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Catalonia PAU Graphic-Plastic Expression Techniques study materials
Catalonia PAU Graphic-Plastic Expression Techniques study resources

Catalonia PAU Graphic-Plastic Expression Techniques practice questions

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

In the standard graphite pencil grading system, what determines the hardness and dark value of a pencil lead?

  1. The ratio of graphite powder to kaolin clay, where more clay creates harder, lighter lines. Correct answer.
  2. The addition of vegetable wax, where higher wax content yields harder and paler marks.
  3. The baking temperature during manufacture, where higher heat produces darker and softer leads.
  4. The thickness of the wooden casing surrounding the graphite core.

Explanation

Graphite pencil cores are manufactured by firing a mixture of powdered graphite and kaolin clay. Increasing the proportion of clay increases lead hardness (H grades), yielding fine, light lines, whereas increasing graphite content creates softer, darker leads (B grades).

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

How does natural vine charcoal differ fundamentally from compressed charcoal in composition and graphic performance?

  1. Vine charcoal is charred willow twigs without binders, producing easily blendable, erasable marks, whereas compressed charcoal includes gum binder for darker, permanent tones. Correct answer.
  2. Vine charcoal contains synthetic wax binders that resist erasing, while compressed charcoal is pure carbonized wood.
  3. Vine charcoal is made by pressing pulverized coal into sticks, while compressed charcoal is made from carbonized vine tendrils.
  4. Vine charcoal produces dense, waterproof black lines, while compressed charcoal creates light grey powdery strokes.

Explanation

Vine charcoal consists of carbonized wood sticks (willow or vine) burnt in an oxygen-deprived kiln without added binders, allowing easy manipulation and dusting off. Compressed charcoal mixes ground charcoal with a binder (like gum or clay) to form dense, dark, adhered strokes.

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

Which binder formulation distinguishes soft pastels from oil pastels?

  1. Soft pastels use minimal gum tragacanth or methyl cellulose, while oil pastels use non-drying mineral oil and wax binders. Correct answer.
  2. Soft pastels use linseed oil binders, while oil pastels use egg yolk emulsion.
  3. Soft pastels are bound with synthetic acrylic resin, while oil pastels use gum arabic.
  4. Soft pastels rely on animal hide glue, while oil pastels contain no binders whatsoever.

Explanation

Soft pastels consist of pure pigment held together by a minimal aqueous binder such as gum tragacanth or cellulose, producing a velvety, friable powder. Oil pastels combine pigment with a non-drying mineral oil and wax matrix, resulting in a buttery, smudge-resistant stroke.

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

What is the traditional pigment origin and characteristic color of sanguine drawing chalk?

  1. Natural red iron oxide (hematite), producing warm reddish-brown and terracotta tones. Correct answer.
  2. Calcined bone black, producing cool charcoal grey tones.
  3. Cuttlefish ink sacs, producing dark greyish-brown tones.
  4. Hydrated ferric oxide (goethite), producing bright lemon yellow tones.

Explanation

Sanguine is a traditional drawing medium made from natural red earth rich in hematite (ferric oxide). It produces characteristic warm terracotta, brick red, and reddish-brown tones widely favored during the Renaissance for figurative sketches.

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

Why does silverpoint drawing require a specially prepared abrasive ground on the support?

  1. Silver metal is too hard to deposit particles on smooth paper without a slightly abrasive tooth containing bone ash or white pigment. Correct answer.
  2. The ground chemically dissolves the silver wire to create liquid metal ink on contact.
  3. Unprepared paper causes silver wire to melt due to friction heat.
  4. Silver wire only adheres to flexible gel mediums applied in thick coats.

Explanation

Silverpoint involves dragging a fine silver wire across a surface. Because silver is a hard metal, raw paper cannot shear off metal particles; the support must be coated with a slightly abrasive ground (traditionally bone dust, chalk, and glue) to shave off tiny silver particles.

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

What primary visual tradeoff occurs when applying a spray fixative to a soft pastel drawing?

  1. The fixative prevents smudging but tends to darken light values and reduce the luminous pastel bloom. Correct answer.
  2. The fixative lightens all dark values into pastel pink and chalky white.
  3. The fixative converts dry pastel powder into waterproof oil paint.
  4. The fixative dissolves paper fibers, rendering the support transparent.

Explanation

Spray fixatives contain resin dissolved in alcohol or solvent that coats pastel particles to lock them to the paper. However, filling the air gaps between pigment particles alters light refraction, which darkens highlights and dampens the characteristic velvety bloom.

