
c. Two or more organic groups joined with a hydrogen atom
d. One of more organic groups joined with a nitrogen atom
e. None of the above

d. One of more organic groups joined with a nitrogen atom

66

Amines are a derivative of this kind of molecule: a. Carbon
b. Oxygen
c. Diatomic hydrogen
d. Diatomic nitrogen
e. Ammonia

e. Ammonia

67

Leaves change colour in fall because
chlorophyll production lessens due to:
a. Increased precipitation
b. Decreased temperatures
c. Decreased sunlight
d. Increased sunlight
e. ‘a’ and ‘c’

c. Decreased sunlight

68

chlorophyll is pigment ( a porphryn) that: –

absorbs red and blue wavelengths
– reflects green wavelengths

69

Ammonia

-produced as waste product of microorganisms
• Acts as a plant nutrient, used in fertilizers (and explosives)
• Ammonia is important in the atmosphere in terms of temperature stability with height, precipitation distribution, haze, the nitrogen cycle and being a source of cloud condensation nuclei

70

Dyes consist of 2 main parts what are they

Chromophore:
Gives colour
N2
NO, NO2 C=O
C=S

Auxochrome
Augments colour, Binds colour to fabric
OH O-C=OH

71

what is the Industrial revolution by product

Coal tar:
• Trying to synthesize quinine (to cure malaria)discovery of
mauvine
• Germany led applied Chemistry industry (eg. companies such as Bayer, BASF)
• Indigo synthesized, Azo dyes produced

72

Germany chemistry and associated colour science leads to...


• Colour indicatorspH testing, safety, disease treatment
• Targetting pathogens by colour  “magic bullet”  chemotherapy
• Chemical Warfare (Chlorine gas)

73

William Henry Perkin, Chemist 1838 - 1907

• Discovered Mauveine, 1856, age 18
• Accidental discovery while trying to
synthesize quinine to cure Malaria
• After discovery, quit school to start chemical dye factory
• Kick started the synthetic dye industry
• Mauveine remains very popular today
• The Perkin medal is the highest honour in industrial chemistry, given by the Society for Chemical Industry annually for "innovation in applied chemistry resulting in outstanding commercial development."

74

Friedrich Bayer with Johann Friedrich Westkott in 1863 founded the company which would become the chemical and pharmaceutical giant, “Bayer”

• known for aspirin, among other things
• Many factories in the WuppertalWupper Valley (German early industry center)

75

Fritz Haber, Chemist 1868 - 1934

• Discoverer of the “Haber Process”
• Haber Process: uses atmospheric nitrogen
(N2) for ammonia (NH4) production
• Important fertilizer: responsible for most of the world’s food & increased crop yields
• Seen as ‘father of chemical warfare’
• WWI: developed Chlorine gas
• 1st wife, Clara, was the first woman in Germany to get a PhD in chemistry

76

Azo dyes

(contained in 68% of colorants)
Prohibited in European food products in 2003

77

Chlorophyll

• there is one key ring in the chlorophyll that causes the colour, in this ring is a magnesium ion that is key in producing the colour.
• This ring, the molecule’s chromophore, is called a chlorin.
• The chlorin is key to photosynthesis since this is where light is first absorbed and eventually (through a long chemical process) ends up being stored as glucose.
Chlorophyll Cont’d.
• Thereareseveraldifferenttypesofchlorophyll molecules
• eachtypeabsorbslightataslightlydifferent wavelength due to differences in overall chemical structure
• role of chlorophyll is to absorb sunlight and drive photosynthesis reactions which provide energy (food) for plant

78

• Tetrapyrrole

group of 4 pyrrole or pyrrole-like rings. Pyrrole  bond of form =CH or -CH

79

A leaf is more likely to turn red if:
a. Sugar content is lower
b. Sugar content is higher
c. Chlorophyll content is higher
d. Beta carotene content is higher
e. Chlorophyll content is lower

b. Sugar content is higher

80

Anthocyanins

• Formedbyreactionsbetweensugars+certain proteins in cell sap
→ does not occur until sugar concentration high
→ requires sunlight
• topsoftrees,sidefacingsouth→turn red first
NOTE: carotenes are already present in the leaf whereas anthocyanins do not form until after the chlorophyll has broken down

