How to Watercolor a Pencil Drawing Without Leaving Marks


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Sketching out a painting before putting brush to paper is a must-have for many of us artists. Those pencil lines can be so helpful in making sure that a painting turns out the way we want it too. But, with watercolor, they can also be a problem. Given the light washes used in watercolor, it can be hard to hide pencil lines that you don’t want to appear in your finished work. 

In order to watercolor a pencil drawing, it’s best to start with a sketch on a separate piece of paper. Then, use a light box to transfer the sketch to your watercolor paper with either with very light lines from a hard pencil or the watercolor paint itself. 

Watercoloring over a pencil drawing isn’t easy, but there are some key techniques you can use to make sure that your pencil lines are hidden in your finished piece.

Start with a Separate Sketch of Your Watercolor Drawing

I don’t know about you, but my first attempts at a sketch are always a mess. I erase, scribble, and screw up more times than I plan for. No matter what I do, my brain needs some time to get out all of the creative mess that’s inside of it before I can get to my polished, finished work. 

For acrylics, this is no problem. A good, heavy coat of acrylic will cover even my messiest sketches. But, with watercolor, I have to be more careful. Even if I plan to do a vibrant layer of watercolor that will cover my pencil lines, I don’t want any indents in the paper or imperfections that might be able to show through the lighter areas of the painting.

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It’s just not worth the risk. Why work so hard on a painting just to find a heavy line poking through somewhere that you don’t want it to?

For watercolor, I have a hard rule to always start with a separate sketch. It doesn’t have to be elaborate or time-consuming, but spending even 15 minutes separately sketching out what you want to put on your watercolor paper can be the difference between a clean finished piece of work and one where pencil lines are showing through. 

Use a Light Box to Transfer Your Sketch to Your Watercolor Paper

When I was a kid, I was always holding my papers up against the windows to make my own light box. It was great, but windows aren’t designed for art and this technique ended up having its limitations. One of those limitations is working with watercolor paper.

Watercolor paper is thick and needs more than the light shining through a window to make it see through. The good news is that there are some cheap light boxes that are actually really good. I bought this one for about $20, which is a steal given how much I use it. At this price, if you only use your light box for your watercolor pieces, it’ll be worth it. I bet you’ll find more uses for it than that though. 

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If you only have a window at your disposal, you can use that method if needed. A light box is easier, but good old fashioned windows will also get the job done.

There are two ways I suggest using a light box or window to transfer your sketch to your watercolor paper: 

1) Watercolor Right onto the Paper on the Light Box…Carefully

If you really want to avoid having any little pencil marks showing through your watercolor, get rid of your pencil all together. Instead of transferring your sketch onto your watercolor paper with your pencil, do a very basic and light first wash with your watercolor right on the light box. 

The huge benefit with this technique is that you won’t risk having pencil lines on your paper. There is no pencil involved in the first place! The huge downside to this technique is that water and electronics don’t mix very well. Be sure that your first wash is very light and fairly dry. You don’t want water seeping through your paper into your light box.

Great Ways to Use a Light Box for Tracing
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If you choose this technique, keep your wash so light that you can barely see it. The purpose of this wash is to simply know where your lines and shapes are supposed to be, not to add significant body to your piece of work. Apply only as much paint as you need to in order to gain a basic map of where everything is supposed to go.

This technique works best for watercolor works that have large shapes and outlines. If you have too many details, it’ll be hard to map out everything you need to in just a light wash. In the end, you could end up with too many heavy lines that look cartoonish or clunky shapes that do a disservice to your original drawing.

Key takeaway: To transfer a pencil drawing to watercolor paper using a light box, use a very light and fairly dry wash to map out big shapes and significant lines. Do not focus on details and only apply as much paint as you need to understand the outline of your design.


2) Lightly Map Out Your Sketch

Yes, it’s completely possible to sketch out your drawing on your watercolor paper without falling in the trap of having all of your pencil lines show through when you’re done. Start off with making an initial sketch on a regular piece of paper that you’ll then transfer to your watercolor paper.

IMPORTANT: make sure that you start with this initial sketch. DON’T skip it. It’s really tempting to go straight to the watercolor paper, but don’t do it. 

No matter how good you are, you’ll probably need to erase and rework parts on your initial sketch. No doubt, you’ll end up pushing too hard with your pencil at times and leave marks that you can’t erase. It’ll happen, trust me. Don’t take a risk of having pencil lines showing through your final result. Start off with an initial sketch and take the 5 extra minutes to transfer it to your watercolor paper afterwards.

Also, if you’re worrying so much about making your initial sketch right onto your watercolor paper without pushing too hard with your pencil and leaving eraser marks, you’ll probably limit your creativity. Your brain will be focusing so hard on staying light and airy that it won’t be focusing on the art of your sketch. When you make a separate initial sketch, you can be messy, creative, and imperfect. This freedom will result in a better end result than if you tried to be 100% right onto your watercolor paper. 

Once you’re finished with your initial sketch, use a light box or window to transfer it onto your watercolor paper. As you transfer the drawing, use a hard pencil like a 4H pencil that leaves light lines. 

As you’ll see, nowhere in these suggestions do we talk about using heavy pencil lines on your watercolor paper. Nope, that will never serve you well. With watercolor paper, we ALWAYS want to limit the amount of pencil lines that we’re putting down. Make sure that you have a hard pencil or mechanical pencil that lets you leave the lightest lines possible. This is not the time to bring out those creamy pencils. 

Do the best that you can to have an easy touch without pushing hard on the paper. Also, consider eliminating any lines that aren’t necessary. You’ll have your initial sketch as a reference as you work, so you don’t need to be extremely detailed with the sketch you transfer on to your watercolor paper. 

Erase As You Go

Once you’ve transferred your sketch onto your watercolor paper, it’s time to start painting. So, if you used option #2, what are you supposed to do about those pencil lines? Even if they’re light and faint, maybe you’re still worried that they’ll show through.

So, if you’ve lightly drawn your sketch on your watercolor paper and you’re still worried that your light lines will show through, try erasing them as you go. Since you’ll have your initial sketch as reference, you won’t have to worry too much about forgetting what was there. That said, don’t erase so much that you get lost.

You’ll want to be careful with how you erase. Always erase away from any areas that are still wet. Erase slowly and lightly so that you leave behind as few shavings as possible and don’t risk damaging the paper. As you brush the shavings away, go slowly and brush away from any wet areas. 

Make Your Pencil Marks a Part of Your Work

If you’re struggling to get rid of your pencil marks when making your watercolor art, embrace them and turn them into a part of your art. Use some Micron pens and make a beautiful outline for your watercolor painting that adds character to your work.

Should You Outline a Watercolor Painting?

Water coloring pencil drawings without leaving marks takes some practice. It’ll also vary depending on how light or dark you plan for your water color paints to be. You may make some mistakes, but that’s ok. Art was never meant to be perfect and every mistake you make expands your knowledge for the next time. Don’t stress too much about it and just get painting. 

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Diana Fitts

Diana has been an artist for over 25 years and has training in drawing, painting, digital drawing and graphic design. Diana's latest obsession is digitally drawing with Procreate and creating t-shirt designs with Canva. Diana has experience selling her art across a number of platforms and loves helping other artists learn how to make money from their art as well.

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