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

What is the function of a tortillon or blending stump (estompe) in dry media drawing?

  1. To rub and smear dry media particles across paper fibers, creating smooth continuous gradations and soft atmospheric shadows. Correct answer.
  2. To cut fine highlight channels by scraping away paper fibers.
  3. To apply liquid solvent that chemically bleaches dark charcoal strokes.
  4. To coat the drawing with an airtight waterproof varnish.

Explanation

A tortillon or blending stump (estompe) is a tightly rolled paper tool used to blend charcoal, graphite, or pastel. It pushes dry media particles into the paper tooth, softening sharp transitions and creating continuous tonal gradations.

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

What materials comprise traditional Conté crayons, invented by Nicolas-Jacques Conté in 1795?

  1. A compressed mixture of graphite or iron oxide pigment, clay, and a small binder base. Correct answer.
  2. Pure beeswax mixed with synthetic aniline dyes.
  3. Ground marble dust suspended in linseed oil emulsion.
  4. Pure carbonized vine charcoal bound with gum arabic and chalk.

Explanation

Conté crayons were created during wartime shortages by combining pulverized graphite or natural earth pigments (sanguine, sepia) with clay and a wax/binder base, formed into square section sticks that yield rich, velvety lines.

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

How does paper texture or 'tooth' (graine/grana) affect the application of dry media like charcoal and soft pastel?

  1. A prominent tooth provides microscopic valleys that trap dry pigment particles, enabling multiple rich layers, whereas smooth paper holds very little pigment. Correct answer.
  2. A prominent tooth repels dry pigment, causing it to fall off immediately unless wet water is applied.
  3. Smooth paper absorbs dry pigment into its core fibers, while rough paper blocks pigment penetration completely.
  4. Paper tooth has no effect on dry media performance and only influences oil painting absorbency.

Explanation

The 'tooth' of paper refers to its surface roughness and grain texture. High-tooth papers have pronounced peaks and valleys that mechanically abrade and hold friable dry particles (pastels, charcoal), permitting dense value layering.

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

What visual transformation occurs in a completed silverpoint drawing over time due to environmental oxidation?

  1. The initial pale grey metallic lines slowly oxidize, darkening into a warm sepia or warm brown patina. Correct answer.
  2. The silver lines turn neon green due to copper oxide reactions.
  3. The silver lines completely vanish as the metal sublimates into the atmosphere.
  4. The lines expand into thick black liquid blobs due to atmospheric moisture.

Explanation

When freshly drawn, silverpoint lines appear as delicate grey metallic strokes. As the microscopic silver particles react with airborne sulfur and oxygen over time, they tarnish, developing a characteristic warm brown or sepia patina.

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

Why is a kneaded eraser (goma moldeable) preferred over a rigid vinyl eraser for delicate charcoal and pastel highlight work?

  1. It can be shaped into fine points and lifts dry pigment by adhesion without abrading paper fibers or leaving eraser crumbs. Correct answer.
  2. It contains solvents that dissolve paper sizing to permanently bleach pigment.
  3. It deposits white chalk pigment onto the paper while removing dark strokes.
  4. It hardens into a permanent glass shield that seals dry charcoal underneath.

Explanation

A kneaded eraser is a pliable rubber putty. It lifts friable charcoal and pastel particles cleanly through surface adhesion when dabbed or pressed, leaving no abrasive friction residue and preserving paper surface integrity.

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

In classical chiaroscuro drawing, where is the 'core shadow' (sombra propia / terminator) located on a curved form?

  1. Along the zone where light transitions into shadow, representing the darkest area of the form's surface before reflected light strikes. Correct answer.
  2. Directly at the point of specular reflection facing the light source.
  3. On the background surface cast by the object blocking the light beam.
  4. Inside the highlight zone where white paper is left unworked.

Explanation

The core shadow (or terminator) is the darkest zone on the form itself, occurring where the surface turns completely away from the primary light source, just before secondary reflected light illuminates the shadow side.

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

At a microscopic level, what force primarily holds binderless natural charcoal particles onto rag paper fibers prior to fixing?

  1. Van der Waals surface forces and mechanical entrapment within interlocking cellulose microfibrils. Correct answer.
  2. Chemical covalent bonding between carbon atoms and paper cellulose.
  3. Magnetic attraction driven by iron impurities in the charcoal.
  4. Electrostatic repulsion between negatively charged paper and charcoal.

