A Step-by-Step Guide for Watercolour Artists

As watercolour artists, one of the most critical steps in our creative process is transferring our initial sketches to watercolour paper. This is where precision matters, as the foundation of your painting depends on the accuracy of your sketch.

One of the tried-and-true methods for achieving this accuracy is the grid system. In fact, the grid system has been used by artists for centuries, with some of the earliest documented use dating back to ancient Egypt and Greece. Renaissance masters like Leonardo da Vinci and Albrecht Dürer relied on this technique to achieve precise proportions and perspective in their drawings and paintings. While it might seem a bit tedious at first, trust me, the results are worth it.

In this post, I’ll walk you through the grid method step by step, breaking it down into easy-to-follow instructions. Whether you’re transferring a complex composition or a simple subject, the drawing grid system ensures that your sketch will be perfectly proportioned on your watercolour paper — and you don't even need to have excellent drawing skills!

What You’ll Need

Before we dive in, let’s gather our materials:

• Original Sketch or Reference Photo: This can be a drawing, photograph, or any reference material you plan to transfer.

• Ruler: A clear, acrylic ruler is ideal for measuring and drawing your grid lines.

• Pencil: A 2H pencil works well because it creates light marks that are easy to erase.

• Eraser: A kneaded eraser is best as it can lift graphite without damaging your paper.

• Watercolour Paper: Your chosen drawing paper, ready for the transfer.

• Lightbox or Window (Optional): Helpful if you want to ensure your grid lines are very faint.

• Grid Drawing Tool or Grid Drawing Utility Program (Optional): There are digital tools and apps available that can overlay grids on your reference photo, making it easier to work with grid labels and customisable grids. These tools often allow you to adjust the grid size, grid colour, and even the aspect ratio.

Step 1: Create a Grid on Your Reference Photo

Start by deciding the size of your grid squares. Typically, a 1-inch grid is standard, but you can adjust the size depending on the level of detail in your reference photo and the size of your paper.

Mark the Edges: On your original sketch or reference photo, use your ruler to mark out points along each edge of the paper. Make these marks every inch (or whatever measurement you’ve chosen for your grid squares). The number of rows and columns will depend on the dimensions of your image.

Draw the Grid: Connect the marks with straight lines, running both horizontally and vertically across the entire surface of your sketch.

Some artists also use diagonal lines to help maintain proportional accuracy when transferring more complex images.

Step 2: Create a Matching Grid on Your Watercolour Paper

Next, you’ll replicate the grid on your watercolour paper.

Measure and Mark: Just like you did on your reference image, measure, and mark points along each edge of your watercolour paper, ensuring they match the size and spacing of the grid on your sketch. Make sure the aspect ratio of your grid matches the same ratio of your reference photo. You will need the same number of squares that you have on your reference image.

Draw the Grid: Connect the dots to form your grid on the watercolour paper. Keep these lines as light as possible since you’ll erase them later. A 2H pencil is perfect for this because it leaves fine, light marks that won’t damage your watercolour paper.

Step 3: Transfer the Sketch

Now comes the exciting part - transferring your sketch to the watercolour paper.

Focus on Each Square: Look at the first square on your original sketch. Carefully copy what you see in that square onto the corresponding square on your watercolour paper. This method breaks down complex images into manageable sections, making it easier to achieve accuracy.

Take Your Time: Work square by square, transferring the lines and shapes from your sketch to your watercolour paper. Don’t rush this step. The grid system’s beauty lies in its precision, so take your time to ensure each section is correctly transferred.

Check Your Work: Periodically step back and look at your work as a whole. Ensure that the transferred image is consistent with your original sketch and that you transferred the entire image.

Step 4: Final Touches and Erasing the Grid Lines

Final Touches: You might want to refine certain areas of your sketch before you begin painting.

Once your sketch is fully transferred, it’s time to erase the lines.

Lightly Erase: Use an eraser to gently lift the grid lines from your watercolour paper. Be careful not to smudge your transferred sketch. If your grid lines were light, they should erase easily, leaving your transferred sketch intact and ready for painting.

Additional Tips and Considerations

Choosing the Right Grid Size

Detail vs. Simplicity: Smaller grid squares (e.g., ½ inch) are better for highly detailed sketches, while larger squares (e.g., 1 inch (2.54 cm) or more) are suitable for simpler designs.

Scaling Up or Down: If you want to enlarge or reduce the size of the sketch, adjust the grid size on the watercolour paper accordingly. For example, doubling the grid size on your watercolour paper will double the size of your transferred sketch.

Dealing with Complex Images

For intricate details, focus on one small section at a time and simplify the forms within each grid square. This approach helps maintain accuracy without overwhelming you with the complexity of the overall image.

Maintaining Paper Quality

Drawing lightly is crucial to avoid damaging the watercolour paper, which is more sensitive to erasure than regular drawing paper. This ensures that the surface remains intact and ready for paint.

If you're planning to stretch your watercolour paper, make sure to do it before applying the grid. I've found that soaking the paper in water can make any graphite marks harder to erase later.

Alternatives to the Grid System

Comparing Techniques

While the grid drawing technique is fantastic for precision, you might also consider other methods like lightbox tracing or using transfer paper, depending on your specific needs. I have written an individual blog post about transferring a sketch onto watercolour paper.

Each method has its advantages - lightbox tracing is quicker, while transfer paper is convenient for delicate work.

Use Ordinary Drawing Paper

If you prefer not to draw directly on your watercolour paper, you can use this method: use the grid system to draw your sketch on a separate sheet of drawing paper that’s the same size as your watercolour paper. Once you’ve finished, you have two options: you can trace your sketch onto tracing paper to create a line drawing for transfer, or you can transfer the drawing directly onto your watercolour paper using one of the transfer methods described in this blog post.

I like to transfer the drawing onto tracing paper so I can refine it further.

Common Mistakes to Avoid

Inconsistent Grid Lines

Ensure that the number of squares on your reference image grid matches the number of squares on your drawing grid to maintain accurate proportions.

Smudging

To avoid smudging, consider placing a piece of clean paper under your hand as you draw, especially if your original sketch is detailed and prone to smudging.

Additional Tools and Technology for the Grid System

With the advent of technology, many artists now use digital tools to enhance their grid drawing experience. Grid drawing apps allow you to upload your reference photo and overlay a grid directly onto the image. You can adjust the colour and opacity of the grid lines, and even customize the grid size and number of rows and columns. Some apps offer additional features like sketching filters or the ability to zoom in on the image for detailed work.

These digital tools can be particularly useful for advanced artists looking to save time or achieve greater precision. Additionally, they allow you to save your grids and sketches, making it easy to return to your work later without having to recreate the grid from scratch. When using digital tools, always ensure that the aspect ratio of your grid matches the original image to maintain proportional accuracy.

Keep Practicing and Perfecting Your Grid Method Skills

The grid system is an invaluable tool for artists of all levels, providing a methodical way to transfer sketches accurately to watercolour paper. While it may take a bit of time to set up, the precision and consistency it offers make it worth the effort, especially for complex compositions.

Remember, like any technique, mastering the grid system takes practice. I encourage you to try it out on a few sketches before applying it to a final piece. The more you use it, the more intuitive it will become.

Finally, I’d love to hear about your experiences with the grid system. Have you tried it before? Do you have any tips or tricks that make the process easier? Share your thoughts in the comments below, and happy painting!

If you are interested in learning to paint in watercolour, I have over 200 online, voiced over watercolour tutorials for all skill levels.

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