81

carotenes vs chlorophyll

carotenes are already present in the leaf whereas anthocyanins do not form until after the chlorophyll has broken down

82

• Flavones

- yellow

83

• Tannins

– brown

84

Variegated leaves

• This occurs when there is variation in colour across the surface of a leaf
• Variegated plant leaves can arise for different reasons.

85

Chimeral Variegation

- This is a genetic condition.
• certain areas of the leaf and /or stems lose the ability to produce chlorophyll ,resulting in a white or yellowish colouration.

86

causes of colour change in leaves

• Diseases
• Nutrient deficiencies
• Excessive sunlight

87

A pigment’s transparency refers to:
a. How see-through the pigment is
b. The fineness of pigment particles
c. How much white shows through the colour
d. Viscosity of the pigment + binder
e. The refractive index of pigment particles

c. How much white shows through the colour

88

On a molecular level, the following are two key components of a dye:
a. Finasteride, chromasync
b. Phytol, glycerin
c. Chromophore, auxochrome
d. Pigment, stearate
e. Choloroform, achlora

c. Chromophore, auxochrome

89

Dye

an unstable chemical compound, typically having a key central ‘ring’ of conjugated Carbon bonds (with other elements), where electrons in these bonds are ‘more free’ to move/absorb incoming light, depending on the specific chromophore included in the molecular structure.
Typically, dyes have the colourless Benzene (C6H6) molecule as their ‘main foundation’:
The actual colour of the dye results from having a different ‘substitution group’ (called aryl group) attached to one (or more) of the carbon atoms in the ring, making up the chromophore part of the molecule:

90

Dyes vs. Pigments

There are two important distinctions between pigments and dyes: their solubility and affinity characteristics.
Solubility: how well a substance dissolves in a solution.
• Pigments are not soluble (they stay ‘suspended’ in a binder)
• Dyes *are* soluble
Affinity: how well a substance will form bonds with the physical surface onto which it is being applied (called ‘substrate’).
• Pigments have little to no affinity to the surface (they stay ‘on top’ of the surface)
• Dyes generally have a strong affinity to the surfaces they’re being applied to (they will form permanent chemical bonds with the surface); sometimes they may need a ‘mordant’ to make the dye ‘stick faster’.

91

Dyes vs. Pigments

Solubility: how well a substance dissolves in a solution.
• Pigments are not soluble (they stay ‘suspended’ in a binder)
• Dyes *are* soluble
Affinity: how well a substance will form bonds with the physical surface onto which it is being applied (called ‘substrate’).
• Pigments have little to no affinity to the surface (they stay ‘on top’ of the surface)
• Dyes generally have a strong affinity to the surfaces they’re being applied to (they will form permanent chemical bonds with the surface); sometimes they may need a ‘mordant’ to make the dye ‘stick faster’.

92

LAKE pigments

• pigments that have originated as a dye (often azo dye), but a fixing agent (mordant of metallic salt) has been added to change them.
• the colour agent is usually precipitated out of solution
• these type of pigments can often be unstable (they fade
or otherwise change) when exposed to light
• these unstable pigments are sometimes referred to as fugitive

93

Indicators

• Indicators are dyes which are weak acids that will have one colour in acid form and a different one in (conjugated) base form.
• The colour changes as a proton is accepted or donated.
• Losing or gaining the proton changes the structure of the molecule in a way that affects the colour

