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PAU Graphic-Plastic Expression Techniques (UIB) study materials
PAU Graphic-Plastic Expression Techniques (UIB) study resources

PAU Graphic-Plastic Expression Techniques (UIB) practice questions

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Question 1Graphic-plastic expression: materials, image-making and project evidence

What is the key difference between vine charcoal and compressed charcoal?

  1. Vine charcoal consists of charred willow or vine twigs without added binders, making it soft and easily erasable Correct answer.
  2. Vine charcoal is bound with gum arabic, making it insoluble in water
  3. Compressed charcoal contains no binders and cannot produce dark tones
  4. Compressed charcoal is made from burnt animal bones and leaves permanent oil stains

Explanation

Vine charcoal (carboncillo natural) is produced by burning willow or vine twigs in oxygen-deprived kilns without any added binding agents. This makes it soft, easily smudged, and simple to erase. In contrast, compressed charcoal uses a binder (like gum or clay) to yield denser, darker lines that are harder to erase.

Question 2Graphic-plastic expression: materials, image-making and project evidence

On the graphite pencil hardness scale (H to B), what does a high 'B' rating signify?

  1. Higher proportion of clay binder, resulting in a harder pencil that makes fine light lines
  2. Higher graphite-to-clay ratio, yielding a softer core that deposits darker, richer black lines Correct answer.
  3. Addition of polymer wax, making the lead waterproof and unerasable
  4. Increased core diameter designed exclusively for technical architectural drafting

Explanation

The 'B' stands for Blackness. A higher number before B (e.g., 6B or 8B) indicates a higher proportion of graphite relative to clay binder, resulting in a softer pencil lead that leaves darker, broader, and more smudgeable marks.

Question 3Graphic-plastic expression: materials, image-making and project evidence

Traditional Indian ink (tinta china) achieves waterproofness when dry primarily due to which component?

  1. Linseed oil emulsion mixed into water
  2. Sodium silicate acting as a crystalline catalyst
  3. Shellac (goma laca) or acrylic resin acting as a binder Correct answer.
  4. Gum tragacanth dissolved in ethanol

Explanation

Traditional Indian ink combines fine carbon black pigment with a binder such as shellac (goma laca) dissolved in a mild alkaline solution. Once dry, shellac forms a water-insoluble film, making the ink waterproof and ideal for watercolor washes applied over dried ink lines.

Question 4Graphic-plastic expression: materials, image-making and project evidence

How do oil pastels differ chemically and mechanically from soft pastels (pastel seco)?

  1. Oil pastels use water-soluble gum arabic, whereas soft pastels use linseed oil
  2. Soft pastels contain synthetic plasticizers that cure into an insoluble plastic film
  3. Oil pastels require aerosol fixatives immediately to prevent pigment evaporation
  4. Oil pastels use a non-drying mineral oil and wax binder, preventing them from hardening or powdering Correct answer.

Explanation

Oil pastels consist of pigment bound with non-drying mineral oils and wax. Because the oil does not dry or oxidize like linseed oil, oil pastels remain workable, soft, and un-powdered indefinitely, whereas soft pastels use minimal water-soluble binders (like gum tragacanth) and produce dry, dusty marks.

Question 5Graphic-plastic expression: materials, image-making and project evidence

In paper specification, what does the measurement unit 'g/m²' (grammage) indicate?

  1. The weight in grams of one square meter of the paper, reflecting its thickness and mass Correct answer.
  2. The grain roughness index of the paper surface
  3. The proportion of rag cotton content relative to wood pulp
  4. The light absorption percentage of archival watercolor paper

Explanation

Grammage measured in g/m² (grams per square meter) specifies the weight of paper. Heavier papers (e.g., 300 g/m²) are thicker and resist warping or buckling when exposed to wet media like watercolor or ink washes.

Question 6Graphic-plastic expression: materials, image-making and project evidence

Which paper surface manufacturing finish is pressed between heated iron rollers, creating a smooth, toothless surface ideal for fine pen-and-ink detail?

  1. Rough (torcheón)
  2. Hot pressed (satiné / satinado) Correct answer.
  3. Cold pressed (NOT / fin)
  4. Deckle edged (barbas)

Explanation

Hot pressed paper (papel satinado) is passed through heated metal rollers during manufacturing. This flattens the paper fibers to create a dense, smooth surface without tooth, making it preferred for botanical illustration, technical ink drawing, and fine detail work.

