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Common Acrylic Painting Mistakes and How to Fix Them

Acrylics are more forgiving than water color, but definitely less than oil. But you can correct mistakes, even if the mistake is as fundamental as the wrong background color. Contrary to popular belief, an acrylic painting can be corrected even if it is completely dry. Get off on the right foot with a few words of wisdom: Acrylic Painting for Beginners Step by Step. Oftentimes there are several ways to fix a mistake and it is important to consider your options before you go ahead so as not to make things worse or damage your canvas. Thick layers of paint, thin layers of paint, dry or wet; below I will not only show you how to fix your mistakes but also how to think about each solution so you can choose the most appropriate one.

I Picked up the Wrong Color by Mistake!

You are part way through your painting and while looking at the canvas you expertly reload your brush with that beautiful Phatalo Green, only it turns out to be Alzarin Crimson and presently you have a murky streak of red/black/green on your canvas, that you did not plan for. You have done a dip dab! You scream and look in disbelief back and forth between your palette and your painting.

Your instinct, if it is anything like mine, is to look for the palette knife and scrape the mess off. Stop! Don’t use your palete knife for this. Instead use your palette knife skills for some abstract art with this guide: Abstract Magic: Pallet Knife Painting.

If it was, for example, yellow on white this would be the right thing to do. But with dark saturated colors there may be better options I’ll share below. Also if the dab of unwanted color has been placed at a point of detail in the painting and you are worried you may not be able to remove the wet paint without ruining the detail or spreading it too much, your best option would be to let it dry completely and remove it later.

Removing Dry Paint

To carefully remove the dried offending paint you can follow the steps below:

  1. Rub with a little denatured alcohol applied with a paper towel, folded as small or as big as you need. The alcohol will soften the paint and you can remove as much as you want, just the offending paint, down to the base paint, or all the way down to the canvas.
  2. If you want to repair with the correct color then sand the area lightly to create enough tooth for the paint to adhere to – a light grit sandpaper is all you need. It is a good idea to wear a mask while doing this as acrylics are basically plastic and sanding introduces very fine plastic dust particles into the air and you don’t want to inhale that.
  3. Having finished the sanding, use a damp cloth to wipe dust off the canvas.
  4. Once it is all dry you are ready to paint.

Sometimes I can still see a tiny bit of offending color. I don’t want to damage the canvas, but I am worried that it may show through if I just paint over. In that case I paint it over with a couple of very thin layers of Artists Grade titanium white.

This will literally white out any residue left of the offending color.

Removing Wet Paint

There is a different method for removing thick wet paint straight out of the tube or mixed with a thickening medium. Once on the canvas with other paints, it is hard to separate cleanly if the first layer of paint is not completely dry. If you are painting with heavily diluted paints, also called glaces, the first layer will often be dry enough that you can remove new paint immediately without significant damage to the previous layer.

Thick: If you decided to, or you were overtaken by the impulse to use the painting knife to remove the paint, I recommend you leave the area to dry completely. You may now be able to apply thin layers of artist grade titanium white to block out any remaining offending marks. I recommend artists  grade because in my experience, lesser quality paints will not cover well.

Thin: If your paint are thin layers and the layer you painted on earlier is dry or near dry, you will be able to remove the wet paint with water, with hardly any damage to your earlier painting. Simply grab a clean wet brush and a clean dry cloth or kitchen paper. Apply the wet brush to the offending paint and dab with kitchen towel/cloth, keep going until all the offending paint is gone – do make sure when you reapply the cloth/kitchen paper that it is clean.

Correcting Mistakes that Still Show Through

Your painting is finished and dry. While you were working on it earlier, you made a few mistakes along the way, you decided to leave them in but paint them over to hide them. You used artist grade Titanium White and painted it on in several thin layers, leaving each one to dry before you applied the other. It was perfect, only now a few days later the original paint is showing through in places.

Pro Solutions

First, I would try to correct the problem by applying a few more thin coats of Titanium White. Bear in mind that it takes longer to dry than other pigments and make sure it really is dry before you apply a new coat.

If the problem persists you can try applying an isolation coat and when that is dry another coat of Titanium White. This you should only do once you are completely happy with the rest of the painting. In effect, this is done when you deem the painting finished as the isolation coat will make the surface more slippery to paint on.

An isolation coat is most often used between your finished painting and the varnish, it is perfectly transparent. The idea is that it protects your paint from being damaged by solvent when the varnish is removed and reapplied every few years, keeping the colors looking fresh and new. The less traditional use is to use it as a barrier between your original painting and new painting on top, eliminating show through from previously corrected areas.