94

White, or yellow grape juice is ____ acidic than / as red grape juice.
a. more
b. less
c. equally

b. less

95

An indicator ______ to show how acidic or basic a solution is
a. Explodes
b. Changes colour
c. Changes consistency
d. Changes state
e. Turns red

b. Changes colour

96

As chemical compounds, generally all dyes are inherently:
a. Stable
b. Unstable
c. Radioactive
d. Synthetic
e. Organic

b. Unstable

97

Dye

An unstable chemical compound, typically having a key central ‘ring’ of conjugated Carbon bonds (with other elements), where electrons in these bonds are ‘more free’ to move/absorb incoming light, depending on the specific chromophore included in the molecular structure.
Typically, dyes have the colourless Benzene (C6H6) molecule as their ‘main foundation’:
The actual colour of the dye results from having a different ‘substitution group’ (called aryl group) attached to one (or more) of the carbon atoms in the ring, making up the chromophore part of the molecule:

98

In a(n) _______, the more ______ bonds there are, the more red the leaf appears.
a. anthocyanin, double
b. anthocyanin, single
c. Chromophore, triple
d. Carotenoid, single
e. Carotenoid, double

e. Carotenoid, double

99

A lake is:
a. A pigment that started off as a dye but is changed by adding a mordant
b. A pigment that is titrated and subsequently heated under high pressure
c. A solvent used with a binder
d. A natural organic dye

b. A pigment that is titrated and subsequently heated under high pressure

100

Direct dyes:

form (sometimes weak) chemical bonds with fabric

101

Dispersed dye:

if colorant not soluble in water, it can suspend in soap and apply to fabric-pigment particles. Directly attaches to fabric  better for dyeing polyesters

102

Fibre reactive dyes

: a few dyes can react chemically to form permanent bond (covalent)

103

Vat dyes

: colour formed right in fibre colour does not appear unless given proper treatment, eg. indigo, Tyrian purple not formed until dye is exposed to air & sunlight

104

What is Alchemy?
a. a psychological doctrine
b. a colour description system
c. the quest to transmute metals & find a universal elixir
d. necromancy
e. a black art

c. the quest to transmute metals & find a universal elixir

105

Paint:

a colour mixture (colloid) used to give colour to or change the colour of a surface.

106

Colloid:

mixture in which the particles do not dissolve but are small enough not to sink.

107

• Additives:

to assist / control different paint properties like particle size, withstanding weather, drying time, etc.

108

• Extenders:

larger pigment particles improve adhesion, preserve binder

109

In this course so far, we mentioned ____ different types of paints.
a. 4
b. 6
c. 5
d. 2
e. 3

c. 5

110

Which of the following is NOT one of the three main constituents of paint?
a. A pigment
b. A mordant
c. A binding medium
d. A solvent

b. A mordant

111

When we talk about “the vehicle” of a paint, we are referring to these 2 key constituents:
a. The pigment & solvent
b. The pigment & binding medium
c. The binding medium & solvent
d. The extender and binding medium
e. The volatiles and extenders

c. The binding medium & solvent

112

Float glass

: a sheet (flat piece) of glass made by molten glass solidifying on molten metal

113

Aluminum mirror

: float glass sputtered with aluminum powder (powder evaporates on the glass) in a vacuum chamber.

114

• Fluorescence

: Substance or organism absorbs UV light and re-emits it in dark conditions as VISIBLE light.

115

• Luminescence:

Substance or organism PRODUCES its own light.
Fluorescein Dye in water with UV light

116

A ______ is a cross sectional piece of a ________.
a. Cane; murrina
b. Murrina, cane
c. Rod, cane
d. Murrina, rod
e. Granule; murrine

b. Murrina, cane

117

Float glass is made by:
a. Depositing molten glass on molten metal
b. Cooling molten glass in water
c. Combining sulfite grounds with calcium carbonate
d. Coating liquified glass with aluminum
e. Pressing resin under high heat

a. Depositing molten glass on molten metal

118

• GFP

or “Green Fluorescent Protein” from jellyfish has commonly been used to make other animals fluoresce under UV light (eg. fish, cats)

119

Congenital disorder

complete or partial lack of melanin pigments in hair, eyes, skin.