Question 7Graphic-plastic expression: materials, image-making and project evidence

Sanguine (sanguina) is a classical drawing medium characterized by its distinct reddish-brown earth tone. Which mineral pigment gives sanguine its characteristic color?

  1. Cupric carbonate (malachite)
  2. Manganese dioxide
  3. Anhydrous or hydrated iron oxide (hematite) Correct answer.
  4. Calcined bone charcoal

Explanation

Sanguine derives its warm brick-red color from iron oxide (hematite). Popularized during the Renaissance by masters like Leonardo da Vinci and Michelangelo, it is frequently combined with black chalk and white highlights in the 'trois crayons' technique.

Question 8Graphic-plastic expression: materials, image-making and project evidence

What optical change frequently occurs when a resin-based spray fixative is heavily applied to a soft pastel or charcoal drawing?

  1. The tones lighten significantly due to light scattering by resin particles
  2. The paper turns bright yellow immediately from chemical reduction
  3. The pigment particles dissolve completely and turn into transparent oil
  4. The drawing darkens and loses delicate light values as resin fills air voids between pigment particles Correct answer.

Explanation

Spray fixatives bind loose dust by coating pigment particles with resin dissolved in solvent. Over-application fills the microscopic air gaps between loose pigment granules, altering how light refracts and causing the drawing to darken significantly and lose delicate tonal subtleties.

Question 9Graphic-plastic expression: materials, image-making and project evidence

How does a traditional flexible steel dip pen nib create line width variation compared to a technical pen (rápido)?

  1. By flexing its split tines apart under downward pressure, allowing more ink to flow Correct answer.
  2. By varying the angle of ink flow through an internal rotary piston valve
  3. By altering the chemical temperature of the ink stored inside the barrel reservoir
  4. By utilizing a porous felt tip that expands when compressed against paper

Explanation

A steel dip pen nib features a central split (tines). Applying downward pressure forces the tines apart, widening the ink channel and creating a line that expands smoothly from thin to thick based on artist pressure. Technical pens use a tubular point with a wire weight, keeping line width strictly constant.

Question 10Graphic-plastic expression: materials, image-making and project evidence

What advantage do alcohol-based graphic markers offer over water-based markers for professional illustration?

  1. They are completely lightfast and never fade when exposed to direct sunlight
  2. They dry rapidly and allow smooth color blending and layering without tearing or saturating paper fibers Correct answer.
  3. They can be erased cleanly with a standard kneaded eraser
  4. They dissolve wood pulp fibers to create an embossed 3D texture

Explanation

Alcohol-based markers dry quickly because the solvent evaporates rapidly. This allows illustrators to layer and blend colors smoothly without re-wetting and weakening the paper fibers, unlike water-based markers which can cause paper cockling and fiber tearing (pilling).

Question 11Graphic-plastic expression: materials, image-making and project evidence

Why does metalpoint (e.g., silverpoint) require a specially prepared ground (gesso or bone ash) on the paper substrate?

  1. Metal points require a soft wax coating to dissolve the metal wire tip
  2. The ground contains acid that turns silver into liquid ink upon contact
  3. Raw paper is too smooth, whereas an abrasive ground shears off microscopic particles of metal from the stylus Correct answer.
  4. Silverpoint requires a waterproof silicone shield to prevent ink from spreading

Explanation

Silverpoint stylus tools do not leave marks on raw paper because silver is too hard. A ground prepared with fine abrasive mineral powders (like zinc white, bone ash, or chalk mixed with hide glue) creates a toothy surface that shaves off tiny metal particles, which oxidise over time to form soft grey-brown lines.

Question 12Graphic-plastic expression: materials, image-making and project evidence

Conté crayons, invented by Nicolas-Jacques Conté in 1795, were originally developed as a substitute for pure graphite due to wartime shortages. What is their main composition?

  1. Purified beeswax, tallow, and aniline dye
  2. Calcined gypsum and linseed oil
  3. Synthetic acrylic binder mixed with powdered glass
  4. Finely ground graphite or pigment mixed with kaolin clay and a small wax/binder matrix Correct answer.

Explanation

Nicolas-Jacques Conté invented Conté crayons by compressing finely ground graphite or natural pigments (sanguine, sepia, black) with kaolin clay and a small amount of binder. They are firmer than soft pastels but produce richer, darker lines than standard graphite pencils.