Explanation

Binderless charcoal lacks chemical adhesives. Particles remain on paper through mechanical entrapment in paper fiber crevices combined with weak Van der Waals physical surface forces, which explains why unfixed charcoal is highly vulnerable to smudging.

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

Why did Nicolas-Jacques Conté invent the modern clay-graphite pencil manufacturing process in 1795?

  1. The Napoleonic trade blockade cut off France's supply of pure lump graphite from Borrowdale, England, necessitating a mixture with local clay. Correct answer.
  2. To produce colored pencils by substituting graphite with synthetic acrylic dyes.
  3. To create waterproof drawing leads suitable for underwater naval cartography.
  4. Because natural graphite deposits worldwide had become completely exhausted.

Explanation

Until 1795, high-grade pencils used solid natural graphite cut directly from Borrowdale, England. When the French Revolutionary Wars blocked English graphite imports, Conté patented a method of mixing powdered lower-grade graphite with refined clay and firing it, establishing the modern pencil grading process.

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

What structural role does kaolin clay play during the high-temperature kiln firing of graphite pencil leads?

  1. It vitrifies into a rigid ceramic matrix that binds graphite particles together and controls lead hardness. Correct answer.
  2. It melts into liquid glass that coats graphite particles to make them transparent.
  3. It reacts with graphite to form metallic aluminum carbide crystals.
  4. It acts as a blowing agent that introduces microscopic air bubbles to make the lead soft.

Explanation

During firing at over 1000°C, kaolin clay undergoes ceramic vitrification, forming a durable silicated matrix holding graphite grains. The higher the ceramic clay ratio, the denser and harder the ceramic matrix, resulting in harder (H) pencil grades.

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

What primary carbon pigment and binder combination forms traditional waterproof India ink (tinta china)?

  1. Amorphous carbon soot (lampblack) bound with shellac or gum arabic solution. Correct answer.
  2. Ground charcoal bound with drying linseed oil.
  3. Iron sulfate mixed with oak gall tannic acid.
  4. Crushed lapis lazuli bound with egg white albumen.

Explanation

Traditional India ink combines fine carbon black soot (lampblack) with an aqueous binder like gum arabic or shellac. Shellac-based formulations dry to a tough, water-resistant film that withstands wet washes.

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

What binder is traditionally used in watercolor paint (acuarela) to maintain water solubility and luminous transparency?

  1. Gum arabic (acacia tree sap), often enriched with honey or glycerin plasticizers. Correct answer.
  2. Walnut drying oil mixed with turpentine.
  3. Nitrocellulose lacquers dissolved in acetone.
  4. Molten beeswax mixed with dammar varnish.

Explanation

Watercolor relies on natural gum arabic, a water-soluble plant binder harvested from acacia trees. Glycerin or honey is added to retain moisture, allowing the paint to re-wet easily while producing transparent luminous washes over white paper.

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

How does gouache (opaque watercolor) differ from transparent watercolor in terms of formulation and optical qualities?

  1. Gouache contains a higher pigment concentration and inert white fillers (like chalk or barium sulfate) to create an opaque, matte paint film. Correct answer.
  2. Gouache uses linseed oil as a vehicle, making it completely waterproof upon drying.
  3. Gouache contains no binder and relies entirely on static electricity to adhere to paper.
  4. Gouache is transparent when wet but turns silver and metallic upon drying.

Explanation

Gouache is formulated like watercolor with gum arabic binder, but incorporates inert white pigments (such as precipitated chalk or titanium dioxide) and higher pigment loading, producing flat, opaque matte layers that obliterate underlying marks.

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

What natural binder forms the core emulsion in traditional egg tempera (temple al huevo)?

  1. Egg yolk emulsified with water, containing natural lipids and protein binders. Correct answer.
  2. Whipped egg whites (glair) mixed with vinegar and linseed oil.
  3. Boiled egg shells pulverized into liquid lime water.
  4. Whole dried egg powder dissolved in turpentine.

Explanation

Egg tempera uses fresh egg yolk separated from the white. The yolk is a natural lipid-protein emulsion containing lecithin, which allows oil and water components to remain stably suspended, producing a fast-drying, durable paint film with a satin luster.

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

Which drying oil is most widely used as the primary binder in oil paint due to its durable polymerizing film?

  1. Cold-pressed linseed oil. Correct answer.
  2. Non-drying olive oil.
  3. Essential mineral spirits.
  4. Volatile spike lavender oil.

