gouache paint
Enable an agent to recognise gouache paint, assess its usable condition and determine suitable preparation, application, reworking and storage actions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an agent to recognise gouache paint, assess its usable condition and determine suitable preparation, application, reworking and storage actions.
Gouache is a water-thinned paint formulated for opacity: a hydrophilic binder (classically gum arabic), a high loading of colouring pigment, and usually an inert white extender such as precipitated calcium carbonate, so the dried film is matte, hides the support by light scatter, and - in gum-bound grades - remains redispersible with water.
It can be Prepare a working portion by controlled wetting, dilution or remixing where the formulation permits.; Mix colours and make dried comparison swatches before matching a target colour.; Apply covering passages or diluted washes under recorded support and coat conditions.; Test and control lifting, rewetting and disturbance of earlier layers.; Assess dried or separated paint for recoverability using a small trial portion.; Select storage, cleanup and disposal actions from the paint's observed condition and product-specific instructions..
Distinguishing features
Check product identification and binder information to distinguish conventional gouache from acrylic gouache; the word 'gouache' alone does not settle dried-film behaviour.
Compare coverage over light and dark areas at a recorded dilution and application thickness; deliberate covering use supports identification as gouache, but opacity alone cannot distinguish it from poster paint or opaque watercolour.
Test a sacrificial dried swatch with water and record softening, colour release and lifting; interpret the result alongside binder information rather than treating reactivation as a conclusive identity test.
Inspect a dried swatch for surface sheen and visible brush texture under consistent lighting; a matte appearance is supporting evidence, not sufficient identification.
Compare declared intended use and formulation with watercolour, poster paint and tempera products where visual and wetting tests overlap; retain an unresolved identity when the evidence does not separate them.
Scope
+ Identification of the paint and its declared binder, pigments and formulation family
+ Supplied consistency, dilution, mixing and brush application behaviour
+ Opacity, colour and surface appearance under recorded application conditions
+ Drying, water reactivation and disturbance during layering
+ Material deterioration, recoverability and formulation-specific handling constraints
- The composition, meaning, authorship and value of a finished artwork
- Manufacture and condition of brushes, palettes and other painting tools
- Independent specifications and deterioration of paper, board and other supports
- Container design and closure mechanisms beyond their effects on the paint
- General pigment chemistry and binder production processes
- Conservation treatment of an entire painted object
Characteristics
- Declared formulation family
- conventional gouache | acrylic gouache | other declared formulation | unresolved Controls which assumptions about dilution, drying and reactivation may be used.
- Binder identification
- declared binder or binder mixture; unknown permitted Helps distinguish similarly labelled paints and choose compatible working methods.
- Pigment identification
- declared pigment names or Colour Index identifiers; mixture or undisclosed Colour names alone do not establish mixing behaviour, permanence or handling constraints.
- Supplied and current paint form
- paste | fluid | moist cake | dry cake | dried residue | other observed form Separates an intended dry presentation from accidental drying and determines preparation needs.
- Working dilution
- added water mass per paint mass, g/g, with the starting paint state recorded Makes observations of flow and covering behaviour interpretable.
- Coverage at working conditions
- transparent | partially covering | covering; record support, dilution and coat conditions Determines whether the paint can obscure an underlayer or must be used as a translucent wash.
- Wet-to-dry colour change
- paired colour readings or colour difference under a named method and lighting condition Supports colour matching using the intended final dry appearance.
- Dried surface sheen
- matte | satin | glossy | uneven; record viewing and application conditions Supports appearance matching and detection of unexpected surface variation.
- Water reactivation response
- readily reactivates | partly reactivates | no observed reactivation | untested; record drying age and test Determines whether dried paint can be reused, lifted or disturbed by a wet overlayer.
- Support compatibility
- paint formulation linked to a tested support and preparation, with observed adhesion and surface response Prevents a successful application on one support from being assumed valid on another.
- Paint condition
- apparently usable | separated | unintentionally dried | gritty | suspected contamination | unresolved Directs inspection, trial recovery or withdrawal from use.