Question 13Graphic-plastic expression: materials, image-making and project evidence

What is the primary function of sizing (colado) applied to watercolor and graphic papers during manufacturing?

  1. To control absorbency, preventing liquid ink and paint from bleeding instantly into paper fibers like blotting paper Correct answer.
  2. To impart a glossy reflective sheen to the finished artwork
  3. To bleach yellow wood pulp to a bright neutral white color
  4. To make the paper completely fireproof and heat resistant

Explanation

Sizing (using gelatin, starch, or synthetic agents like AKD) seals the porous spaces between cellulose fibers. Proper sizing controls absorbency so that washes of watercolor or ink stay on the paper surface long enough to be manipulated, rather than soaking in immediately.

Question 14Graphic-plastic expression: materials, image-making and project evidence

Archival museum paper is designated as 'acid-free' (papel libre de ácido). Why is acid content dangerous for graphic artwork?

  1. Acid causes paper fibers to expand uncontrollably, doubling paper thickness
  2. Acid breaks down cellulose polymer chains, causing paper to yellow, become brittle, and deteriorate Correct answer.
  3. Acid neutralizes graphite lines, making pencil drawings disappear overnight
  4. Acid repels oil paint, causing oil layers to flake off instantly

Explanation

Acid (present in unrefined wood pulp containing lignin, or introduced via alum-rosin sizing) hydrolyzes cellulose molecules. This causes acid hydrolysis, which turns paper yellow/brown and makes it extremely brittle over time, eventually leading to crumbling.

Question 15Graphic-plastic expression: materials, image-making and project evidence

What tool consists of tightly rolled paper wound into a pointed stub used by artists to blend charcoal, graphite, or pastel tones?

  1. Stylus
  2. Brayer
  3. Tortillon (difumino) Correct answer.
  4. Burnisher

Explanation

A tortillon (or paper stump / difumino) is a tightly rolled cylinder of paper with tapered ends. It is used to smudged and blend dry media (charcoal, graphite, pastel) cleanly without transferring oils from human fingers onto the paper.

Question 16Graphic-plastic expression: materials, image-making and project evidence

Which eraser type can be reshaped by hand, leaves no eraser crumbs (virutas), and lifts graphite or charcoal subtractively without damaging paper fibers?

  1. Abrasive ink eraser (goma de tinta)
  2. Vinyl plastic eraser
  3. Hard vulcanized rubber eraser
  4. Kneaded eraser (goma moldeable / moltopic) Correct answer.

Explanation

A kneaded eraser (goma moldeable) is a pliable, putty-like rubber tool. It absorbs loose graphite and charcoal particles when pressed onto paper, leaves no rolled residues or crumbs, and can be shaped into fine points for subtractive highlight creation.

Question 17Graphic-plastic expression: materials, image-making and project evidence

What is 'Ingres paper' primarily known for in graphic arts?

  1. Its distinct grid of fine laid lines (verjuras) and tooth, ideal for charcoal, pastel, and sanguine drawings Correct answer.
  2. Its heavy 600 g/m² weight designed for impasto oil painting
  3. Its synthetic plastic film surface that repels all dry media
  4. Its glossy mirror finish used exclusively for copperplate engraving

Explanation

Ingres paper is a traditional mold-made laid paper featuring fine chain and laid lines (verjurado). Its surface tooth catches loose dry particles of charcoal, sanguine, and pastel, making it a classic choice for figure drawing and portraiture.

Question 18Graphic-plastic expression: materials, image-making and project evidence

How does a reed pen (cálamo) differ in mark-making from a bird quill pen (pluma de ave)?

  1. Reed pens hold fluid ink inside a spring-loaded metal cartridge
  2. Reed pens produce rigid, angular, bold strokes with rapid ink discharge, whereas quills offer greater flexibility and fine fluid flourishes Correct answer.
  3. Quill pens can only draw on damp animal vellum and destroy paper fibers
  4. Reed pens produce soft pastel-like smudges with no distinct line work

Explanation

Reed pens cut from hollow reeds produce firm, bold, slightly broad and angular lines because of their rigid woody stem structure. Bird quills (hollow feather shafts from geese or swans) are springy and flexible, yielding expressive line variation and delicate calligraphic flourishes.

Question 19Graphic-plastic expression: materials, image-making and project evidence

In ink wash painting (aguada de tinta), how are light values and subtle gray tones created?

