Let it cure for a few days, dust it dry, varnish it if you want to, and keep it out of direct sun. That is most of it. The one part worth reading carefully is framing, because the advice you will find elsewhere assumes a canvas with margins that a paint by number usually does not have.
First, let it cure
Acrylic is touch-dry in minutes and cured much later. Touch-dry is not the same thing. Paint that feels solid can still dent under a fingernail or transfer onto anything laid against it.
Give it 24 hours before you handle the canvas at all, and several days before varnishing or framing. Thickly painted sections, the ones where you laid down two coats to cover a dark number, take longest. In a humid room, add a couple of days. Press gently on the thickest area with a clean finger; if it feels cool or slightly tacky, it is not ready.
Cleaning
Before varnishing, dry only. A soft, clean, lint-free cloth or a wide dry brush lifts dust without moving pigment. Do not use water, and certainly not household cleaner or rubbing alcohol, on unvarnished acrylic. Alcohol softens and dissolves it.
Once a canvas has been varnished, it is far more robust. A barely damp cloth over the varnish is fine then, and is the only cleaning it will ever need.
Smudges of paint on the white border are best left alone until everything is dry, then covered with a little white or trimmed off if you plan to frame with a mat.
Varnish, and whether you need it
Varnish is optional. What it actually does is even out the sheen, because paint by number colors dry to noticeably different finishes and the patchiness is visible in raking light. It also gives you a surface you can dust without touching the paint.
Pick one made for acrylics. The three finishes do what their names suggest: gloss is bright and reflective, matte is flat, satin sits between them. Matte is the safe choice for anything hanging opposite a window, because gloss on a lit wall shows every reflection.
Applying it:
- Lay the canvas flat, not upright, so the varnish does not run.
- Work in a dust-free spot. Anything airborne lands in a wet coat and stays there.
- Thin coats. Two or three thin ones beat a single heavy one, which can go cloudy.
- Brush in one direction across the whole surface, then stop. Going back over a half-set area is what causes streaks.
- Let each coat dry fully before the next.
- If you are using a spray varnish, do it outdoors or by an open window. Sprays are the one part of this with real fumes.
Framing, honestly
What you can do depends on which kit you have.
A framed kit arrived already mounted on a wooden frame. Nothing more is needed. Hang it, or stand it on the easel included with the framed sizes.
An unframed rolled canvas needs more thought, and here is the part that usually gets glossed over: paint by number canvases are typically trimmed close to the printed image, leaving little or no spare material. Stretching a canvas over wooden bars requires several inches of blank margin to wrap and staple. Most rolled paint by number canvases do not have it, and pulling one over bars anyway will drag the printed edge around the corner or tear it.
Realistic options for an unframed canvas:
- Mount it flat to a rigid board with acid-free adhesive, then put the board in an ordinary frame. Simplest and cheapest.
- Frame it flat behind a mat, which hides the trimmed edge and is reversible.
- Take it to a framer and let them see the actual margins before deciding. Any competent framer will tell you in thirty seconds whether stretching is possible.
Whichever you choose, avoid anything that punctures the painted area. There is a fuller walkthrough in the framing guide.
On frame choice, the usual advice applies and it is not complicated: pick something that does not compete with the picture. A plain wood frame suits a landscape or a wildlife scene; leave the ornate gold for oil portraits. If the painting is going into a room you already like, match the wood already in it.
Where to hang it
Two things fade a painting: ultraviolet light and heat. Direct sun through a window will lift the color out of acrylic over a few years, and reds go first.
Hang it on a wall the sun does not reach directly. If the only wall available is a bright one, glazing with UV-filtering acrylic or glass is worth the extra cost. Avoid above a radiator or a working fireplace, and avoid bathrooms, where the humidity swing will eventually lift the paint off the canvas.
Storing a canvas you are not hanging yet
Flat is best, if you have somewhere flat and dry to put it.
If it has to be rolled, roll it with the painted side facing outward, around the widest tube you have. This matters more than it sounds. Rolling paint-side-in compresses the paint layer against itself and is what cracks it; rolling it outward puts that layer in gentle tension instead. Interleave with acid-free tissue, roll loosely, and do not compress the roll to fit a smaller tube.
Keep it somewhere cool, dry and dark. Not a loft, which cycles between hot and freezing, and not a basement or garage floor. A cupboard in the house is better than any of them.
Common questions
How long before I can varnish?
Several days after the last brushstroke, longer if the paint went on thick or the room is humid. There is no advantage to rushing it and a real risk in doing so.
Can I varnish only part of it?
No. The whole point is an even sheen, and a partial coat is more visible than none.
The colors look duller than the reference print. Can I fix that?
Often, yes. A gloss or satin varnish deepens colors noticeably, which is the most common reason people are glad they varnished.
Can I still touch up a section after varnishing?
You can paint over varnish, but the repair will sit at a different sheen until you varnish again. Do the touch-ups first.
I ran out of a color before finishing.
Each stock design has a matching set in the extra paint collection, which exists precisely because the big background colors run out.
