Gouache mistakes

Opaque water-based; re-wettable when dry. Thin layers; avoid scrubbing over dry layers.

16 faults, most common first

Colour drying lighter or darker than wet swatchTones that looked balanced on the palette dry significantly darker or lighter on paper. Rescue
Copying every detail of a reference without simplifyingThe drawing is filled with high-contrast, tiny marks spread uniformly across every square centimetre. Rescue
Not checking work in a mirror or at a distanceA portrait or figure exhibits an unintended tilt, an eye sitting higher than its partner, or an overall drift to one side. Rescue
Re-wetting layers lifting colour beneathApplying a fresh brushstroke re-activates dry paint below. Rescue
Subject has no focal pointThe canvas contains equal amounts of detail, contrast, and sharp edges everywhere. Rescue
Colour palette fights: unplanned mix of many chromasThe painting features high-intensity, pure pigment across every corner without a clear dominant hue. Rescue
Composition cut off at awkward placesLimbs, joints, or primary objects hit the boundary of the page in an awkward manner. Partly
Edges ragged where paper is wet by neighbouring paintClean silhouette lines feather and bleed uncontrollably into adjacent areas. Rescue
Local colour only: ignoring reflected light and temperatureThe object is painted using only its local hue mixed with black for shadow and white for highlight. Rescue
Stopping too early because it looks fine in the phone photoThe physical artwork appears faint, lacking rich darks and crisp details, despite reading clearly when photographed. Rescue
Streaky flat areas that should be uniformA flat wash shows uneven brush lines, light bands, and patchy density. Rescue
Tangents: edges kissing awkwardlyTwo distinct edges in the picture touch exactly at their borders without clear overlap. Rescue
Value structure collapses: everything mid-tone and chalkyThe painting has settled into a narrow band of pale, milky mid-tones. Rescue
Cracking when painted too thicklyHeavy impasto marks or thick layers develop hairline fissures and begin to chip away from the surface. Partly
Framing wrongly: cropped or overmattedThe outer border of the frame or mat cuts directly into the subject matter, leaving no margin for the composition to breathe. Rescue
Shapes all similar in sizeThe masses, light patches, or negative spaces across the work are all roughly the same dimensions. Rescue

Faults that apply to every medium are collected on the any medium page. Measuring problems may also be worth checking with the proportion grid, and paint drying questions with the drying time guide.

Checklist: check your work against these

Each line is the quick test from the matching page. Print this page for a studio checklist.

Colour drying lighter or darker than wet swatch. Paint a small swatch, dry it with a hairdryer, and compare it directly against the wet paint on your palette.
Copying every detail of a reference without simplifying. Squint heavily at your source photo; if half the tiny details disappear in your blur, but they are clearly rendered on your paper, you have over-copied.
Not checking work in a mirror or at a distance. Hold the work up to a flat mirror or invert the canvas upside down right now; any lean will jump out immediately.
Re-wetting layers lifting colour beneath. Swipe a slightly damp clean brush across an edge; if colour transfers instantly, the layer is lifting.
Subject has no focal point. Look away for five seconds, then glance quickly at your artwork: if your eyes dart around frantically rather than settling on one clear spot, you have no focal point.
Colour palette fights: unplanned mix of many chromas. Take a photo of your painting and desaturate it halfway; if the composition suddenly becomes calmer and easier to read, your saturation is unmanaged.
Composition cut off at awkward places. Hold your hands or two sheets of paper over the margins to test shifting the crop inward or outward by two centimetres.
Edges ragged where paper is wet by neighbouring paint. Touch the back of your hand to the adjacent paint; if it feels cool to the touch, it is still moist.
Local colour only: ignoring reflected light and temperature. Examine the shadow edge of the object; if it is merely a darker, duller version of the light side, you have missed ambient bounce.
Stopping too early because it looks fine in the phone photo. Step back three metres from the easel in normal room light without your device and see if the darkest darks still hold authority.
Streaky flat areas that should be uniform. Stand two paces back from your work under good light and squint to check if the background reads as a uniform tone.
Tangents: edges kissing awkwardly. Trace the silhouette outlines with your finger to spot any places where two different objects share an identical boundary line.
Value structure collapses: everything mid-tone and chalky. Take a greyscale photo of the painting on your phone; if foreground and background register as the same grey, value structure has collapsed.
Cracking when painted too thickly. Gently flex the corner of your paper or touch the thickest ridge with a fingernail; if flakes break loose, the paint is too thick.
Framing wrongly: cropped or overmatted. Place four scraps of white paper along the edges of your painting to simulate a mount window and see if any focal points get crowded.
Shapes all similar in size. Squint at the artwork and group the elements into basic shapes to see if they all take up roughly equal area.