OSAT Art (102)

Painting involves applying pigment suspended in a binder to a surface. Different media have distinct properties, handling characteristics, and historical associations.

Oil paint uses drying oils, typically linseed, as a binder. It dries through oxidation rather than evaporation, allowing extended working time and exceptional blending capabilities. Oil paints offer rich color saturation, transparency through glazing, and thick impasto application.

The fat over lean principle requires that each paint layer contain more oil than the layer beneath to prevent cracking. Underpainting establishes composition and values before color application. Grisaille uses monochromatic underpainting, often in gray. Verdaccio employs greenish underpainting, traditionally used for flesh tones. Glazing applies thin, transparent layers over dried paint to modify color and create luminosity. Scumbling drags opaque paint over dry layers, allowing underlying colors to show through textures. Alla prima or direct painting completes work in a single session while paint remains wet.

Oil painting supports include stretched canvas, canvas boards, wood panels, and paper prepared with sizing or gesso. Grounds prepare surfaces to receive paint, with traditional gesso made from rabbit skin glue and chalk, and acrylic gesso offering a modern alternative. Mediums modify paint consistency and drying time, including linseed oil, stand oil, damar varnish, and alkyd mediums.

Acrylic paints suspend pigment in acrylic polymer emulsion, drying quickly through water evaporation to form a flexible, water-resistant film. Acrylics can mimic oil or watercolor effects depending on dilution and application. They adhere to most surfaces without extensive preparation and do not yellow with age.

Acrylic mediums expand the paint's possibilities. Gel mediums increase body and transparency. Modeling paste creates textured surfaces. Fluid mediums improve flow for watercolor-like effects. Retarders slow drying time, extending blending opportunities. Glazing mediums enhance transparency while maintaining body. Interference and iridescent mediums add optical effects.

Acrylic techniques include wet-on-wet blending, which requires speed due to rapid drying; layering and glazing similar to oils but with faster working pace; pouring and dripping for fluid abstractions; and mixed media applications, since acrylics bond well with collage elements. Heavy body acrylics hold texture and brush marks; fluid acrylics flow smoothly for detailed work.

Watercolor paint consists of finely ground pigment in a water-soluble binder, typically gum arabic. It is characterized by transparency, with white paper providing luminosity rather than white paint. Watercolor values are controlled by water-to-pigment ratios.

Watercolor techniques depend on timing and moisture control. Wet-on-wet application drops paint into wet paper or paint, creating soft edges and unpredictable blooms. Wet-on-dry applies paint to dry surfaces for crisp edges. Graded washes transition smoothly from dark to light or between colors. Lifting removes pigment from wet or rewetted surfaces with brushes, sponges, or tissue. Masking fluid preserves white areas during painting. Dry brush drags paint across textured paper for broken, textural marks. Granulation uses certain pigments that settle into paper texture, creating granular effects.

Watercolor papers vary in weight, texture, and sizing. Heavier papers resist buckling; stretching prevents warping on lighter weights. Cold-press papers have moderate texture; hot-press papers are smooth; rough papers have pronounced texture.

Gouache is opaque watercolor, containing more pigment and often chalk or other opacifiers. Unlike transparent watercolor, gouache allows light values over dark and can be reworked by rewetting. Colors may shift slightly between wet and dry states, typically drying lighter.

Gouache works well for illustration, design mockups, and studies. Its matte finish reproduces well in print. Application techniques overlap with watercolor but include opaque layering and corrections impossible in transparent watercolor.

Egg tempera uses egg yolk as a binder, creating thin, translucent layers that build color through hatching rather than blending. It dries quickly and permanently, with a characteristic matte surface. Tempera was the primary painting medium before oil paint's development.

Encaustic painting uses pigmented beeswax mixed with damar resin, applied hot and fused with heat. It creates unique textural and translucent effects, with a luminous surface quality. Encaustic can embed collage elements and be carved or scraped. Safety requires proper ventilation and temperature control.

Fresco is mural painting on plaster. Buon fresco applies pigment to wet lime plaster, chemically bonding paint to the wall as plaster dries. It requires rapid, confident application, since sections must be completed before plaster sets. Fresco secco applies paint to dry plaster, creating a less permanent bond. Sinopia refers to preliminary drawings on the wall surface, visible in damaged frescoes.

Brushes vary in shape, size, and fiber type. Bristle brushes made from hog hair hold heavy paint and create texture. Sable and synthetic soft brushes suit detail work and fluid media. Round brushes create variable lines; flat brushes make bold strokes and sharp edges; filbert brushes combine qualities; fan brushes blend and texture; liner brushes paint fine lines.

Palette knives mix paint and apply it directly to surfaces, creating bold, textural effects. Surfaces include canvas, panel, paper, and unconventional supports. Stretcher bars support canvas; keys or wedges adjust tension. Panels offer rigid, smooth surfaces; cradling prevents warping on large panels.