Explanation

Linseed oil (pressed from flax seeds) is the classic binder in oil painting. It undergoes oxidation and polymerization to transform from a liquid into a flexible, insoluble poly-linoleic film.

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

What key drying behavior characterizes synthetic acrylic paints (pintura acrílica)?

  1. They dry rapidly through water evaporation, causing the acrylic polymer particles to coalesce into a flexible, water-resistant film. Correct answer.
  2. They dry by absorbing carbon dioxide from the surrounding air over several months.
  3. They remain permanently water-soluble even decades after drying.
  4. They require baking in a thermal kiln at 500°C to cure.

Explanation

Acrylic paint consists of pigment suspended in an acrylic polymer emulsion. As water evaporates, the microscopic synthetic resin spheres coalesce into a tough, flexible plastic film that is completely insoluble in water once cured.

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

In traditional oil painting, what defines a 'glaze' (glacis)?

  1. A thin, transparent layer of pigment-rich oil medium applied over a dry, lighter underpainting to modify its tone and create optical depth. Correct answer.
  2. A thick, opaque paste scraped onto the canvas with a palette knife to build high relief textures.
  3. A heavy coat of white gesso painted over damaged canvas areas.
  4. A layer of water-based ink sprayed onto wet oil paint to cause beads.

Explanation

A glaze (glacis) is a thin, translucent veil of paint diluted with oil and varnish medium. Applied over a cured underpainting (like grisaille), light travels through the transparent film, reflects off the lower layer, and produces luminous depth.

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

What visual and tactile characteristic defines the impasto (empaste) technique in painting?

  1. Applying thick, undiluted paint that retains brushstrokes and palette knife ridges, casting real physical shadows on the canvas. Correct answer.
  2. Applying paper-thin washes of diluted watercolor that bleed into flat staining fields.
  3. Polishing cured paint surfaces with sandpaper until they resemble reflective marble.
  4. Stippling microscopic dots of primary color that blend optically at a distance.

Explanation

Impasto involves laying down heavy, viscous paint in thick relief marks. The resulting raised strokes catch light and cast physical surface shadows, adding tactile texture and dynamic energy to the artwork.

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

What fundamental chemical process permanently locks pigments into a wall during buon fresco (true fresco) painting?

  1. Slaked lime (calcium hydroxide) absorbs carbon dioxide from the air, transforming into calcium carbonate crystal that encapsulates the pigments. Correct answer.
  2. Linseed oil in the wet plaster polymerizes when exposed to sunlight.
  3. Egg yolk proteins form a rubberized waterproof skin over dry plaster.
  4. Silica in the sand melts into a sheet of solid glass under atmospheric pressure.

Explanation

In buon fresco, inorganic pigments suspended in water are applied onto fresh, wet lime plaster (intonaco). As the calcium hydroxide, $\text{Ca(OH)}_2$, in the plaster reacts with atmospheric $\text{CO}_2$, it converts to calcium carbonate, $\text{CaCO}_3$, locking pigment particles into the rock-hard wall matrix.

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

How does fresco secco (dry fresco) differ procedurally and structurally from buon fresco?

  1. Fresco secco is painted on dry plaster using organic binders (like casein, egg, or glue), making it less durable and prone to flaking. Correct answer.
  2. Fresco secco is painted on wet plaster without pigments using pure transparent water.
  3. Fresco secco embeds pigments into molten bronze cast into the wall.
  4. Fresco secco is indestructible and completely immune to dampness compared to buon fresco.

Explanation

Fresco secco is executed on dry plaster. Because there is no active carbonation process occurring in dry lime, pigments require added organic binders (egg, casein, animal glue) to adhere. This surface layer lacks the chemical integration of buon fresco and is more susceptible to moisture damage and peeling.

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

Which material binder and thermal tool are essential for working in traditional encaustic painting?

  1. Purified beeswax combined with resin, worked using heated irons or cauteria to fuse paint layers. Correct answer.
  2. Gum arabic mixed with ice water, applied with frozen brushes.
  3. Sodium silicate glass paste, cured with ultraviolet laser lights.
  4. Liquid synthetic latex rubber, cured with cold nitrogen gas sprays.

Explanation

Encaustic painting (practiced in ancient Egypt and Greece) utilizes molten beeswax mixed with dammar resin and pigment. Artists apply the warm fluid wax and fuse each layer using a heat source (cauterium, heat gun, or iron) to bond the wax layers.

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

What is the primary technical reason for adhering to the 'fat over lean' (graso sobre magro) rule in multi-layered oil painting?