- Product-specific handling evidence
- link to the applicable label, technical instructions and safety information Grounds handling and disposal decisions in the actual formulation.
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Gouache identity and formulation Establishes what the paint is and which formulation-dependent behaviours may be expected.
Gouache can be confused with neighbouring paint types, and similar product names do not guarantee the same binder or reactivation behaviour.
Product and material identity
Connects the observed material to its declared product identity and composition.
Formulation evidence
Record the declared paint family, binder and pigment information, separating documented information from inference.
- What label or technical information identifies this material as gouache and specifies its binder? provenance
- Which pigment identifiers and formulation details are declared for this particular colour? definition
Neighbouring paint boundaries
Evaluates ambiguity with acrylic gouache, opaque watercolour, poster paint and tempera.
Identity discrimination
Use documentation and limited swatch tests together, retaining ambiguity where their results overlap.
- What evidence separates this paint from opaque watercolour, poster paint or tempera? boundary
- Does the declared binder and observed dried-swatch water response require acrylic-gouache-specific handling? boundary
Coverage and dried colour Records how the paint covers underlying colour and what appearance remains after drying.
An agent must distinguish colour in the container from the appearance and covering performance of an applied gouache passage.
Covering performance
Assesses opacity under explicit dilution, support and coat conditions.
Conditional opacity
Treat coverage as an observed application result rather than a universal property of every gouache colour.
- How much of a light-and-dark test pattern remains visible through a dried coat at the intended dilution? measurement
- What dilution or additional coat achieves the required coverage without unacceptable surface buildup? action
Dry appearance
Compares wet and dry colour and evaluates the resulting surface sheen.
Dry colour reference
Maintain a dried swatch reference for matching colour and finish under the intended viewing conditions.
- How do lightness, hue and saturation change between the wet application and its dry swatch? measurement
- Is the dried surface sufficiently matte and uniform for the intended passage? measurement
Working consistency and mixing Connects the supplied paint state to a usable brush mixture and repeatable colour mixtures.
Gouache preparation must balance brush flow, coverage and the condition of paint taken from a tube, cake or palette residue.
Water and brush response
Records controlled preparation and its effect on application.
Usable working mixture
Identify a preparation that gives the required brush release and coverage for the intended mark.
- What starting paint state and added-water ratio produce the required brush flow? measurement
- Does a trial stroke show unwanted drag, beading, pooling or loss of coverage that requires adjustment? action
Colour mixture control
Tracks component paints and the dry performance of their mixtures.
Repeatable colour mixtures
Record mixture components and proportions alongside a dried result rather than relying on colour names.
- Which identified paints, proportions and water additions produced the dried reference mixture? provenance
- Does the mixture retain the required coverage, colour and finish when reapplied? measurement
Drying, reworking and supports Determines how an applied passage behaves during drying, later wetting and contact with its support.
Layering and correction depend on whether the underlying paint moves, lifts or remains attached under the next operation.
Rewetting and overpainting
Assesses reactivation and the effect of wet brushwork over a dried passage.
Underlayer disturbance
Record the conditions under which water or overpainting moves an existing paint layer.
- After a recorded drying interval, how much colour lifts or moves under a controlled damp-brush test? measurement
- What brush moisture, pressure and number of passes permit the intended overpainting or correction? action
Paint-support interface
Evaluates the applied paint on a specific support and surface preparation.
Adherence and layer integrity
Record beading, powdering, cracking, flaking or other visible failures without assigning an unverified cause.
- On which support and preparation was adherence and dried-layer integrity assessed? provenance
- Does the intended coat thickness remain intact during the handling or flexing expected for this support? measurement
Paint condition and retention Assesses whether stored or leftover gouache remains usable and what evidence governs continued use.
Dryness, separation and contamination require different decisions, while permanence and handling constraints can vary by product and colour.
Condition and recovery
Distinguishes intended dry paint from deterioration and evaluates recovery on a trial portion.
Recoverability assessment
Determine whether remixing or rewetting restores usable paint without assuming that all gouache formulations recover.
