How to Apply Masking Fluid with a Ruling Pen

How to Apply Masking Fluid with a Ruling Pen for Precision in Watercolor Painting
Masking fluid is a versatile tool for preserving white spaces or creating sharp-edged highlights in watercolor paintings. When paired with a ruling pen—a tool traditionally used for drafting—it becomes a powerful instrument for achieving crisp, controlled lines. Here’s a guide to mastering this technique:

Materials You’ll Need

Masking fluid (e.g., JOFOOK, Winsor & Newton, Pebeo)
Ruling pen (adjustable for line thickness)
Watercolor paper (stretched or heavy-weight)
Soapy water or masking fluid applicator cleaner
Soft eraser or masking fluid remover
Tissue paper or cotton swabs

Step-by-Step Process

1.Prepare Your Tools
Clean the ruling pen: Dip the nib in soapy water and wipe it dry to prevent masking fluid from sticking.
Shake the masking fluid: Ensure it’s well-mixed but avoid creating bubbles.

2.Adjust the Ruling Pen
Use the screw on the pen to set your desired line width. Test on scrap paper first.
Pro tip: Thinner lines work for details; wider lines suit bold shapes.

3.Apply the Masking Fluid
Load the pen by dipping the nib halfway into the fluid. Wipe excess on the bottle’s edge.
Hold the pen at a 45° angle and glide it smoothly across the paper. Avoid pressing too hard to prevent bleeding.
For curves, rotate the paper instead of bending the pen.

4.Let It Dry
Allow the fluid to dry completely (10–15 minutes). Do not use a hairdryer, as heat may bond it to the paper.

5.Paint Over the Masked Areas
Proceed with watercolor washes. The masking fluid will resist the paint, protecting the covered sections.

6.Remove the Masking Fluid
Once the paint is dry, gently rub the masked areas with a soft eraser or your fingertip.
Caution: Pull slowly to avoid tearing delicate paper.

Tips for Success
Work in layers: Apply masking fluid in stages for complex compositions.
Avoid clogging: Clean the ruling pen immediately after use with soapy water.
Test first: Some masking fluids stain paper—always do a patch test.

Why Use a Ruling Pen?
Unlike brushes, ruling pens prevent frayed edges and offer unmatched precision for geometric designs, architectural details, or fine textures. With practice, this tool elevates the professionalism of your watercolor work.

Conclusion
Mastering the ruling pen and masking fluid takes patience, but the results—razor-sharp highlights and intricate patterns—are worth the effort. Experiment with line weights and compositions to unlock new creative possibilities in your artwork.