  1. Upper paint layers must contain more oil ('fatter') than lower layers to remain more flexible; otherwise, fast-drying lean top coats will crack over slow-drying oil underlayers. Correct answer.
  2. Lower layers must be soaked in pure mineral oil to prevent upper water-based paints from drying.
  3. Lean paint contains wax that repels upper layers unless applied last.
  4. Fat layers contain solvent that evaporates rapidly, sealing underlayers from air completely.

Explanation

In oil painting, 'lean' layers contain more solvent and less oil, drying faster and forming a stiffer film. 'Fat' layers contain a higher proportion of oil medium, drying more slowly into a flexible film. Applying lean fast-drying layers over slow-drying fat underlayers causes surface cracking (craquelure) and delamination.

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

Why has historical iron gall ink caused severe paper deterioration (ink corrosion / ink gall erosion) in historical manuscripts over centuries?

  1. Excess iron vitriol (ferrous sulfate) releases sulfuric acid, which chemically hydrolyzes cellulose fibers and eats holes through the support. Correct answer.
  2. The ink attracts paper-eating termites due to high sucrose content.
  3. Iron gall ink undergoes expansion when exposed to light, blowing paper apart mechanically.
  4. The ink dissolves rag paper by converting cellulose into water-soluble sugar syrup.

Explanation

Iron gall ink is made from oak gall tannins, ferrous sulfate, and gum arabic. Free iron(II) ions induce Fenton reactions that generate free radicals, while residual sulfuric acid breaks down paper cellulose chains through acid hydrolysis, eventually creating charred holes in written areas.

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

How do line quality and nib flexibility compare between a traditional reed pen (caña) and a modern flexible steel nib pen (pluma de acero)?

  1. Reed pens produce rigid, expressive, slightly blunt strokes with rapid ink discharge, whereas flexible steel nibs yield variable line weights responding sensitively to pressure changes. Correct answer.
  2. Reed pens create hair-thin lines that expand automatically under water, while steel nibs produce uniform chalky lines.
  3. Reed pens require electrical power to operate, whereas steel nibs are completely stiff like glass tubes.
  4. Reed pens deposit oil paint, while steel nibs work only with dry pastel dust.

Explanation

Cut reed pens (made from hollow cane) are relatively stiff and porous, depositing bold, angular, rhythmic strokes that exhaust ink quickly. Steel dip nibs feature precision slits and flexible tines that spread under downward pressure to produce smooth transitions from hairline thins to thick swells.

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

What defines the technique of wash drawing (aguada) in ink or monochrome watercolor?

  1. Applying liquid ink diluted with varying proportions of water using soft brushes to create delicate, continuous value gradations. Correct answer.
  2. Scraping dry pigment onto wet oil paint with a wire brush.
  3. Spraying opaque white lacquer through stencils to build embossed textures.
  4. Soaking the entire paper sheet in black dye until it turns uniformly opaque black.

Explanation

Wash drawing (aguada) involves diluting water-soluble ink or watercolor pigment with clean water. Soft hair brushes apply these transparent washes in layered glazes or wet-on-wet transitions to build form, atmosphere, and value depth.

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

What is the organic origin and drying characteristic of casein paint (pintura al casein)?

  1. It uses phosphoprotein derived from milk precipitate curdled with lime or acid, drying to a hard, water-insoluble matte film. Correct answer.
  2. It uses synthetic petroleum resins that dry into rubbery transparent sheets.
  3. It uses pine tree rosin dissolved in alcohol, remaining soft and sticky indefinitely.
  4. It uses gelatin from boiled fish bones that re-dissolves instantly with ambient humidity.

Explanation

Casein is an ancient protein binder extracted from skim milk curd. When mixed with an alkali (like lime or ammonium carbonate) and pigments, it forms an exceptionally durable, opaque matte paint film that becomes highly water-resistant upon curing.

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

Why is describing the hardening of oil paint as 'drying' technically inaccurate from a chemical standpoint?

  1. Oil paint does not dry by solvent evaporation; it cures through oxidative polymerization, absorbing oxygen to cross-link linoleic acid chains into a linoxyn matrix. Correct answer.
  2. Oil paint hardens because water inside the oil evaporates into the atmosphere within seconds.
  3. Oil paint solidifies through freezing as room temperature drops below 30°C.
  4. Oil paint hardens through nuclear decay of heavy metal pigments.

Explanation

Unlike water-based media that harden via simple evaporation of water, drying oils (linseed, walnut) contain unsaturated fatty acids that undergo autoxidation and cross-linking polymerization. This chemical transformation gains weight by absorbing atmospheric oxygen, turning liquid oil into solid linoxyn resin.