  1. By adding titanium white gouache paint to thicken the ink mixture
  2. By scrubbing the dry ink surface with steel wool to thin the black pigment layer
  3. By diluting the ink with varying proportions of water, letting the white paper substrate shine through transparently Correct answer.
  4. By applying a yellow shellac varnish over solid black ink lines

Explanation

Ink wash technique relies on subtractive paper reflection. Tonal range from pale silver-gray to jet black is achieved purely by diluting liquid ink with water. The transparent washes allow the white paper underneath to provide the light value.

Question 20Graphic-plastic expression: materials, image-making and project evidence

Why are traditional dye-based graphic markers generally unsuitable for fine art destined for long-term exhibition?

  1. Dye molecules dissolve paper cellulose within weeks
  2. Dye-based inks dry so slowly that they bleed across paper for months
  3. Dyes react with glass frames to produce toxic chlorine gas
  4. Dyes are organic colorants dissolved in solvent that degrade rapidly under ultraviolet light, causing severe fading Correct answer.

Explanation

Dyes consist of individual soluble color molecules rather than solid microscopic mineral particles (pigments). Dyes have poor lightfastness (baja solidez a la luz) and break down under UV light exposure, fading significantly compared to pigment-based fine art media.

Question 21Graphic-plastic expression: materials, image-making and project evidence

What is the recommended practice when applying spray fixative to a delicate charcoal or pastel drawing?

  1. Spray multiple light mist coats from a distance of 25–30 cm in a well-ventilated area, keeping the work vertical or inclined Correct answer.
  2. Hold the aerosol can 5 cm away and saturate the paper until wet
  3. Apply the spray with a stiff bristle brush directly onto paper
  4. Heat the paper with a torch while spraying to melt the resin instantly

Explanation

Fixatives should be sprayed in light, even mist layers from 25–30 cm away to prevent liquid drops from pooling or blowing loose dust off the paper. Spraying must take place in a well-ventilated space to avoid inhaling toxic solvent vapors.

Question 22Graphic-plastic expression: materials, image-making and project evidence

What is the historical difference between parchment (pergamino) and vellum (vitela)?

  1. Parchment is made from woven silk threads, while vellum is made from Papyrus reeds
  2. Parchment is made from prepared sheepskin or goatskin, whereas vellum refers specifically to fine calfskin Correct answer.
  3. Parchment is synthetic plastic, while vellum is 100% wood pulp
  4. Parchment is water-soluble gel, while vellum is hardened tree bark

Explanation

Both are animal skin substrates processed by scraping, liming, and stretching under tension (not tanned like leather). Historically, parchment was prepared from sheepskin or goatskin, while vellum designated high-grade calfskin (vitela) known for its smooth texture.

Question 23Graphic-plastic expression: materials, image-making and project evidence

How is subtractive drawing (dibujo sustractivo / al borrado) executed when using graphite or charcoal?

  1. By painting over dark areas with white oil paint
  2. By dipping graphite into acid to burn away paper layers
  3. By covering a surface uniformly with dark medium and using erasers to carve out light shapes and highlights Correct answer.
  4. By printing negative images onto glass plates using photomechanical transfer

Explanation

Subtractive drawing involves applying a continuous tone of charcoal or graphite over a substrate, then selectively removing the medium with kneaded or vinyl erasers to reveal white paper areas as highlights and mid-tones.

Question 24Graphic-plastic expression: materials, image-making and project evidence

In colored pencil drawing, what does the technique of 'burnishing' (bruñido) achieve?

  1. It removes all colored wax from paper using sandpaper
  2. It wets the colored pencil lead with water to turn it into liquid ink
  3. It oxidizes pigment particles using an electric heating iron
  4. It applies heavy pressure with a light colored or colorless blender pencil to fuse wax layers into a smooth, glossy, painterly finish Correct answer.

Explanation

Burnishing involves applying heavy pressure with a firm colorless blender pencil or light pencil over multiple layered colors. This flattens paper tooth and compresses wax/oil binder layers together, creating a unified, dense, glass-like finish.

Question 25Graphic-plastic expression: materials, image-making and project evidence

Why is natural vine charcoal easier to erase than compressed charcoal stick?

  1. Vine charcoal contains no binding additives to lock carbon dust into paper fibers Correct answer.
  2. Vine charcoal contains heavy animal grease that floats off paper
  3. Vine charcoal is made of magnetic particles repelled by rubber
  4. Vine charcoal turns into water vapor when touched by an eraser

Explanation

Natural vine charcoal is produced purely by carbonizing plant stems without binders. Because there is no binder sticking carbon to the paper, the carbon dust sits loosely on top of the paper fibers and easily wipes away with an eraser or cloth.