You can now buy an isolation coat pre-mixed, but if you have gel gloss you should just mix your own.

You will need artist quality gel gloss—all the professional brands have one to their name— and water, distilled water, if possible.

You need two part gel to one part water. If you have not used an isolation coat before or haven’t used varnish for a while, it’s advisable that you prepare yourself a couple of test pieces to practice on. It is not necessary to use a canvas or acrylic board for that; a couple of pieces of stiff card will do fine. Paint them in a dark color blue or brown to make it easier for you to see what you are doing.

Practice using different brushes, once you feel happy with your choice of brush and confident applying the isolation coat you need to work fast as it dries very quickly.

Once your isolation coat is dry, you can start applying thin layers of Titanium White or whatever color needed to cover the show through.

Reusing a Canvas After  a Painting Didn’t Work Out

Some times, however hard you try your paintings just don’t work out and all you want to do is start over again.

You can absolutely paint over it with several layers of artist quality paint or black or white Gesso for example. Just first decide whether it is worth the time and effort. Using Gesso to prep a canvas is a technique for many art styles, check out some common questions around the practice: Should I Gesso My Canvas or Surface Before Painting?

Reusing A Canvas Takes More Time Than You Think

Painting over a whole canvas is more tricky than painting out a small mistake. When you paint over a smaller mistake and it is done well, the rest of the painting largely distracts you away from any slight difference in texture thickness and color. However, painting over a whole canvas you need at least two layers of the highest quality paint or Gesso, possibly more if you have highly contrasting and/or dark colors to cover. As you are planning to start fresh you don’t want any difference in texture, color or thickness to distract you.

Reusing A Canvas Won’t Feel Like New

Because acrylics are plastic based, your build up layers create a hard and shiny surface. A repainted surface in acrylics will have lost a lot and in some cases all of its tooth, leaving a texture that is slippery. Or if you have painted over the whole canvas with white acrylics it can feel chalky. Either way, the paint is not pulling off the brush as it does on a new canvas. In short your painting experience will differ drastically and not in a good way.

Limitations of an Over-Painted Canvas

If you have over-painted a canvas you will have lost its absorbency and will no longer be able to use it for thin water color like techniques as the watery paint no longer will behave the same. Personally I have found very few instances where I have been able to use an over-painted canvas for anything other than a heavily textured or impasto painting with any kind of success.

Quick Tips on Fixing Acrylic Painting Mistakes

  1. Accidents and small mistakes can quite easily be remedied and if you are careful and patient no one will be any the wiser.
  2. If you are removing paint, there is a different method for dry, wet, thick, and thin applications.
  3. Always use artist grade paint for over-painting and rather use several thinner layers than one thick layer.
  4. Corrections still showing through, apply an isolation coat and paint again with artists grade Titanium White. Again use best quality and thin layers.
  5. Fixing the mistake may not always be the best way forward; acrylics is very forgiving medium, at the time of making mistakes this can be a disadvantage. Acrylics dry so fast and you can erase your mistake and be ready to paint again in a matter of minutes.

Should You Fix Your Mistake?

Painting in oil or watercolor, or working with collage, the chances of ruining the rest of the work trying to fix a mistake always makes me think twice before correcting it, and oftentimes I will end up incorporating the mistake rather than fixing it… I believe Bob Ross calls them happy accidents.

Not being forced to think about it too much before correcting a painting I believe can be a disadvantage.

As artists, we need space and time to look at and judge our work and make conscious choices.

Acrylics are so easy to correct that it often leads you to look less and paint more, the result can be a painting that is perhaps technically perfect but lacking in life and character.

When you next make a mistake–unless it is an obvious dip dab disaster– take a break; have a coffee or even take a walk. If when you look at it with fresh eyes you feel it isn’t a bad mistake but you can’t see the way to incorporate it into your painting at this time, put your painting away for a couple of days or even a week, if you are able and don’t have a deadline that won’t allow it.

You may be surprised at what you will find and, talking from experience, this practice will save you a lot of stress, money, materials and, surprisingly, time over the years.

Final Words

I hope you found the fix you were looking for and encouragement too. Even with many years of practice I still make mistakes; the dip dab more often than I would be willing to admit. But there are also times where no fix will make my paintings right and I have to start again.

Common Acrylic Painting Mistakes and How to Fix Them

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