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

In Renaissance buon fresco, what was a 'giornata' and how did it dictate the artist's working sequence?

  1. The specific area of fine plaster (intonaco) laid down for a single day's work, which had to be fully painted while remaining wet before the plaster carbonated. Correct answer.
  2. The wooden scaffolding system built to reach high church ceilings.
  3. The full-scale paper drawing transferred to the wall using charcoal dust pouncing (spolvero).
  4. The final coat of egg varnish applied over dry fresco after one year.

Explanation

In buon fresco, painting must occur while the intonaco (final smooth lime-sand plaster layer) is damp. The master fresco artist plasterer laid down only as much intonaco as could be painted in one day-termed a 'giornata' (day's work). Plaster edges were beveled at nightfall to join seamlessly with the next day's patch.

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

What rheological property does a thixotropic gel painting medium exhibit during brush application?

  1. It becomes fluid and workable under mechanical shearing from brushstrokes, but rapidly recovers a firm gel structure when at rest, preventing sags and drips. Correct answer.
  2. It expands by 200% in volume when exposed to friction, filling cracks automatically.
  3. It liquefies permanently and turns into gas when shaken.
  4. It hardens instantaneously into solid glass upon touching animal hair bristles.

Explanation

Thixotropy describes time-dependent shear-thinning behavior. Under the mechanical shearing force of a paintbrush, a thixotropic medium thins out to flow easily. Once brush agitation stops, the medium recovers its viscous gel state, holding thick impasto peaks without slumping.

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

What chemical breakdown risk occurs if oil paint is applied directly onto an unprimed, highly alkaline fresh lime ground?

  1. Saponification: free fatty acids in drying oil react with alkaline calcium hydroxide to form soluble soaps, destroying the paint film. Correct answer.
  2. Rapid crystallization: oil turns into diamond carbon crystals within hours.
  3. Fermentation: oil converts into ethyl alcohol and carbon dioxide bubbles.
  4. Sublimation: oil bypasses the liquid state and turns into carbon gas.

Explanation

Strongly alkaline materials (like fresh lime plaster or unneutralized cement) react chemically with the ester bonds and fatty acids of drying oils. This ester hydrolysis process is saponification-literally converting the oil binder into soft, sticky metal soaps that liquefy and destroy paint adhesion.

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

In traditional woodcut relief printing (xilografía), which part of the wooden matrix receives ink and prints onto paper?

  1. The raised, uncut original surface of the wood block. Correct answer.
  2. The carved-out hollow grooves recessed below the surface.
  3. Only the metal pins embedded into the edges of the block.
  4. The reverse uncarved side of the wooden board.

Explanation

Woodcut is a classic relief process (grabado en relieve). The artist gouges out negative areas. Ink rollers coat only the remaining raised surface peaks, which transfer ink onto damp paper under pressure.

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

What matrix material and carving tools characterize linocut printmaking (linograbado)?

  1. Linoleum sheets (cork dust and linseed oil on burlap backing) carved with V-shaped and U-shaped gouges. Correct answer.
  2. Polished copper plates etched with diamond scrapers.
  3. Limestone blocks polished with carborundum powder.
  4. Silk mesh screens coated with photo emulsion.

Explanation

Linocut utilizes linoleum, a synthetic substrate made of oxidized linseed oil, cork dust, and wood flour pressed onto a burlap backing. Its smooth, grainless texture allows gouges (gubias) to cut easily in any direction without splintering.

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

How are lines created on a metal plate during the etching process (aguafuerte)?

  1. An acid-resistant ground is scratched away with an etching needle to expose raw metal, which is then bitten by an acid bath. Correct answer.
  2. Lines are carved into soft wood using electric saws.
  3. Ink is drawn onto damp paper using wax crayons.
  4. Heavy steel hammers punch deep round holes into aluminum plates.

Explanation

Etching (aguafuerte) is a chemical intaglio process. A metal plate (copper, zinc) is coated with an acid-resistant varnish. The artist draws with a needle, exposing raw metal lines. Submerging the plate in acid (nitric acid or ferric chloride) etches or 'bites' grooves into the exposed metal.

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

What characteristic structural feature of drypoint (punta seca) produces its signature soft, velvety printed line?

