Frequently Asked Questions
Find comprehensive answers to frequently asked technical questions regarding manga scanning resolution, DPI, file formats, and scanner hardware.
Continuous-tone color photographs lack periodic halftone screens, meaning 300 DPI is often sufficient to capture all visible detail. Manga, however, is printed using mechanical screentones—regular grids of tiny ink dots spaced at 60 to 85 lines per inch (LPI). Scanning at 300 DPI samples only 3.5 to 5 scanner pixels per printed dot. This violates the Nyquist sampling criterion, generating harmonic interference waves known as moiré. At 600 DPI, each dot is resolved by 7 to 10 pixels, completely preventing moiré waves.
Never force a bound paperback volume flat against the scanner glass using heavy books or excessive hand pressure. Instead, consider three preservation methods: 1) Use an edge-book scanner (such as the Plustek OpticBook series) where the platen glass extends to within 2mm of the edge, allowing the spine to hang naturally; 2) Use an overhead camera scanner with a 45-degree V-cradle; or 3) Use a CCD flatbed with a deep focal field (~5mm), which keeps gutter text legible even when gently curved.
For master archiving, use 8-bit grayscale Lossless PNG or TIFF with Deflate/LZW compression. Never save initial scanner outputs directly to lossy JPEG; JPEG compression introduces 8×8 DCT block artifacts and ringing noise around fine black ink lines. Save master copies in lossless format, perform deskewing and margin cleanup, and only export to WebP or high-quality JPEG for tablet distribution.
In nearly all cases, NO. Scanner driver descreening filters apply a heavy optical or digital Gaussian blur to smooth out halftone dots. While this eliminates moiré on low-resolution scans, it severely degrades fine linework, speech bubble text, and crosshatching. The superior approach is to scan at 600 DPI with descreening disabled, capturing pristine line art naturally.
CCD (Charge-Coupled Device) scanners utilize real optical lenses and mirror assemblies, providing roughly 3 to 5mm of focal depth. Portions of a manga page that curve into the book gutter remain sharply focused. CIS (Contact Image Sensor) scanners place a line of micro-sensors immediately behind the glass, with a focal depth of less than 0.5mm. Any paper not pressed flush against the glass blurs into a dark, unreadable smear.
No. The Manga Scan Quality Checker operates 100% locally within your web browser using HTML5 FileReader and client-side canvas APIs. No image data is transmitted over the network or stored on any server.