- Is the observed dryness or separation consistent with the supplied form and formulation, or evidence of changed condition? boundary
- Does a small permitted recovery trial restore a smooth mixture and acceptable dried swatch, or should use stop pending further assessment? action
Permanence and handling evidence
Links colour-specific durability information and product instructions to intended use and retention.
Evidence-based use constraints
Keep permanence ratings and handling instructions attached to the identified product rather than generalising across gouache.
- What product- and colour-specific evidence supports use under the intended light exposure, and which rating method was used? provenance
- What storage, cleanup and disposal actions follow from the applicable product instructions and observed paint condition? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Traditional artist gouache (gum-arabic binder, high pigment load, chalk or blanc-fixe extender)
- Designers' / poster gouache (extra-opaque graphic grades, often more extender)
- Acrylic gouache / acryla gouache (polymer-emulsion binder; matte and opaque but water-resistant when dry)
- Student, school, and poster-colour grades (economy extenders, variable lightfastness)
- Pan (cake) gouache versus tube (moist) gouache
- Metallic, pearlescent, and interference gouache
- Fluorescent / neon gouache
- Historical bodycolour (opaque watercolour made by adding white, formerly often lead white)
- Which of these kinds and varieties hold for the sense of gouache paint this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q204330 - Item for gouache as medium/paint; technique-as-work may be linked separately.
- Getty Art & Architecture Thesaurus - 300015163 - AAT concept 'gouache (paint)'.
- Harmonized System - 3213.90 - Artists' colours in other forms; sets of watercolours are often 3213.10 rather than gouache tubes.
- CAS (binder, not the paint) - 9000-01-5 - Gum arabic in traditional formulations; acrylic gouache uses emulsion polymers instead.
- Colour Index - C.I. Pigment / C.I. Constitution numbers of the colourants in a given tube - Identifies pigments in a product, not gouache as a class.
- Which of these identifiers and schemes hold for the sense of gouache paint this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- ASTM D4236 (ASTM International) / U.S. Labeling of Hazardous Art Materials Act (15 U.S.C. §1277): chronic-hazard labeling of art materials, including gouache.
- ACMI AP (and former CL) certification (Art and Creative Materials Institute), evaluated against ASTM D4236.
- EN 71-3 (CEN) and ISO 8124-3: migration of certain elements, applied when school poster colour / gouache is sold as a toy or for young children.
- Regulation (EC) No 1907/2006 REACH (EU): registration and restriction of substances (pigments, preservatives, extenders) in the formulation.
- California Proposition 65 (OEHHA): warning duties for listed pigments such as certain cadmium and lead compounds in some professional colours.
- Which of these standards and regulation hold for the sense of gouache paint this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Graphic design, poster, and illustration comps where flat, camera-ready opaque colour is needed.
- Fine-art painting and mixed water-media, including highlights and corrections in watercolour (bodycolour).
- Fashion, botanical, and scientific illustration; historical animation and cel/background painting.
- Art-school still-life and colour-training (especially in Eastern Europe and parts of Asia).
- Plein-air and urban sketching in pans or tubes.
- Children's and classroom poster colour.
- Scale models, miniatures, and matte scenic/prop work where a non-gloss film is wanted.
- Which of these real-world use hold for the sense of gouache paint this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Retail tube fill (artist lines) - 14-15 (some brands 20-37) - mL
- Wet-paint pH (gum/chalk grades) - about 7-9 - pH
- Lightfastness of the colourant - ASTM I-II in serious artist lines; III-V or unrated for many fluorescents and student reds/pinks - ASTM lightfastness class (or Blue Wool 1-8)
- Specular gloss of the dry film - matte, generally well below satin acrylics; often described as near-zero sheen - gloss units (typically 85° geometry if instrumented)
- Practical gum-film thickness before cracking - thin washes to low-build layers; cracking common in millimetre-scale impasto - mm
- Dry value shift - noticeable lightening versus the wet mass-tone (the familiar 'dries lighter' effect) - dimensionless (visual); ΔL* if measured
- Which of these typical measurements hold for the sense of gouache paint this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Brittle cracking, flaking, or powdering when gum-arabic films are applied too thick or on a flexing support.