  1. The raised metallic burr (rebaba) thrown up beside the scratched groove, which traps extra ink during wiping. Correct answer.
  2. The deep acid-bitten trenches that hold liquid watercolor.
  3. The smooth glass beads glued onto the metal surface.
  4. The rubber stencil mask used to block ink spray.

Explanation

In drypoint (punta seca), a sharp needle scratches directly into a metal or plastic plate without acid. The needle plows up a ridge of displaced metal called a burr (rebaba). Inking traps rich ink under this burr, creating fuzzy, velvety printed edges.

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

What physical-chemical principle governs traditional lithography (litografía)?

  1. The mutual chemical repulsion between greasy hydrophobic substances and water on a flat planographic surface. Correct answer.
  2. The difference in electrical conductivity between gold and silver.
  3. The mechanical scratching of deep grooves into hardwood blocks.
  4. The optical absorption of ultraviolet light by gelatin stencils.

Explanation

Lithography (invented by Alois Senefelder) is a planographic process based on the chemical antipathy of oil and water. The artist draws with greasy crayons on porous Bavarian limestone or zinc. Dampening the stone with water causes non-image areas to hold water and repel greasy ink, while greasy image areas attract ink.

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

How is ink transferred onto paper or fabric during serigraphy (serigrafía / screen printing)?

  1. A flexible rubber squeegee (racleta) forces ink through open mesh areas of a stretched fabric screen onto the substrate underneath. Correct answer.
  2. A heavy steel roller crushes a metal plate to squeeze ink out of deep grooves.
  3. Ink is dabbed by hand using leather tampons onto raised wooden blocks.
  4. A laser beam burns ink particles directly into paper fibers.

Explanation

Serigraphy is a stencil printing process. Fine polyester or silk mesh is stretched over a frame, and non-printing areas are blocked with stencils or exposed photo-emulsion. A rubber blade called a squeegee (racleta) sweeps across the screen, pushing ink through open mesh pores onto the print substrate.

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

What material and process are used in aquatint (aguatinta) to achieve subtle tonal areas in intaglio printmaking?

  1. Finely powdered rosin resin (colofonia) dusted onto a metal plate and melted by heat to create a porous acid-resistant grain. Correct answer.
  2. Liquid wax brushed thickly over carved wooden boards.
  3. Sandpaper rubbed over damp paper under heavy press rollers.
  4. Crushed glass fused onto steel plates with gas torches.

Explanation

Aquatint allows intaglio plates to print tonal washes (as seen in Goya's prints). Powdered rosin (resina de colofonia) is dusted uniformly across a copper/zinc plate and heated until resin specks melt onto the metal. Acid etches thousands of tiny rings around the melted dots, creating a reticulated field that holds tonal ink.

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

What line profile and clean surface structure characterize a line engraved with a burin (buril) on a copper plate?

  1. V-shaped grooves carved by pushing a diamond-section steel tool, with metal curls scraped away to leave clean, crisp, precise line edges. Correct answer.
  2. Rough jagged furrows flanked by tall burrs that trap velvety ink bleeds.
  3. Shallow circular pits created by dripping nitric acid through eye-droppers.
  4. Wavy melted trenches formed by dragging hot soldering irons.

Explanation

Burin engraving (grabado a buril) is a rigorous intaglio technique. The artist pushes a lozenge- or V-shaped hardened steel chisel (burin) across a copper plate. The tool carves out a clean V-shaped ribbon of metal, which is scraped off with a scraper to ensure precise, crisp lines without soft burrs.

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

How does an artist work from dark to light in the mezzotint (manera negra) technique?

  1. The entire copper plate is systematically pitted with a serrated rocker (mecedora) to print solid black, then highlights are scraped and burnished smooth. Correct answer.
  2. The plate is painted white with gesso, and black ink is scratched away using needles.
  3. The plate is submerged in acid until it completely dissolves into liquid copper.
  4. Black paper is bleached using chlorine drops applied with fine camel brushes.

Explanation

Mezzotint is a reductive 'dark-to-light' intaglio process. The artist rocks a curved, multi-toothed steel tool (rocker/mecedora) thousands of times across the copper plate to cover it in a uniform burr field that prints velvety black. Scrapers and burnishers flatten selected burrs to create midtones and silky white highlights.

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

Why does an intaglio printing press (tórculo) utilize heavy pressure cylinders combined with dampened rag paper and felt blankets?

  1. High roller pressure forces soft, damp paper fibers deep into the etched metal grooves to pick up recessed ink, aided by resilient felt blankets. Correct answer.
  2. The heat from the cylinders melts the metal plate into liquid ink on contact.
  3. Damp paper acts as an electrical insulator to prevent static shocks.
  4. The felt blankets wipe all ink off the plate surface before paper touches it.

