Translayer is powered by Google Gemini’s multimodal AI — one of the most capable visual understanding models available. But AI quality scales with input quality. A blurry scan, a heavily compressed JPEG, or a page with severe geometric distortion will produce worse output than a clean, high-resolution source image.
In this guide, we detail the best practices for preparing your book pages for AI translation, focusing on selecting the right file formats, optimizing resolution, and ensuring clean scans for the best possible results.
This guide is the single most important thing to read before your first translation project.
File Formats
PNG (Recommended)
PNG is a lossless format — it preserves every pixel exactly as captured, with no compression artifacts. For book translation, this matters most around text edges, where JPEG compression creates blurring and ringing artifacts that confuse OCR and text detection.
Use PNG when:
- Translating anything with small text (footnotes, captions, fine print)
- Working with line art, diagrams, or illustrations with sharp edges
- File size is not a constraint
JPEG
JPEG uses lossy compression. At high quality settings (90–95%), the visible difference from PNG is minimal. At lower settings, compression blocks appear around text, reducing detection accuracy.
Use JPEG when:
- File size is a constraint (uploading many large pages)
- Set quality to 90% or higher in your export settings
- Content has no very small text or fine-line details
Never use JPEG for:
- Manga (fine hatching lines and small bubble text)
- Books with 8-point or smaller footnotes
- Any page where text is on a complex patterned background
WebP
WebP is a modern format with excellent compression. Translayer accepts WebP, but for book content originating from print or high-quality digital files, PNG or high-quality JPEG will generally give better results. WebP shines for web-native content (screenshots, web pages), not print-origin material.
Resolution Guide
Resolution (DPI — dots per inch) is the single most important factor in translation quality for print-origin content.
| Resolution | Use Case | Quality |
|---|---|---|
| 72–96 DPI | Screen captures, web screenshots | Poor for print content |
| 150 DPI | Low-quality draft | Acceptable for large-text content only |
| 300 DPI | Standard print quality | Good for most books |
| 400 DPI | Recommended for illustrated books | Very good |
| 600 DPI | Technical content, fine print, manga | Excellent |
When to use higher resolution:
- Small text (8pt or smaller footnotes, captions)
- Dense technical diagrams with labeled components
- Manga and comics (fine line art, small speech bubble text)
- Books with watermarks or colored text on dark backgrounds
Maximum practical limit: There is a point of diminishing returns around 600 DPI for most content. Files above 600 DPI are significantly larger without meaningful quality improvement. For standard books, 300–400 DPI is the sweet spot.
Scanning Physical Books
If you are digitizing print books, scan quality determines everything downstream.
Scanner Settings
- Resolution: 400 DPI minimum, 600 DPI for detail-heavy content
- Color mode: RGB for color books, Grayscale for black-and-white
- Format: PNG (no JPEG compression during scan)
- No auto-adjust: Disable automatic brightness/contrast correction — it can destroy fine text at edges
Handling Page Curl
The biggest quality killer in book scanning is page curl near the spine. Strategies:
- Book cradle scanner (e.g., CZUR, Fujitsu ScanSnap SV600) — designed for bound books, captures flat even at the spine
- Flatbed scanner with firm pressure — press the book flat; accept some slight shadowing near the spine
- Camera + book scanning app (e.g., Microsoft Lens, Adobe Scan) — for quick jobs; quality is lower but usable for large-text books
For important projects, a flatbed scanner produces better results than a camera phone, even a recent high-end phone.
Post-Scan Cleanup
Minimal cleanup improves results significantly:
- Straighten pages — ensure horizontal text lines are level (most image editors do this automatically)
- Remove dust spots — a single large dust spot on a page of small text can confuse detection
- Deskew — if pages are slightly rotated, straighten them. Translayer handles mild skew well, but 5°+ rotation reduces accuracy
- Crop to page edge — remove scanner bed borders and any parts of the book cover or facing pages that bleed into the scan
Exporting from Digital Tools
InDesign (Most Common for Professional Books)
- File → Export → PNG
- Resolution: 300 DPI minimum
- Color Space: RGB
- Anti-alias: On
- Export as: Pages (not spreads, unless your book uses full-bleed spreads)
- Do NOT export with text on a separate layer — export the flattened composite
Affinity Publisher
- File → Export → PNG
- Resolution: 300 DPI
- ICC Profile: embed sRGB
- Export as flattened (not layered PNG)
Canva
Canva’s free export is only 96 DPI. To get print-quality resolution:
- Download → PDF Print (this exports at 300 DPI)
- Use Adobe Acrobat, Smallpdf, or ILovePDF to convert each PDF page to PNG at 300 DPI
Microsoft Word
Word is primarily a word processor, not a layout tool, but some illustrated books are created in Word.
- Save as PDF first (File → Save As → PDF)
- Convert PDF to PNG at 300 DPI using any PDF converter
Pre-Upload Checklist
- Format: PNG or JPEG at 90%+ quality
- Resolution: 300 DPI minimum (400+ for detailed content)
- Orientation: All pages correctly rotated, reading direction up
- Dimensions: Consistent across all pages in the project
- File naming: Sequential numbering (page-001.png, page-002.png)
- Test page: Ran a single page through Translayer and reviewed output
- No bleed marks, printer marks, or guide lines visible
Summary
In summary, the quality of your AI translation output is directly linked to the quality of your input files. By using lossless formats like PNG, setting a resolution of at least 300 DPI, and ensuring clean, correctly oriented scans, you can maximize the accuracy and visual fidelity of your translated book pages.
Frequently Asked Questions
What is the best file format for uploading book pages to Translayer?
PNG is highly recommended because it is lossless and preserves sharp text edges. Use high-quality JPEG (90%+) only if file size is a major constraint. Avoid WebP for content originally intended for print.
What is the minimum resolution required for good translation quality?
300 DPI is the absolute minimum for acceptable quality. For books with small text, fine illustrations, or manga, we recommend 400–600 DPI to ensure the AI can detect every detail accurately.
How should I handle page curl when scanning physical books?
Use a book cradle scanner if possible. If using a flatbed, apply firm pressure to keep the page flat against the glass. For camera scans, use a dedicated document scanning app and ensure even, bright lighting.
Can I mix different page dimensions in one project?
It's best to keep all pages in a project at consistent dimensions and resolution. Mixed sizes can lead to inconsistent font rendering and layout quality across the translated pages.