What Is Lock Brush to View in GIMP?

The "Lock Brush to View" feature in GIMP is a brush tool setting that locks the size of your brush to the display screen rather than the canvas pixels. This article explains how this setting functions, how it alters traditional brush scaling, and why it is a critical asset when painting fine details on high-resolution canvases without constantly readjusting your brush size.

How "Lock Brush to View" Works

By default, GIMP anchors brush dimensions to the image's canvas pixels. If you set a brush to 50 pixels, it will always cover exactly 50 pixels of your image data. When you zoom in on a high-resolution canvas to work on tiny details, that 50-pixel brush magnifies along with the canvas, appearing visually massive on your screen and forcing you to lower the brush size slider manually.

When you enable Lock Brush to View (represented by the eye icon next to the brush size slider in the Tool Options dock):

  • Screen-Relative Sizing: The brush size is bound to your monitor's viewport rather than the image matrix. A brush set to 50 pixels will physically measure 50 pixels on your display screen at all times.
  • Dynamic Canvas Scaling: As you zoom into an image, the brush covers fewer image pixels on the canvas. As you zoom out, the brush covers more image pixels.

Why It Matters for High-Resolution Workflows

Working on high-resolution canvases (such as print-ready illustrations at 300 DPI or 4K/8K digital paintings) requires switching rapidly between broad composition strokes and microscopic detail work.

  1. Effortless Detailing Without Resizing: Instead of using keyboard shortcuts or sliders to scale your brush down for fine lines (like eyelashes, textures, or highlights), you simply zoom into the canvas. Because the brush maintains its visual diameter on your screen, zooming in automatically gives you a micro-scale stroke relative to the image data.
  2. Natural Drawing Experience: This mechanism mimics traditional drawing. When traditional artists need finer strokes, they naturally lean in closer to the paper. "Lock Brush to View" replicates this behavior by turning the zoom level into your primary brush-size controller.
  3. Consistent Stroke Weight on Display: Artists working with line art can keep their line thickness visually uniform from their perspective while navigating different sections and zoom levels of a project.

When to Disable the Feature

While beneficial for organic painting and detailing, "Lock Brush to View" should be disabled when exact pixel consistency is required across the canvas. If you need a border, texture stamp, or outline to measure a precise number of canvas pixels regardless of your current viewport zoom, leave the setting unchecked to keep the brush anchored to canvas resolution.