Question 26Graphic-plastic expression: materials, image-making and project evidence

What is the principal natural binder used in traditional watercolor (acuarela) paints?

  1. Linseed oil (aceite de lino)
  2. Gum arabic (goma arábiga) Correct answer.
  3. Egg yolk (yema de huevo)
  4. Acrylic polymer emulsion

Explanation

Gum arabic (goma arábiga), derived from the sap of Acacia trees, is the classic water-soluble binder in transparent watercolors. It holds pigment particles in suspension and re-dissolves readily when re-wetted with water.

Question 27Graphic-plastic expression: materials, image-making and project evidence

Which characteristic effect defines the 'wet-on-wet' (húmedo sobre húmedo) watercolor painting technique?

  1. Sharp, hard, hard-edged geometric brush marks
  2. Thick impasto knife textures retaining high ridges
  3. Soft, feathery color diffusion and bleeding across pre-dampened paper surfaces Correct answer.
  4. Opaque matte chalky coverage concealing underlying layers

Explanation

In wet-on-wet technique, wet paint is applied onto paper that is already damp with clean water or another wet wash. Capillary action causes the pigment to bloom, diffuse, and bleed outward, creating soft edges and subtle atmospheric gradients.

Question 28Graphic-plastic expression: materials, image-making and project evidence

How does gouache (guache / témpera) differ structurally from transparent watercolor?

  1. Gouache uses linseed oil instead of water as a vehicle
  2. Gouache cannot be re-wetted once dry
  3. Gouache requires heat curing in an oven to harden
  4. Gouache contains opaque white extenders (like chalk/barium sulfate) or higher pigment loads, making it opaque and matte Correct answer.

Explanation

Gouache is an opaque watercolor. It uses the same gum arabic binder as watercolor but incorporates inert white pigments (chalk, precipitated calcium carbonate, or blanc fixe) and higher pigment concentrations, making its paint layers opaque with a velvet-matte finish.

Question 29Graphic-plastic expression: materials, image-making and project evidence

What chemical transition occurs when acrylic paint dries?

  1. Evaporation of water causes acrylic polymer particles to coalesce into a flexible, water-insoluble resin film Correct answer.
  2. Oxidation of vegetable oils creates a brittle crystalline crust
  3. Evaporation of turpentine leaves behind solid tree resin powder
  4. Chemical reaction with carbon dioxide turns the paint into calcium carbonate

Explanation

Acrylic paint consists of pigment suspended in an acrylic polymer emulsion with water. As water evaporates, the microscopic acrylic resin spheres press together and coalesce into a durable, flexible, plastic film that can no longer be dissolved by water.

Question 30Graphic-plastic expression: materials, image-making and project evidence

Why is it scientifically inaccurate to say that oil paint 'dries' by evaporation?

  1. Oil paint dries purely through subterranean freezing of solvents
  2. Oil paint solidifies through oxypolymerization (absorption of oxygen and cross-linking of fatty acid chains) Correct answer.
  3. Oil paint absorbs nitrogen gas to liquefy permanently
  4. Oil paint hardens when exposed to radio waves

Explanation

Drying oils (like linseed, walnut, or safflower oil) do not contain volatile water or solvents that evaporate. Instead, they cure slowly by absorbing oxygen from the air (oxypolymerization), forming a complex, cross-linked solid polymer matrix (linoxin).

Question 31Graphic-plastic expression: materials, image-making and project evidence

Comparing linseed oil to walnut oil or poppyseed oil in oil paint formulation, what is linseed oil's main trade-off?

  1. Linseed oil never dries and remains sticky for centuries
  2. Linseed oil turns completely transparent and vanishes
  3. Linseed oil dries fastest and forms the strongest film, but has a higher tendency to yellow over time Correct answer.
  4. Linseed oil causes pigments to lose all color intensity instantly

Explanation

Linseed oil forms the toughest, most elastic dried film and dries relatively quickly among natural oils. However, due to its linolenic acid content, it tends to yellow over time (especially in dark environments), so artists often prefer walnut or poppyseed oil for whites and pale blues.

Question 32Graphic-plastic expression: materials, image-making and project evidence

What is the primary technical purpose of obeying the 'fat-over-lean' (magro sobre graso) rule in oil painting?

