Convert CAL to PRC

Understanding CAL and PRC file formats

CAL files are raster image files, commonly used for fax documents and scanned images. The CALS Raster format, developed by the U.S. Department of Defense, is known for its monochrome bitmap images and is often used in engineering and technical documentation.

PRC files, on the other hand, are eBook files used primarily by Mobipocket Reader and some Amazon Kindle devices. The PRC format supports text, images, and advanced formatting, making it suitable for digital publications and eBooks.

Why convert CAL to PRC?

Converting a CAL image to a PRC eBook format is useful if you want to read scanned documents or technical drawings on eBook readers. This process involves converting the raster image into a format compatible with eBook devices, often requiring OCR (Optical Character Recognition) to extract text from the image.

How to convert CAL to PRC

Since CAL and PRC are fundamentally different formats (image vs. eBook), the conversion is a two-step process:

1. Convert CAL to a common image or PDF format (such as TIFF or PDF) using an image converter.
2. Convert the resulting file to PRC using eBook creation software, optionally applying OCR if you want selectable text.

Recommended software for CAL to PRC conversion

• XnConvert: Use this free tool to convert CAL files to TIFF or PDF. Open your CAL file and use File → Export to save as TIFF or PDF.
• ABBYY FineReader: For OCR, open the converted image or PDF and use File → Save As to export as a text document.
• Calibre: Import the text or PDF file and use Convert books to select PRC as the output format.

Step-by-step conversion process

1. Open your CAL file in XnConvert and export it as a TIFF or PDF.
2. If you need selectable text, open the exported file in ABBYY FineReader and perform OCR, saving the result as a text or PDF file.
3. Import the text or PDF file into Calibre.
4. In Calibre, select the file and click Convert books. Choose PRC as the output format and start the conversion.

Conclusion

While there is no direct CAL to PRC converter, using a combination of XnConvert, ABBYY FineReader, and Calibre provides a reliable workflow for converting scanned images or technical documents into eBook format for convenient reading on PRC-compatible devices.