Non-Photo Blue Comic Art Boards

Non-photo blue was designed for traditional darkroom and copy-camera workflows, where orthochromatic film was blind to blue wavelengths. Modern flatbed and CCD scanners use full-spectrum RGB sensors and will capture the blue guides at standard settings — they are not automatically invisible.

Why the blue may appear in your scan: Most desktop scanners capture all visible wavelengths at once. At default brightness and contrast settings, the guides can register as a faint blue channel in the raw scan file.

Removing the blue in post-processing - common approaches:

• Grayscale conversion - Convert the scan to grayscale. The blue guides typically drop to a very light gray value that can be clipped out by raising the Levels or Curves black point.
• Channel selection (Photoshop / GIMP) — Open the Red channel only. The non-photo blue ink records at its darkest in the Red channel, but your pencil and ink lines record darker still — use Levels to isolate linework and discard the guide tone.
• Brightness/threshold adjustment - Scan in grayscale mode at 600 dpi, then raise brightness or apply a threshold to push the light guide value to white while keeping ink lines black.
• Scanner software presets - Some scanner drivers include a "line art" or "text" mode that applies an automatic threshold; this can eliminate the guides entirely depending on density.

Test before production: Scanner sensitivity and software defaults vary. Run a test scan on a single board before committing to a full project. Adjust your threshold or channel workflow until guides disappear to your satisfaction, then lock in those settings for the run.

Non-photo blue guides are a precision layout tool. A brief post-processing step is standard practice in professional comic production workflows.