  1. To ensure the lower layers dry darker than the top layers
  2. To make the painting resistant to fire and acid
  3. To allow wet oil paint to stick to acrylic varnish without primer
  4. To prevent surface cracking by ensuring flexible, slower-drying oil-rich ('fat') upper layers rest on faster-drying, less flexible oil-poor ('lean') underlayers Correct answer.

Explanation

Lean layers (mixed with solvent like mineral spirits) dry faster and are less flexible. Fat layers (containing more oil) dry slower and remain flexible. Applying fat layers over lean layers ensures top layers flex as lower layers contract, preventing severe cracking (craquelure) and wrinkling.

Question 33Graphic-plastic expression: materials, image-making and project evidence

Which substance is traditionally used as a diluent and solvent to thin oil paint for lean underpainting layers?

  1. Odorsless mineral spirits (esencia de trementina / disolvente inodoro) Correct answer.
  2. Water
  3. Gum arabic solution
  4. Liquid latex

Explanation

Mineral spirits or rectified spirits of turpentine (trementina) dissolve drying oils and resins. Adding solvent to oil paint reduces its oil ratio ('lean') and viscosity, speeding up drying for initial underpainting washes.

Question 34Graphic-plastic expression: materials, image-making and project evidence

What is a 'glaze' (veladura) in painting?

  1. A thick, opaque layer of paint applied with a trowel
  2. A thin, transparent layer of dark or chromatic paint applied over a dry lighter underpainting to alter its hue and depth Correct answer.
  3. A coat of liquid wax burned into wood panel with an iron
  4. A white chalk wash used to obliterate mistakes completely

Explanation

A glaze (veladura) is a transparent film of paint mixed with glazing medium (oil/resin). Applied over a dry underlayer, light passes through the glaze, reflects off the opaque underpainting underneath, and creates luminous visual color mixing and optical depth.

Question 35Graphic-plastic expression: materials, image-making and project evidence

Which term describes applying paint thickly so that brushstrokes or palette knife textures stand out in 3D relief?

  1. Sfumato
  2. Grisaille
  3. Impasto (empaste) Correct answer.
  4. Scumbling

Explanation

Impasto (empaste) refers to applying heavy, viscous paint (using stiff brushes or palette knives) so thickly that textures, ridges, and stroke marks remain clearly visible in dimensional relief on the canvas surface.

Question 36Graphic-plastic expression: materials, image-making and project evidence

What is the fundamental difference between additive color mixing and subtractive color mixing?

  1. Additive mixing uses pigments, while subtractive mixing uses laser beams
  2. Additive color mixing only works in digital photography
  3. Subtractive color mixing increases light brightness with each pigment added
  4. Additive mixing applies to projected light (RGB) where adding colors yields white; subtractive mixing applies to pigments/dyes where combining colors absorbs light towards dark brown/black Correct answer.

Explanation

Additive color mixing involves overlapping light waves (Red, Green, Blue primaries add up to White light). Subtractive color mixing involves physical pigments or dyes that absorb (subtract) specific light wavelengths; mixing primary pigments absorbs more light, resulting in a dark value.

Question 37Graphic-plastic expression: materials, image-making and project evidence

According to Michel Eugène Chevreul's Law of Simultaneous Contrast, what occurs when two complementary colors (e.g., blue and orange) are placed directly side-by-side?

  1. Each color enhances the perceived saturation and brilliance of the other along their shared border Correct answer.
  2. They neutralize each other visually, making both appear dull gray
  3. The darker color turns transparent automatically
  4. Both colors fuse into a silver metallic sheen

Explanation

Chevreul established that when two complementary colors touch, the eye perceives maximum chromatic contrast. Each color projects its optical complement onto the neighboring field, causing both colors to appear at their highest vibrancy and saturation.

Question 38Graphic-plastic expression: materials, image-making and project evidence

In standard color theory systems (such as the Munsell system), what does the term 'chroma' (or saturation/intensity) measure?

  1. The lightness or darkness of a color on a scale from white to black
  2. The purity, vividness, or saturation of a hue compared to neutral gray Correct answer.
  3. The temperature of the studio lights shining on the canvas
  4. The chemical drying time of pigment molecules in hours

Explanation

Chroma (saturación / pureza) measures the purity and intensity of a color. A pure pigment straight from the tube has high chroma, while adding neutral gray or the color's complement lowers its chroma towards a dull mute tone.