Explanation

Intaglio inks reside below the plate surface in recessed grooves. The tórculo press forces a bed carrying the plate, damp paper, and wool felt blankets between two heavy steel rollers. The cushions compress damp, pliable paper fibers down into the etched grooves to lift out the ink.

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

Why is a monotype (monotipia) classified as a unique graphic artwork rather than a standard edition print?

  1. The image is painted directly onto an uncarved smooth matrix (glass/metal) and transferred once, consuming most paint and preventing identical second prints. Correct answer.
  2. It is printed on edible paper that dissolves after one viewing.
  3. The matrix explodes automatically when passed through the press rollers.
  4. It is created by casting molten lead into sand molds.

Explanation

Monotype (monotipia) is a hybrid painting-printmaking process. An artist paints fluid ink or oil paint onto a smooth, non-porous matrix (glass, acrylic, metal) with no permanent engraved or carved grooves. Pressing transfers the painted image to paper; since almost all wet ink transfers in one pull, identical editions cannot be pulled.

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

In original printmaking editioning, what does the pencil notation 'P.A.' (or 'E.A.') and a fraction like '12/50' signify below the image margin?

  1. 'P.A.' indicates Proof of Artist (Prueba de Artista / Épreuve d'Artiste) outside the main run; '12/50' indicates the 12th individual print in an edition limited strictly to 50 copies. Correct answer.
  2. 'P.A.' stands for Plastic Acrylic paint, while '12/50' means 12 percent pigment and 50 percent binder.
  3. 'P.A.' means Photo Reproduction, and '12/50' signifies 12 years of warranty out of 50 total.
  4. 'P.A.' designates Public Archive, and '12/50' indicates a sale price of 12 Euros and 50 Cents.

Explanation

Pencil documentation at the bottom of an original print follows strict conventions. 'P.A.' (Prueba de Artista / Épreuve d'artiste) designates artist proof impressions reserved for the creator (typically 10% of edition size). The fraction '12/50' indicates print number 12 out of a numbered limited edition of 50 prints.

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

What unique textural impressions can be produced on an etching plate using soft ground (barniz blando)?

  1. Tacky, non-drying varnish allows pressing leaves, fabrics, or paper textures onto the plate, lifting ground to etch physical organic textures in acid. Correct answer.
  2. It coats plates in hard glass that prevents any acid biting, producing completely blank white prints.
  3. It creates glowing fluorescent colors when exposed to sunlight without ink.
  4. It dissolves the metal plate into liquid mercury upon contact with paper.

Explanation

Soft ground etching (barniz blando) utilizes a sticky varnish containing tallow or grease that remains soft. When textured materials (lace, leaves, feathers, coarse cloth) or paper drawn on with a pencil are pressed into the ground and peeled off, they pull away ground in exact textural patterns for acid biting.

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

How does wood engraving (xilografía a testa / end-grain woodcut) differ from traditional side-grain woodcut (xilografía al hilo)?

  1. Wood engraving uses dense end-grain blocks of hardwood (like boxwood) carved with fine steel burins, enabling miniature detail and high-volume press runs. Correct answer.
  2. Wood engraving uses soft softwood planks carved with large axes to make rough poster prints.
  3. Wood engraving is an acid etching technique performed on wooden boards coated with copper plating.
  4. Wood engraving replaces wood with rubber sheets printed without ink under water.

Explanation

Traditional woodcut cuts parallel to the tree grain on plank wood (al hilo), where wood fibers split easily under fine gouges. Wood engraving (pioneered by Thomas Bewick) uses cross-section end-grain blocks (a testa) of extremely hard boxwood, allowing burins to cut delicate line work in any direction without splitting.

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

Why is modern commercial offset lithography described as an 'indirect' printing method?

  1. The inked image on the flat printing plate transfers first to an intermediate rubber cylinder blanket, which then offsets the image onto paper. Correct answer.
  2. The artist draws the image while looking into a mirror across the room.
  3. The printing press operates automatically without using any electric power or mechanical gears.
  4. Ink is sprayed into the air and falls onto paper by gravitational settling.

Explanation

Commercial offset lithography is 'indirect' because the metal plate does not touch paper directly. Inked plate cylinders transfer (offset) the image onto a flexible rubber blanket cylinder, which in turn presses the ink onto paper, preserving plate life and producing right-reading impressions.