Hard-edged designs are the ones where a wandering brush shows. On a soft landscape a slightly imperfect boundary disappears into the picture. On a design built from bold blocks of flat color meeting at sharp edges, every wobble is visible from across the room, because the eye has a straight line to compare it against.
The good news is that clean lines are almost entirely a matter of technique rather than a steady hand, and the technique is learnable in an evening.
One thing to say plainly first, since people arrive here looking for abstract kits: our own catalog is representational — cabins, wildlife, coastlines, florals and farmsteads. We do not make abstract designs. Everything below applies to any design with hard edges, which includes buildings, boats, fences, lettering and the geometric parts of any painting.
Why edges go wrong
Three causes, in order of how often they are the culprit.
Too much paint on the brush. A loaded brush releases paint the moment it touches the canvas, and it keeps releasing as you move. The bead of paint runs ahead of the bristles and over the line. This is the cause about three quarters of the time.
Paint that is too thin. Watered-down acrylic wicks along the weave of the canvas past where you put it. It will find the printed line and cross it, and there is nothing you can do with the brush to stop it.
Pushing rather than pulling. If you work from the middle of a section outward, you are driving paint at the boundary. If you work from the boundary inward, you are drawing it away.
The technique
Do the edge first, then fill. Outline the section with a fine brush along the inside of the printed line, then flood the middle with a larger brush while the outline is still wet. The two merge and the boundary is already correct before you touch the bulk of the area.
Pull the brush toward the center. Set the tip down just inside the line and draw it inward. Never work the other way.
Use the edge of the brush, not the point. This is the one that surprises people. A round brush pressed lightly on its side gives a longer, straighter contact with the canvas than the tip does, and it follows a line far more accurately. A flat or angled brush is better again — the flat side laid along the boundary produces a clean edge in one movement.
Move the canvas, not your wrist. Your hand draws a comfortable arc in one direction and an awkward one in the other. Turn the canvas so the line you are painting runs the comfortable way. Painters do this constantly and beginners almost never think of it.
Rest your hand. Anchor your little finger on the canvas or on a piece of card laid over a dry area, and move from the fingers rather than the whole arm. An unsupported hand wobbles no matter how steady you are.
Slow down on the edge, speed up in the middle. The boundary is perhaps ten percent of the work and ninety percent of what is visible.
Consistency, not water
Straight from the pot is usually right. Acrylic in a paint by numbers kit is mixed to the consistency that covers in one or two coats and stays where it is put.
If a pot has stiffened, add water a drop at a time with a cocktail stick and stir it in properly rather than tipping water in. If a color is too thin to hold its edge, leave the lid off for a few minutes and stir.
Pale colors need two coats, and this is where edges get lost. The temptation is to lay the second coat on thickly to cover the printed number in one go, and thick paint spreads. Two normal coats with the first properly dry beats one heavy one.
About masking tape
It works on some surfaces and we would not use it here. Tape on a printed canvas can lift the printing or the primer when it comes off, particularly on a canvas that has any paint on it already, and you can end up removing the very line you were trying to protect. If you want to try it, test on the blank margin outside the printed area first, and use the lowest-tack tape you can find.
The brush-edge technique above gets you a cleaner line than tape does anyway, because a printed boundary is rarely perfectly straight and tape is.
Let neighbors dry
Two wet sections meeting at a hard edge will bleed into each other whatever you do. If a design has adjacent blocks of strongly contrasting color, paint one, let it dry, then paint the other up against it. Working one color at a time right across the canvas gives you that drying time for free, which is a good reason to do it beyond the obvious efficiency.
Where an edge is meant to be soft — a sky into cloud, water into reflection, the shaded turn of something round — the opposite applies and you want both wet at once. Knowing which is which is most of the craft. Our guide to blending on a numbered canvas covers the soft half of it.
Fixing a line that has gone wrong
While it is wet: do not wipe. Wiping spreads it. Take a clean brush, damp and pressed out, and lift the stray paint by touching it and drawing away. Two or three light touches take up most of it.
Once it is dry: let it dry completely first, then repair with the correct neighboring color rather than with white. Load a fine brush, and re-cut the edge from the correct side. Acrylic is opaque enough to cover itself, so a wandering dark line can be trimmed straight by painting the light color back up against where the line should be.
What not to do: do not paint over a mistake with white to start again — white under a color changes it, and you will see the patch. Do not scrape wet paint with a fingernail or a blade; you will damage the primer. Do not use rubbing alcohol or solvent on the painting, because acrylic is soluble in both and you will take the surrounding work with it.
Working position
Good light from the side, so the printed lines throw a slight shadow and are easier to see. The canvas tilted rather than flat, so you are looking at the surface square on instead of at an angle — a line looks straight from directly above and curved from the side. And breaks before your hand gets tired, because the last half hour of a long session is where most of the damage happens.
Our note on choosing an easel covers getting the canvas to a sensible angle, and what is in a kit and what each part does covers the brushes. You can see the designs in the full collection — the ones with architecture, boats and fences are where this technique earns its keep.