Question 39Graphic-plastic expression: materials, image-making and project evidence

Egg tempera (temple de huevo), widely used in Medieval and early Renaissance panel painting, possesses which key operational characteristic?

  1. It remains wet for months, allowing seamless continuous wet blending
  2. It forms thick rubbery sheets that can be peeled off canvas
  3. It dries very rapidly by water evaporation, requiring precise linear hatching (tramado) to build smooth tonal gradations Correct answer.
  4. It dissolves under water even after curing for decades

Explanation

Egg tempera uses fresh egg yolk emulsion diluted with water. As water evaporates, the protein/oil emulsion dries within minutes. Because wet-on-wet blending is impossible over large areas, artists build tonal transitions through tiny cross-hatched strokes (tramado).

Question 40Graphic-plastic expression: materials, image-making and project evidence

Encaustic painting (encáustica), practiced in ancient Fayum mummy portraits, uses which material as its primary binder?

  1. Sodium silicate glass paste mixed with cold water
  2. Animal skin parchment glue boiled with vinegar
  3. Polyvinyl acetate plastic emulsion
  4. Molten beeswax and dammar resin applied with heated tools Correct answer.

Explanation

Encaustic painting involves mixing pigments with molten beeswax and dammar resin. The paint must be applied while hot and fused using heat source (cauterización), producing durable luminous artworks resistant to moisture.

Question 41Graphic-plastic expression: materials, image-making and project evidence

What acrylic paint additive can an artist mix into acrylic paint to extend its drying time ('open time') for softer blending?

  1. Retarder (retardador de secado) Correct answer.
  2. Turpentine
  3. Alcohol
  4. Plaster powder

Explanation

An acrylic retarder (retardador) slows down the evaporation of water and glycol in acrylic paint, extending its open time so artists can blend soft transitions similar to oil painting.

Question 42Graphic-plastic expression: materials, image-making and project evidence

What distinguishes inorganic (mineral/synthetic earth) pigments like Yellow Ochre or Ultramarine from synthetic organic pigments like Phthalo Green or Quinacridone Magenta?

  1. Inorganic pigments dissolve in water, whereas organic pigments only dissolve in alcohol
  2. Inorganic pigments are derived from minerals/metals and tend to be heavy, opaque, and muted; organic pigments are carbon-compound synthetics offering high tinting strength and transparency Correct answer.
  3. Inorganic pigments rot within days, while organic pigments last millions of years
  4. Organic pigments are harvested exclusively from whale oil

Explanation

Inorganic pigments (minerals, calcined earths, metallic oxides like cadmium or cobalt) feature larger crystalline particles, lower tinting strength, and high opacity. Synthetic organic pigments (complex carbon ring chemistry) have tiny particle sizes, extreme tinting strength, and high transparency.

Question 43Graphic-plastic expression: materials, image-making and project evidence

Why have historical pigments like Vermilion (Cinnabar) and White Lead been largely replaced by synthetic alternatives in modern student/studio paints?

  1. Because they turned transparent when exposed to room air
  2. Because they absorb all ambient moisture and melt canvases
  3. Because they contain highly toxic heavy metals (mercury in vermilion, lead in lead white) posing severe health hazards Correct answer.
  4. Because they are transparent dyes that cannot cover white paper

Explanation

Vermilion contains mercury sulfide (HgS) and Lead White contains basic lead carbonate (2PbCO3·Pb(OH)2). Both heavy metals cause severe chronic poisoning (neurological and organ damage) upon inhalation or ingestion, leading to replacement by non-toxic Cadmium hues, Titanium White, and Zinc White.

Question 44Graphic-plastic expression: materials, image-making and project evidence

In watercolor painting, what is the 'lifting' (deslavado / retirado) technique used for?

  1. Lifting paper completely off the wooden drawing board while paint is wet
  2. Glazing dark black ink over wet paper to double color intensity
  3. Applying wax varnish to lift paper weight
  4. Removing wet or re-moistened pigment from paper using a clean damp brush, sponge, or paper towel to create soft highlights Correct answer.

Explanation

Lifting off (retirado) involves absorbing wet watercolor paint or re-wetting dry staining paint and blotting it with a sponge, damp brush, or tissue to lighten areas, reveal paper white, or form clouds and soft specular highlights.

