Almost every mistake in a paint by number is fixed the same way: let it dry, then paint the correct color over the top. Acrylic is opaque and forgiving, and covering a mistake works better than removing one. The single thing that will genuinely ruin a canvas is reaching for something to strip the paint off with.
Start here: is the paint wet or dry?
This determines everything.
Wet means the last minute or two. Acrylic is touch-dry astonishingly fast, and the window for wiping something away is much shorter than people expect.
Dry means anything beyond that. Once it is dry, stop trying to remove it and start thinking about covering it.
The wet fix: wipe it, immediately
Paint gone into the wrong section, or over a line, and still glistening: take a cotton swab or the corner of a damp cloth and lift it off with one gentle stroke. One stroke. Scrubbing spreads it into the weave and pushes it further into the section you were trying to protect.
Then let the area dry completely before repainting it. Painting onto a damp patch gives you a thin, streaky coat that will need doing again anyway.
The dry fixes
Wrong color in a section
Paint the correct color straight over it. One coat if the correct color is darker than the mistake, two thin coats if it is lighter. Let the first dry fully before the second.
Do not lay down white first as a base. It is a common suggestion and it is a poor one: white under a color shifts the final hue, it adds a third layer of thickness, and on many designs white is a numbered color you will want later.
Paint over a line, into the next section
Wait until everything is dry, then re-cut the edge. Load a fine brush lightly with the color that belongs on the invaded side and draw it along the line, pushing the boundary back where it should be.
Pull the brush along the line rather than pushing into it, and turn the canvas so the stroke always comes toward you. A slightly dry brush cuts a cleaner edge on a straight run than a fully loaded one.
A repaired edge is invisible from arm's length, which is the only distance anyone will ever look at the painting from.
A ridge or blob of thick paint
Only worth addressing if it catches the light. Wait until the paint has fully cured, which means days rather than hours, then knock the high point back with a very light touch of fine sandpaper, and repaint that section thinly. Test your pressure on the white border first.
If in doubt, leave it. A slight texture reads as brushwork. A hole sanded through to the canvas does not.
A section you missed entirely
Common, and usually only spotted when the canvas is nearly finished. Hold the reference print beside the canvas and compare region by region rather than hunting across the whole thing. Photographing the canvas with your phone and looking at it on screen also makes gaps jump out in a way they do not in person.
A number you cannot read
Not a mistake yet, and worth stopping to solve rather than guessing. Move the lamp so the light rakes across from the side, which throws the printed digit into relief. Failing that, photograph the section and zoom in, or find the same area on the 11x17 reference print and match the color from there.
Guessing is how the wrong color ends up in a large area.
Paint on the white border
Leave it alone until the canvas is finished. Then either cover it with white or simply ignore it, because a frame or a mat will hide the border entirely.
What not to use, ever
This is the part worth memorizing, because these suggestions circulate widely and every one of them does permanent damage.
- Rubbing alcohol. It softens and dissolves cured acrylic. It will take your painting off, and it will not stop at the part you wanted gone.
- Paint remover or stripper of any kind. Formulated to destroy exactly this kind of coating.
- Acetone or nail polish remover. Same problem, faster.
- Turpentine or white spirit. Solvents for oil paint, and no help at all with acrylic beyond wrecking the canvas primer.
- Aggressive scraping with a knife or palette knife. The printed lines and numbers are ink on the primed surface. Scrape the paint off and you take the design with it, and then the section is genuinely unrecoverable.
There is no product that removes dried acrylic from a paint by number canvas and leaves the printed design intact. Covering is the answer.
Preventing the common ones
- One pot open at a time. Most wrong-color mistakes are two open pots and a moment of inattention.
- Finish a color before starting the next. Work one number right across the canvas. It makes a mix-up close to impossible and cuts the number of brush washes.
- Light from the side. A daylight bulb positioned so your hand does not shadow the section. Poor light causes more errors than an unsteady hand does.
- Never paint against a wet edge. Two touching sections painted while both are wet will creep into each other. Skip to a section elsewhere and come back.
- Rest your forearm, not your fingers. Anchoring your little finger on the canvas works only on paint that is fully dry. On anything recent it is how a print of your fingertip ends up in the sky.
- Stop when you get tired. Almost every ruined section happens in the last twenty minutes of a long evening.
Sealing, afterward
Once the canvas is finished and has cured for several days, a clear acrylic varnish evens out the sheen between colors, which also does a good job of disguising repaired areas. Repairs sit at a slightly different finish to their surroundings until everything is varnished together. Details are in the canvas care guide.
Common questions
I used a whole pot on the wrong section. Can I get more?
Yes. Each stock design has a matching set in the extra paint collection. On a custom canvas the paints are mixed for your image, so the spare sets are added at checkout rather than reordered later.
Can I just leave the mistake?
Often, yes, and it is worth asking honestly. Step back six feet before deciding. A great many things that look glaring at nose distance are entirely invisible at the distance the painting will actually hang.
The paint will not cover the printed number.
That is a pale color over a dark digit, and it is normal rather than a mistake. Let the first coat dry completely, then lay a second thin coat. Two thin coats cover better than one thick one and leave a flatter surface.
I tore the canvas.
A small tear in the border does not matter and will sit under the frame. A tear in the image can be backed with a patch of acid-free tape on the reverse, then painted over on the front once it is flat. It will not be invisible, but it will be far less noticeable than the tear.
My colors have gone muddy.
Almost always cloudy rinse water carrying gray into every subsequent pot. Two jars, one for the first rinse and one for the last, and change them when they discolor.