- Rewetting: later water-media lifts or muddies underlayers; finished work remains vulnerable to moisture and abrasion.
- Dry-lightening and chroma drop that make wet colour-matching unreliable.
- Fugitive colour, especially fluorescent, some lakes, and cheap student pigments.
- Mold in pans or dried pots if the preservative system is weak or the box is stored damp.
- Poor adhesion over oily, waxy, or some acrylic films; conversely, water from gouache disturbs soluble underlayers.
- Inhalation or ingestion hazard from toxic historical or professional pigments (cadmium, cobalt, and, in old bodycolour, lead white) and from dust if a dry film is sanded.
- Contact allergy to isothiazolinone and similar in-can preservatives in some modern tubs.
- Which of these failure modes and hazards hold for the sense of gouache paint this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- United Kingdom: 'bodycolour' is the watercolour-studio name for opaque white or gouache used inside a transparent watercolour.
- United States: 'opaque watercolor' is a common synonym; school 'tempera' is usually poster paint, not egg tempera.
- Japan: acrylic gouache (e.g. Holbein Acryla Gouache) is a major commercial class; schools use 'poster colour'.
- South Asia: 'poster colour' is the everyday art-college and school name for opaque gum or PVA poster paint.
- German-speaking practice often says Deckfarbe ('covering colour') alongside Gouache.
- Russian and other Eastern European academies treat гуашь as a core training medium rather than a designers' specialty.
- Francophone use of gouache names both the material and the opaque water-media technique.
- Which of these regional variation hold for the sense of gouache paint this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Transparent watercolour - Drawdown over dark paper or a black/white contrast card: gouache hides the ground; watercolour relies on paper white showing through.
- Acrylic (emulsion) paint - After a full dry, a damp brush redissolves gum gouache and does not redissolve acrylic; acrylic films are usually glossier unless a matte medium is used.
- Acrylic gouache - Same rewet test as above: polymer-bound 'acrylic gouache' looks matte and opaque but becomes water-resistant; traditional gouache does not.
- Casein paint - Binder is milk protein, often with an ammonia odour; fully cured casein is much less readily rewet than gum gouache.
- Egg tempera - Egg-yolk binder, typically hatched in thin layers and water-resistant when cured; not a chalk-filled gum paint.
- Distemper (glue-size scene paint) - Animal-glue binder, coarser grind, architectural or theatrical use; not tube-artist gouache even though both dry matte and opaque.
- School poster paint / so-called tempera - Often the same aqueous-opaque family at lower pigment volume and lightfastness; grade and labeling, not a different optical test.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of gouache paint this model covers, and on what evidence? provenance
Sources
- Gouache - Conservation-materials description of gum-bound opaque water paint, extenders, rewetting, and distinction from watercolour.
- gouache (paint) - Authoritative vocabulary identity for the paint (as distinct from gouache painting as a technique).
- Gouache - Museum glossary account of opaque watercolour, bodycolour, and studio use.
- The Artist's Handbook of Materials and Techniques - Studio chemistry of gum-arabic paints, opacity, fillers, and handling faults of gouache and bodycolour.
- ASTM D4236 Standard Practice for Labeling Art Materials for Chronic Health Hazards - The principal U.S. chronic-hazard labeling practice that artist and student gouache sold there is required to follow.
- gouache (Q204330) - Wikidata item commonly used as a cross-catalogue identifier for gouache.
What the second pass must settle
- Does the registry intend gouache paint to include acrylic gouache, or should this entry reference a neighbouring formulation model?
- Which documented criteria reliably distinguish conventional gouache from products sold as opaque watercolour, poster paint or tempera when formulation disclosure is incomplete?
- Which practical test procedures make coverage, wet-to-dry colour change and reactivation observations comparable across formulations?
- What evidence distinguishes recoverable drying or separation from irreversible deterioration or contamination in particular gouache formulations?
- How applicable are manufacturer permanence ratings to heavily diluted passages, mixtures and different supports?