Image Conversion Considerations

As companies merge, grow or move to new document storage systems, they need to decide how to treat their document and image repositories. For companies with very large repositories, document and image conversion can be time consuming, expensive, and risky if the conversion is not done correctly.

Conversion is often done to solve issues ranging from viewing legacy content or unsupported document formats to archiving files. However conversion may or may not be the answer. The files can be left in their original format and can continue to be accessed through the legacy application or a new solution can be implemented that supports both old and new document and image formats.  If conversion is the answer then TIFF and PDF are generally selected as the final output.  It is important to understand the pros and cons of each format to determine which will meet your specific objectives. 

TIFF File Format

TIFF, or Tagged Image File Format, is a flexible public domain raster file format container commonly used to store and/or send raster graphics between programs and computer platforms. TIFF is widely supported by various applications including image manipulation applications, publishing and page layout applications, scanning, faxing applications and others.  It was established as a standard method of storing black-and-white scanned documents in 1986. Many companies use TIFF because the format presents many advantages:

  • TIFF is very flexible about information fields and compression schemes.
  • TIFF files are platform independent so they can be used on Macs and PCs.
  • TIFF defines support for multiple images in a single file. This enables multiple pages and multi-page documents to be saved as a single TIFF file.
  • Most TIFF file formats are lossless and retain image quality even when the image is altered.
  • Almost every image-editing program can create or save a file in TIFF format at any resolution.
  • TIFF files support various kinds of compression which is beneficial for conserving server space when archiving.

Today, TIFF files are also widely used with high color depth images, making it a popular format for graphic design firms and desktop publishers. However, it is important to know that color images, which are referred to as 24-bit, are not as easy to work with as the 1-bit black and white. Commonly people convert 24-bit TIFF, or color images, to JPEG, which supports 24 bits of color information better and there are more viewing applications that support JPEG. For this reason it is common to use JPEG for photos and similar continuous tone bitmap images. However TIFF to JPEG conversion presents some challenges:

  • Some viewers may not support color images.
  • JPEG lossy compression methods produce a smaller compressed image which loses some image quality.
  • Various viewers may implement TIFF support differently so be aware of which one you use. The Kodak/Wang viewer, for example, can read in 24-bit TIFF-JPEG, but cannot read TIFF-JPEG images that are in 8-bit grayscale, meaning images that contain gradations of gray.

Learn more about the TIFF File Format

PDF Format

PDF, or Portable Document Format, was developed by Adobe Systems to represent two-dimensional documents in a device/resolution independent fixed-layout format. This means that the original format, font and style remain intact regardless of where they are viewed. PDF files can contain either raster objects or searchable objects (vector).  

Raster PDF files are bitmap images of the actual document.  Because the content in the document becomes part of the image the content is not searchable.  Raster PDFs can pose challenges if you require a high degree of fidelity when zooming in on the image.

Searchable PDFs (Vector) maintain the integrity of the content for display by drawing the various objects within the document rather than rendering it as an image.   Because the content is not an image it is searchable and also remains clear and intact when zoomed in to any level.

Both versions of PDF are beneficial depending upon your use case.   Because PDF is universally accepted as a standard format, it makes it possible to easily share information with a lot of people.  In addition to being universally accepted, PDF offers a number of advantages:

  • PDF documents are highly portable across platforms.
  • PDF documents maintain original formatting (WYSIWYG) for display and printing.
  • Almost any file can be converted to PDF. For example, when IBM discontinued support for its ImagePlus solution, some companies chose to convert their AFP documents to PDF to ensure accessibility.
  • Most computers have programs installed to read PDF files and the download for anyone who needs it is at no cost.
  • It is possible to save any searchable document format including MS Word, MS Excel, AFP and PCL files as searchable PDFs.

While there are many benefits of PDF there are also some challenges to consider:

  • If you are using a viewing technology that requires a download on the client side, such as Acrobat Reader if the user doesn’t already have it, you are going to have to accommodate for the delay that is inherent in order to open up PDF.   
  • TIFF files, or other bitmap images saved as PDF, are not searchable unless processed with an OCR program.
  • While PDF offers several very good compression options to reduce file size and speed up download time, the fact still remains that even with compression multi-page PDFs are slow to download. To eliminate the slow download issue you can leverage a solution that utilizes the power of the server to break up the multi-page documents into single pages that can be sent to the client on demand rather than within the entire document. 

Learn more about the PDF File Format

PDF to TIFF Conversion

A PDF to TIFF conversion can be beneficial if you need a simpler image format for archiving:

  • The TIFF structure is more simplistic than PDF and therefore developing applications to handle such images are easier to implement.
  • Documents converted to TIFF will be in a bitmapped format. This format protects the document or image from accidental additions or changes. 

But PDF to TIFF conversion has its own challenges that you should be aware of before committing your repository or archive to this format. Many conversion applications require a print driver which slows down the conversion process.   You may want to consider a PDF to TIFF application that does not invoke the print driver, especially if you need to convert large number of files in a batch process.

PDF to JPEG Conversion

The PDF format is well suited for the storage and exchange of electronic documents, but there are cases when JPEG is the better choice.  Here are some benefits of converting PDF to JPEG:

  • JPEG format is more suitable for PowerPoint presentations because the compression code creates a smaller file.
  • JPEG is supported by web browsers and can be viewed without installing an additional application (i.e. Adobe Acrobat). 
  • JPEG format protects Web-published document from being altered.

Keep in mind that with the PDF to JPEG conversion using the inappropriate methods may slow the process or the image quality can be compromised.

  • If you are using a conversion application that invokes a print driver, conversion will be slow for large numbers of documents.
  • JPEG employ’s lossy compression, which is a method of image compression that produces a smaller compressed image, but in the process, loses some of the image quality.  However that decrease is not often visible to the human eye.
  • Text rendering in JPEG is not as clear as PDF.
  • More information on PDF to JPEG conversion

When managing multiple document formats, your specific conversion challenges require you to assess exactly which conversion practices best suit your needs. TIFF, PDF and JPEG present widely used conversion solutions, but there are also many more to explore.

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If you have document and image conversion questions or would like to discuss your requirements, please contact us 617-607-2010.

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