December 6, 2006

Bitonal TIFFs

Bitonal images force computer scanners to treat that dot or point per inch, as set by the resolution, as either a black or white dot. Bitonal images are ideal for text for several reasons.

1. "Blackened" text, particularly at a high resolution, is easier for an OCR engine to recognize. Text in a grayscale format (see next entry) has a "blur" effect around the edges of the text, making it more difficult for OCR engines to recognize a letter correctly.

2. Bitonal whitens the background, creating an even "page tone" for all of the documents, whereas grayscale or color imaging would pick up all of the variants in page coloration and even lighting!

3. Bitonal images are much smaller than grayscale and color images. This makes the images themselves much more manageable for purposes of scanning, data transfer, Webt or FTP uploading and downloading, and Web displaying.

Here is a page spread from a religious publication called Restoration. On display is a bitonal, 300 dpi TIFF file.

No comments: