In the long-term process of observing and making watercolor paints and other auxiliary materials, the pigment itself acts as a variable.

The object of observation here is not the finished watercolor paint, but the pigment itself in its powder state, as well as the process of the pigment moving from powder form to binding with the medium.

The observations focus on how pigments behave under different material conditions, including changes in state, binding, dispersion, and long-term stability.

The pigments observed so far fall into four basic categories:

1. Standard artist-grade pigment powders
2. Mica-based metallic and pearlescent pigments
3. Chameleon (color-shifting) pigments
4. High-brightness fluorescent pigments

These different categories exist as powders with distinct material properties, creating unique variables in subsequent observations.

1. Physical and Morphological Variables of the Pigment Itself

The most direct variables come from the pigment itself. Different pigments have different physical states before meeting the binder.

Particle size, particle shape, density, weight, water affinity, and surface condition all affect how the material behaves later. Pigments are not uniform powder materials.

1.1 Particle Size and Texture

(1) Pigment particles show varying degrees of coarseness or fineness. Some pigment powders are extremely fine, while others show larger visible particle structures.

(2) Particle size affects how the pigment comes into contact with other materials. Once the pigment enters the binder, differences appear in how the particles disperse, clump, and ultimately form the material structure:

Particle Size → Dispersion State → State After Binding

(3) The fineness or graininess felt in the dry powder state continues to exist after combining with the binder.

1.2 Density and Weight

(1) Different pigments have different inherent densities. Two pigment powders with similar volume may actually contain different amounts of physical mass.

(2) After entering the binder, differences in density show up as:

• Different settling speeds
• Different layering behaviors
• Different amounts of buildup at the bottom of the container
• Different states of re-dispersion after stirring

(3) The pigment's own weight connects with particle size, density, and the actual amount taken. When different pigments reach the same volume, their weights are not necessarily equal. Powder volume and actual material weight are two independent variables.

1.3 Water Affinity and Wetting Response

(1) Different pigments respond differently to water-based binder systems. Some pigments mix easily with water-based systems, while others have a weaker affinity for water. When pigment enters a water-based binder system, it displays varying degrees of wetting, dispersing, clumping, and binding.

(2) Pigments that dislike water or are extremely fine need longer grinding or mechanical processing to change how they contact the binder system.

1.4 Structural Features and Multi-Sensory Physical Behaviors

(1) Different pigment categories show distinct physical and visual features due to their structure:

• Standard artist pigments: Main variables show up in particle size, density, water affinity, dispersion, settling, and clumping.
• Mica metallic/pearlescent pigments: Involve flake structures, surface characteristics, and optical effects, accompanied by settling and layering phenomena.
• Chameleon pigments: Their structure creates extra variables based on viewing angles, lighting conditions, and binding states, also accompanied by settling and layering.
• Fluorescent pigments: Involve lighting conditions and visual brightness; the powder is physically very light.

(2) Transparency changes depending on the pigment, binder, moisture state, and degree of dryness.

(3) Some pigments carry noticeable odors inherent to the material itself. Odors stimulate human perception, creating two paths: "the pigment's own smell" and "the effect of the smell on the person."

(4) During stirring and mechanical work, light pigments (such as fluorescent, metallic, and chameleon pigments) or certain fine standard pigments easily float up into the surrounding air from inside the container. Dusting levels range from low dust, light dust, noticeable dust, to high dust.

2. Pigment-Binder Mixing and Grinding Variables

When pigment meets binder, it does not always form a uniform state immediately. Different pigments show different degrees of binding with the binder:

Pigment Type → Binder Response → State of Combination

Some pigments mix smoothly into the binder system, while others show distinct specks, clumping, separation, or local settling. A clear distinction must be made between individual particles, small clusters, and large lumps.

2.1 Thickness and Flow Response

Combining the same binder system with different pigments creates different levels of overall thickness. Some pigments flow easily after mixing, while others become thick and heavy.

