When it comes to creating hard edges in acrylic painting, a roll of masking tape can prove invaluable. Hard-edged geometric abstraction often relies on the precision that a masked edge can give you, and a strong straight edge in an area of a painting can set off more painterly passages within a composition. If you’ve tried using masking tape, had paint seep under it and given up because it didn’t seem to work – here is a technique that might solve the problems you were having and make the method work for you.
How to Paint Hard Edges Using Masking Tape
Seal the edge of the tape
On a very smooth surface fluid paint often seeps under the edge of masking tape but on a textured surface like canvas it is even harder to get the tape to attach completely along the edge. You can’t always see the leaks until you remove the tape and then you might spend quite some time wiping away wet paint or painting over dried leaks of paint. The key is to get the tape to create a smooth solid barrier along the edge.
One good way to keep the paint from seeping under the tape is to paint a thin layer of clear acrylic over the edge of the tape, wait until it is dry, then paint on your acrylic colour and pull away the masking tape. This removes the colour over the top of the tape as well as tears away the very thin layer of clear acrylic along the tape line. So you have a perfect edge.
I have tried a few different things and found the best combination is using these 3 steps:
1. Brush 2 coats of a clear fluid acrylic medium such as GAC 500 onto the edge of your masking tape, along the edge that will be the hard edge of your painted design. Let dry to the touch between coats.
2. The tape will get wet and some react by wrinkling, so the next step is essential – finger burnishing. Burnish down the wet tape with your finger. Do this for both applications of the GAC 500 – run your finger along the edge of the wet tape to press down all the wavy edges that appear when the tape reacts to the water in the medium, until it lies flat. When you are happy that your tape is lying flat to your canvas and the edge has a thin seal, let it dry.
3. Paint your colour in your taped shape area and remove the tape as soon as you are done, before the paint is dry. If the paint dries it forms a bond with the edge of the tape and I find when removing the tape the tape tears and leaves a thin piece of tape stuck to the paint that is difficult to remove.
Use low-tack masking tape
If you are layering hard edge shapes, and need to apply tape on top of paint as you build up layers, it will be necessary to use low-tack tape to be sure to not disturb your previous paint layers. Regular masking tape can remove your earlier acrylic paint and I have had it even pull off chunks of the gesso on a gesso panel (see image below). If low-tack tape is not available, or (as is sometimes the case) the low tack tape you have is still a bit too sticky you can remove some of the stick from your tape by sticking it to a clean table top, peeling it up and doing that a few times; this will reduce its adhesive qualities. It doesn’t need to be super-sticky anyway since you are sealing the edge.
Some tapes will wrinkle up more than others when they get wet. Our yellow tape is a good choice for this because it reacts very little to water and is very low-tack.
Try it a few ways
You will find this works differently if you are using a different surface or tape. As always I recommend experimenting to find what works best for what you are trying to accomplish and the materials you are using.
The sealing method would work for oil painting if doing a single layer so you are sealing the tape on canvas, not on an earlier layer of oil paint. This is because you wouldn’t want to paint acrylic medium on top of oil paint, but you can paint the oil paint on top of dried acrylic medium. You could experiment with a fast drying oil medium to seal the edge, but it would need to dry clear, and would take several days to sufficiently dry.
Creating accurate but not hard edges in acrylic or oil painting using masking tape
If you are not looking for a hard edge but a more-or-less straight edge then masking tape can still be useful. Instead of sealing it and using it as a stencil you can hand paint your acrylic or oil up to the edge and not over. By using it as a guide in this way you get a pretty straight line but it still looks hand-painted. A bit like painting up to a pencil line but without needing to erase anything. Of course the traditional way of achieving as straight a line as possible in your painting is with the use of a Mahl stick, which gives your painting hand something to rest upon allowing for a greater degree of control and precision when painting edges.
Great article! I never thought of sealing the tape with a
medium. Something else that you can do instead of tape is
use a ruler and run your paintbrush down it like you would a
pencil. It takes a little practice, and you have to be sure to
keep consistent pressure along the ruler, but it can make
some great results and skip the tape. Here is a painting that I
did using my ruler method:
This is great, but
I started using GAC 500 as I was mixing
up very small amounts of a heavy body
acrylic to match the color UNDER the
paint the paint, NOT the color I was
about to paint. I still think this is the
best simply because when GAC500
seeps out, it will leave a very slight gloss
edge when it dries. I have found that
letting GAC dry out considerably is much
better as I then a acts much more like a
heavy body paint…. what would be ideal
would be a proper heavy body clear
acrylic made solely for sealing paint
Interesting ideas, thanks Christopher.
What a wonderfully simple yet effective
method. I’ve spent years agonising over the
use of masking tape for this purpose and yet
te solution is very easy. Thank you for this.
So glad this is of use!
Hi, would like to paint a 1″ wide 2 4″ long strip on the side of my
Motor home doors, what would be the best masking tape for the
best results thanks.
I only know what I have read because I have never painted a vehicle. So I can only give you some general ideas.
It sounds like you might want to think of this as a pinstriping project.
So all you would need is a pinstriping tape and a pinstriping enamel paint. The enamels have a built-in sealant as they contain varnish, so they are very durable.
Here are 3 good pinstriping enamels
Here are our pinstriping tapes (rub the edges down well)
I hope that helps!
Hi, I’m doing a geometric painting.
some days the tape doesn’t stick to the acrylic paint to do the next step. I assume is the humidity. My air conditioning is running. What can I do? Thanks, Beatriz
I haven’t experienced this. But if it is humidity then perhaps a heat gun, hair drier or even a fan might work to dry it off.
If you can get the tape to stick enough to paint over the edge with the clear medium, then that should work.
I want to create a hard edge on an oil
painting and have found the task
challenging. The article writes I can use a
“fast drying oil medium to seal the edge”. Are
there any particular mediums you would
You will need to experiment.
First try whichever fast-drying medium you already add to your paint, if you use one.
Here is a long to the fast-drying mediums on our website.
If you don’t use one this might be a good place to learn a bit about them.
HANNAH IVORY BAKER COMPARES FAST DRYING MEDIUMS
I am trying to sponge around a cut out
letter on a plain white canvas. What will
adhere the letter to the canvas so my
granddaughter can sponge around it?
Most people use a temporary adhesive stencil spray. We don’t sell it I’m afraid. I’ve heard hairspray works, a light coat then wait until it gets tacky. But, I’ve never tried it so can’t recommend it.
Hope that helps.
I’ve been trying to use 1/8” low tack tape
on my canvas, but I’ve found difficulty
getting the tape to stick onto the canvas
(no problems with wider tapes). Any
Have you tried the method described in the article? It will work even if the tape isn’t sticking. Just do both steps and repeat again.
Let me know how you get on.