Question 45Graphic-plastic expression: materials, image-making and project evidence

What liquid product (reserva líquida / frisket) is painted onto watercolor paper to preserve pristine white areas from subsequent washes?

  1. Liquid masking fluid (composed of natural rubber latex) Correct answer.
  2. Linseed oil varnish
  3. Acetic acid
  4. Glycerin solution

Explanation

Liquid masking fluid (reserva para acuarela) is a liquid rubber latex solution. Painted onto dry paper, it dries into a water-impermeable barrier. After watercolor washes dry over it, the latex film is rubbed off with a finger or rubber eraser, preserving pure white paper beneath.

Question 46Graphic-plastic expression: materials, image-making and project evidence

In modern subtractive color printing and pigment mixing, why are Cyan, Magenta, and Yellow (CMY) preferred over traditional Red, Yellow, and Blue (RYB) as true primary hues?

  1. RYB primaries cannot be manufactured using mineral pigments
  2. CMY primaries produce a wider, cleaner gamut of secondary mixtures (especially bright purples, violets, and greens) because they reflect narrower, purer spectral bands Correct answer.
  3. CMY colors are completely invisible under ultraviolet light
  4. RYB primaries turn into gold paint when mixed together

Explanation

Traditional RYB primaries are spectral approximations. Red absorbs blue and green light; when mixed with blue, it produces dull muddy purples. Magenta (which reflects red and blue while absorbing green) mixed with Cyan yields brilliant violets and purples, providing a superior subtractive gamut.

Question 47Graphic-plastic expression: materials, image-making and project evidence

Why does Ultramarine Blue lean 'warm' (red bias) while Phthalo Blue leans 'cool' (green bias)?

  1. Ultramarine is heated in ovens to 500°C before packaging
  2. Phthalo Blue contains yellow sulfur crystals harvested from volcanoes
  3. Ultramarine contains trace red spectral wavelengths in its reflection curve, while Phthalo Blue reflects blue-green wavelengths Correct answer.
  4. Ultramarine absorbs all red light completely while reflecting green

Explanation

Pigment color bias depends on spectral reflection curves. French Ultramarine reflects blue along with a small amount of red/violet light (warm bias), making it ideal for mixing purples. Phthalo Blue reflects blue-green wavelengths (cool bias), making it superior for mixing vivid greens.

Question 48Graphic-plastic expression: materials, image-making and project evidence

What is the function of a 'grisaille' underpainting in traditional academic painting methods?

  1. To apply permanent waterproof varnish before painting begins
  2. To seal canvas against attack by wood-boring insects
  3. To create a bright metallic background using silver leaf
  4. To establish precise value relationships, spatial volume, and composition in monochrome gray before applying color glazes Correct answer.

Explanation

Grisaille is a monochrome underpainting executed entirely in shades of gray (or brown/green, like verdaccio). It allows the painter to solve all structural value, shading, and volumetric modeling problems before introducing color through transparent glazes.

Question 49Graphic-plastic expression: materials, image-making and project evidence

In oil painting, what causes the defect known as 'sinking in' (pasado de color / rechupado)?

  1. Oil binder is absorbed out of the upper paint layer down into an overly porous absorbent ground below, leaving top paint matte, dull, and sunken Correct answer.
  2. The heavy lead canvas collapses under its own weight
  3. Paint layers absorb water from humid air and turn into gelatin
  4. Pigment particles sink to the back of the linen canvas

Explanation

Sinking in (rechupado) occurs when paint is applied over an absorbent, under-primed gesso ground. The porous ground sucks up the oil medium from the wet paint above, depriving top pigments of binder and causing them to dry matte, sunken, and desaturated.

Question 50Graphic-plastic expression: materials, image-making and project evidence

How does the elasticity of dry acrylic paint film compare to dry oil paint film over long-term aging?

  1. Acrylic paint turns into powder after 6 months, whereas oil paint turns into soft rubber
  2. Acrylic film remains thermoplastic and flexible over broad temperature ranges, whereas aged oil film oxidizes into a brittle, rigid network prone to cracking Correct answer.
  3. Both films have identical molecular elasticity for thousands of years
  4. Oil paint remains liquid forever, while acrylic turns into glass

Explanation

Dry acrylic paint is a flexible acrylic resin film that retains synthetic elasticity over time. Dried oil paint continues to oxidize over decades and centuries, slowly losing elasticity and becoming increasingly brittle, making oil paintings susceptible to stress cracks when flexed.