2.2 Mechanical Responses and Process Phenomena

Different pigments respond differently under mechanical force:

1. Grinding time and method: The grinding time and mechanical action needed to reach a stable mixture vary by pigment.
2. Stirring resistance: In liquid state, different pigments create different feeling of drag and resistance when stirred.
3. Audible response (sound): During grinding, scraping, and moving, different audible sounds are produced due to particle size, structure, thickness, and friction.
4. Drying and crusting: During grinding, contact with air, tools, and the work surface creates local drying or crusting. Crusts vary in thickness, hardness, and looseness. Residual material sticks to the surface to varying degrees, affecting how easy it is to clean.

3. External Environment, Tools, and Human Factors

Pigments do not change in isolation. External materials, the surrounding climate, tools, and human actions form a system of variables.

3.1 External Environment and Materials (Climate, Binder, and Water)

(1) Natural environment: Changes in seasons, weather, temperature, and humidity directly affect pigment behavior, leading to changes in drying times and internal material structures.

(2) Binder system: Includes ingredients such as gum arabic, honey, glycerin, clove oil, ox gall, and water. Different binder recipes trigger different responses from the same pigment.

(3) Water works across multiple stages:

• Early stage: Helps prepare the binder system and clean tools.
• Middle stage: Added in appropriate amounts during the pigment-binder mixing process as needed.
• Late stage: Helps dry paint flow again and cleans up tools.

3.2 Tools and Containers

Tools change how people interact with pigments:

1. Stirring tools, muller, pallet knives: Size, shape, material, and surface texture alter the mechanical force applied to the material (such as moving, gathering, surface smoothing, transferring, and scraping container walls).
2. Straining tools: Structure, mesh size, and cleanliness affect the size of particles left behind.
3. Containers and pans: The size, depth, shape, material, and surface condition of containers change how pigment spreads out. The specifications of the final pans (size, material, wall thickness) create new combinations of variables.

3.3 Human Factors and Indirect Effects on Environment/Body

(1) People participate throughout the entire process: selecting pigments (distinguishing artist-grade from industrial, plastic, or food-use pigments), comparing materials (checking binding, particle state, clumping, settling, and long-term storage), preparing binders, making practical judgments, and storing the final product.

(2) During drying and storage, changes inside the material caused by the environment (such as hollow gaps forming) trigger human judgments on whether to top up or fix those internal gaps.

(3) Indirect variables include:

• Tiny pigment particles escaping into the air, changing the work environment.
• Skin contact and cleanup: Pigments stick to skin with varying strength. Cleaning up moves through levels: "simple paper towel wipe → water cleanup → soap/cleaner required" based on remaining residue.

4. Interface Behaviors and State Changes

Once pigment enters the container (pan), surface behaviors and state changes occur.

4.1 Container Wall Behaviors

1. Sticking and flaking: Some pigment sticks to the inside walls of the pan. Later, parts of this material flake off the wall and are placed back into the pan to be fixed in place.
2. Staining the container: Long-term contact with certain pigments leaves permanent color stains on the container itself (such as white plastic pans).
3. Flow and spillover: When liquid paint fills up near the edge, some pigment flows down the sides and spills over the border onto surrounding surfaces, leaving new surface residue.

4.2 Color State Changes

Pigments look different at different stages:

1. Powder → Wet (Liquid)：Some pigments look darker when mixed into the binder than in powder form, as the visual features of the binder itself join the final appearance.
2. Wet → Dry state: As water evaporates, the pigment's color shade and transparency change.

5. Continuous Behaviors During Drying and Long-Term Storage

Pigment behaviors continue long after mixing or pouring is done.

