Murals 101: How to Paint a Perfectly Straight Line
For someone who paints murals, a blog post about how to paint a straight line might seem a little… strange. Painting a straight line is like, painting 101, right? We muralists do it all the time. But after painting in public places for as long as I have, I know that to the average person, this isn’t actually so easy. I’ve lost track of how many times a passerby has commented “I can’t even draw a straight line!”
Whether you are a professional muralist and artist, or someone who is just learning the ropes, knowing how to execute the basics is key to a polished final product. Depending on what your design looks like, whether you're working on geometric patterns, architectural elements, or just need a sharp division between colors, getting that line right is crucial!
Thankfully, I’ve painted enough murals at this point to have figured out a few straight line hacks to share with you. In this guide, we'll cover my top tips you need to know about painting straight lines, from using painter’s tape properly to utilizing levels - plus a few other tricks that just seem to work.
1. Marking Your Line: Chalk, Tape, or Laser?
I’ve found that good prep work makes a world of a difference when it comes to how smoothly a mural installation goes. Before any painting begins, you need a clear guide for where your line(s) will go.
Here are three tried and true methods for marking your *straight* lines:
Chalk Line
This one is simple, and classic. A chalk line is a device that is extremely useful for marking long, straight lines on a wall (this is my favorite one!).
Here’s how to use one:
Hold the chalk line taut between two points.
Snap it against the wall, leaving a fine chalk guideline. ( Note: There are different colors of chalk powders you can purchase. In my experience, blue is the easiest to paint over (vs. black which can get a little messy at times).
Paint over the chalk line or use it as a guide for taping.
Manual or Laser Level
For max precision, your classic manual level (like a bubble level or spirit level, or whatever your dad has in his toolbox, honestly) works great for shorter lines, but for long, uninterrupted lines, a laser level is going to be your best bet.
Position the laser at the desired height and turn it on to project a bright, straight line across your work area. Usually best accomplished in a lower light!
Use this guide to apply tape or paint directly along the beam.
If you're working outdoors, a chalk line or a manual level might be more practical since laser beams can be hard to see in bright daylight.
2. Using Frog Tape for Clean, Sharp Lines
If you don’t fully trust yourself to paint along a guide by hand, Frog Tape is a game-changer. There are many types of painter’s tape out there, but I’ve tried them all and can confidently say don’t bother wasting your time with any other kind! It’s specifically designed to prevent paint from bleeding under the edges (which has always been an issue for me with other painter’s tapes), but there are a few tricks to using it effectively.
How to Apply Frog Tape Properly:
Press It Down Firmly: Once you've placed your tape along your guide line, go over it with a credit card (this works better than anything!) or a putty knife to ensure there are no air bubbles. This makes sure paint won't seep underneath.
Dampen the Tape: Run a slightly damp towel over the tape before painting. This activates the tape’s adhesive, helping it to seal against the wall even better.
Layering the Background First:
First, paint the background color up to the tape line and let it dry.
Then, paint your second color over the top.
If any paint bleeds under the tape, it will be the background color first, creating a perfect seal.
3. Painting Along the Tape Line
Now that you’ve got your tape applied correctly, the next thing to focus on is ensuring your line comes out nice and Diet Coke crisp:
Use a Dry Brush Technique: If you overload your brush or roller with too much paint, you increase the chance of it seeping under the tape. Instead, use thin, controlled layers. I’d rather take the time upfront to let multiple layers of thin paint dry, then have to spend time touching up seeped paint.
Paint Up and Away From the Tape: Brush or roll away from the edge of the tape instead of pushing paint towards it, which can force it underneath.
Remove the Tape While the Paint is Wet: As soon as your second color is applied, carefully peel off the tape while the paint is still wet. It might sound counterintuitive to what you’ve been told, but this prevents dry paint from peeling up with the tape.
4. Fixing Mistakes and Touch-Ups
Even with the best techniques, sometimes there’s still going to be some bleeding or unevenness here and there. I’ve got tricks for that, too:
Use a small angled brush and carefully go over any areas where the paint has bled under the tape.
If the edge isn’t crisp enough, use a fine-tipped paint marker to touch up small details.
You can also find “touch-up” brushes (like these!) that make getting precise with your touch ups a lot easier
Finally, a steady hand and patience are key— don’t rush and take your time with touch ups. It’s always worth it for the end result.
Crispy Lines >
Painting a straight line might seem simple, but really mastering the technique takes practice, patience, and the right tools. Whether you’re using a chalk line, a laser level, or just relying on Frog Tape and careful technique, you can definitely achieve clean, sharp lines every time - and both your clients and your mental health will thank you for it! Never underestimate how much more polished and professional a well executed straight line can make your mural look.