Paint a glass bottle in Aquarell: suggest transparency with background and edges

Glass transparency is not simply lowering a whole layer's opacity. Glass still has thickness, edges, reflections, and shadows, while much background information remains visible through the middle. Practice these relationships with a simplified half-full bottle: paint the background first, then selectively add edges and tones rather than enclosing the bottle in a white outline.

Give the glass visible background information first

Create a 1200×1500 pixel canvas. Use pale warm gray above and a slightly darker gray-green tabletop below, with their boundary a little below the middle. Place the bottle slightly left of center, about 1000 pixels tall and 420 pixels wide across its body. Keep the background simple: one horizontal division is enough to observe differences inside and outside the bottle.

Separate the background, bottle edges, liquid, and highlights into layers. Lightly sketch the mouth ellipse, narrow neck, shoulders, and base. Let the sides broadly correspond without mechanical symmetry. The base ellipse is wider than the mouth and may have a different curvature; keep both consistent with the chosen viewpoint. Check the centerline first to avoid an unintended lean.

Paint less in the center and vary the edge tones

On the bottle layer, paint the side edges in gray-green or gray-blue. Avoid equal-width outlines: shoulder turns can be broader, straight body sections finer, the lit side lighter, and parts of the opposite side darker. Leave most of the center showing the background, with only a very faint tint to suggest the glass color.

An evenly pale-blue bottle will resemble opaque plastic. Reduce the central color, retain background divisions, and strengthen selected side edges. Glass becomes visible through unevenly distributed information. Some contours can merge into the background, with only hints at their ends; every centimeter need not be outlined.

Use the rim and base to show glass thickness

Draw the mouth with two close elliptical arcs, the front slightly darker and the back lighter, leaving a narrow gap between them. Avoid a thick black ring around the entire rim. Connect both sides of the neck beneath it with short, light shadows at the joins. Curve the shoulders into the body, allowing the two sides to differ in strength with the lighting.

The base is usually thicker than the central body. Suggest it with a few flattened curves and small dark areas, placing the darkest marks at the lower sides or selected tabletop contacts rather than evenly across the bottom. Retain a narrow pale reflection above the base to separate thickness from cast shadow. With the sketch hidden, the rim and base should still describe a three-dimensional container.

The liquid surface is a flattened curve, not a decorative line

Paint the liquid surface roughly halfway up the body as a very flat ellipse, with a clearer front arc and weaker rear arc. Lightly fill the liquid region with a slightly cooler or darker color than the background while retaining its basic tones. Saturated blue makes the bottle look filled with paint. Match the surface to the bottle width without crossing the outer contour.

Where the background's horizontal line passes through the bottle, shift its position or shape slightly within the liquid to suggest refraction, without turning it into arbitrary exaggerated waves. This is simplified drawing, not optical calculation. Preserve continuity outside and slight change inside, then decide whether a stronger change is needed. Reduce it if it overwhelms the bottle's structure.

Use long and short groups of highlight strokes

Choose warm white or another near-white color and a small brush around 8 to 18 pixels. Paint a long highlight on the left, curving from the neck through the shoulder and breaking at the body. Add only two or three short bright edges on the opposite side; avoid symmetry. Vary the highlight width, keep the brightest area tiny, and use gray-white transitions elsewhere.

Add just a short bright mark at the rim and base. Do not add white beside every dark edge or it will become a neon outline. For choosing light and dark edges, see Hard and soft edges on a stone; glass also needs some clear and some disappearing edges, with contrast changes more concentrated.

A cast shadow gives even a transparent object weight

Paint a pale-gray shadow extending down and right on the tabletop, darker where it contacts the base and gradually lighter farther away. Transparent bottles still cast shadows. Leave a small lighter area within it to suggest transmitted light, without making a separate white spot. Keep its width comparable to the bottle and its direction consistent with the light source.

Zoom out and check that the background still passes through the bottle, the rim and base show thickness, highlights are concentrated, and the shadow touches the ground. If only a pale outline remains, strengthen the base and one dark side edge. If it looks ceramic, reduce central paint and continuous outlines. Keep a layered original for comparisons.

Common problems and a color-variation exercise

Can lowering layer opacity create glass? It only lets underlying content show through; it does not automatically create edge reflections, a thick rim, or a liquid surface. Layer opacity helps control existing colors, but the structure must still be drawn. For the related operation, see Layer-opacity tutorial, and do not treat a parameter as the material itself.

Why does the highlight look like a pasted piece of white paper? Common causes are an overly wide shape, excessively regular edges, or a highlight that does not follow the bottle's turns. Break the long highlight into sections, vary its width, and bend it slightly at the shoulder. Next, try pale-green glass while retaining the light-dark positions. Change only edge and liquid colors to observe their effect on transparency.

Finally compare both sides: one may be more continuous while the other has gaps. Do not complete every bright edge for symmetry. Unequal illumination helps readers understand the cylindrical form.

Sources and applicable version

Based on Aquarell official store page for brush, color, and layer capabilities. The public version checked on October 23, 2026 was 1.0.5. The glass effect comes from observation and hand drawing, not automatic refraction simulation, and the interface may change by version.