5.1 Phenomena During Drying

Different pigments move from wet to dry in different ways:

• Drying time: Influenced by ambient environment (seasons, temperature, humidity) alongside inherent pigment traits; different pigments change at different speeds.
• Shrinking and cracking: Some pigments shrink significantly in volume as they dry; others develop fine surface lines or deep cracks.
• Temporary separation: Some materials show a brief separation between pigment and binder along the surface while drying.
• Bubbles and internal gaps: Air bubbles created earlier can stay through drying, altering the surface texture; some pigments form a hard outer skin while drying, leaving hollow gaps inside.
• Density changes: The drying process is accompanied by volume changes, structural tightening, and shifts in density state.

5.2 Long-Term Storage and Stability

Over long periods of storage, pigment systems display the following behaviors:

1. Powder moisture absorption: Pigment in powder form clumps together when exposed to humid environments.
2. Settling and caking: In liquid mixtures, pigment gradually settles to the bottom—some stays loose, while some packs into hard lumps.
3. Wall residue: Pigments cling to container walls, leaving material residue behind.
4. Layering and uneven distribution: In multi-pigment mixtures, differences in density and particle size cause local layering or uneven color distribution. Mixed pigment smells also differ from single pigment smells.
5. Bubbles, foam, and overflow: Some pigments generate bubbles and surface foam during liquid storage. Foam moves upward and causes liquid to rise and spill out over the bottle opening.
6. Scent changes and mold: Smells alter after long storage; occasionally, mold appears in certain material mixes.
7. Visible changes: Under long air and light exposure, changes in color, structure, smell, or surface condition that can be confirmed by the naked eye are recorded, without guessing unverified chemical causes inside.

5.3 Reactivation and Tool Residue

(1) When dried pigment meets water again, it flows once more. Different pigments require different amounts of time and water to reactivate. Reactivated pigment carries the history of its first mixing, drying, hardening, and re-wetting.

(2) Pigments leave residue on tools and containers. Some wash off easily, while others leave strong color stains that permanently change the surface condition of tools and pans.

6. Summary Structure of Variables

Pigment variables are grouped into six main levels:

• 1. Pigment Physical & Morphological Variables: Pigment category, particle size, texture feel, density, weight, water affinity, transparency, odor, powder dusting into air.
• 2. Mixing & Grinding Variables: Wetting and dispersion, binding degree, clumping/lumping, thickness, grinding time and method, stirring drag, grinding sound, surface drying/crusting.
• 3. External Materials, Climate, Tools & Human Variables: Weather/season/temperature/humidity, binder recipe, water, stirring/grinding/straining tools, pan/container types, human selection/judgments on filling gaps, skin attachment and cleaning residue.
• 4. Container Interface & State Changes: Wall sticking/flaking and refixing, container staining, spillover, color/transparency changes from powder to wet to dry.
• 5. Drying Process Variables: Drying speed, volume shrinkage, temporary separation, surface cracking, bubble effects, internal hollow gaps, volume change/structural tightening/density shifts.
• 6. Long-Term Storage & Reactivation Variables: Moisture absorption in powder, settling/caking in liquid mixes, wall residue, multi-pigment layering/separation, foam overflow, scent changes, mold growth, reactivation time and water needs, tool staining and residue.

7. Overall Definition

Pigment variables refer to how pigment powders—based on their own particle structure, density, water affinity, weight, and material traits—behave when contacting binder systems, water, tools, containers, external weather conditions (seasons/temperature/humidity), and human operation, showing up as dispersion, binding, clumping, settling, caking, separation, structural drying changes, and long-term condition shifts.

In the entire material observation system, no single pigment variable decides the result alone. What shapes material behavior is a combined system:

Pigment itself + Binder system + Water + Tools + Containers + Person + Environment + Time

The pigment itself is the starting point of the system, and its behavior runs through the initial powder state, the middle mixing and drying process, and the long-term storage and reactivation stages.

Through making handmade watercolor paints over many years, different pigment behaviors have been observed and recorded. Parts of this process have been filmed, organized, and archived under pigment behavior records. The physical results of these pigment behaviors are organized and displayed as art supplies and materials on VHaquarell.