The questions can range from technical to legal to philosophical, but the most common question in nearly every one of these discussions remains:
Should newspapers be scanned in bitonal or grayscale?
• Bi-tonal – Scanning process that uses black or white (bi-tonal) as the two-tone values for each pixel.
• Grayscale – Scanning process that uses 256 (Gray) tones as the value for each pixel.
Then, before we answer the question of “bitonal or grayscale? “, we must first ask another question:
What is the goal of this project, and what is the best approach for these images to meet that goal?
If the goal of the project is to provide a photorealistic representation of the page, grayscale is a more accurate fit for the project. If the size of each file image does not matter and the client has time/server space to index each file, grayscale may be the best bet. If the project requires images to meet library of congress standards for imaging grayscale may be the best fit. However this quality comes at a cost both in terms of production, and in maintaining the collection.
Depending on how many images are to be included in the archive,, simply due to the file size of grayscale images may not possible without investing significant capital into hardware and software.
If the goal of the digitization project is to develop a fully key word searchable database with a high return rate on keywords, a browse-able index, and , reduced load times for the end user, and at a per image cost that allows for a greater volume of images can be made accessabel…. then bitonal may be the best fit.
Bitonal images require almost half the server storage space of grayscale images and provides a more satisfying user experience, as both search and image load times are significantly shorter than the same newspaper page represented in a grayscale format. Most importantly, Scanning a newspaper page bitonially, creates a very clean, very high quality “text first” approach to image capture due to the elimination of “background noise” found in the inexpensive paper stock of newspapers.
At the Advantage Companies, we view digitization as an important part of the preservation process, supplementing microfilm as a more practical method for providing access, outreach and education.
Our position is that a digital copy of a newspaper does not replace the microfilm in terms of preservation, but it is a valuable resource to compliment the microfilm with advantages in ease of use and ability to search terms.
Typically we find our partners are interested in striking a balance between quantity, quality and budget. More specifically, the best balance of quality and quantity that can stretch the budget available for a project. If any one of these three factors is given more priority than the other two, decisions must be made as where to make concessions.
The photorealistic quality of a greyscale newspaper page, comes at a premium cost, therefore the number of images (volume) will be limited by available budget.
Many of the libraries and historical societies we work with already rely on grants for important scanning projects. Price is a factor and that is why we take this into consideration along with the quality of the product.
The Advantage Companies solution is budget friendly to our partners and allows for entire collections to be done effectively and affordably.
For our digital archives, we recommend and encourage our partners to use bi-tonal scanning which produces quality results for printed text on newspapers at a price that isn’t cost prohibitive.. Bi-tonal scanning also keeps the file sizes smaller and the search times shorter than other methods. We find Bi-tonal to be our most commonly used method of scanning, but each project is different and can require a variation of different scanning methods to produce the best results.
Content is key and we consider the most important aspect of scanning to be capturing the words on the page. That’s why we don’t have a “one size fits all” solution. Grayscale has a place in our arsenal, and we find it invaluable in some situations in which bitonal scanning simply is not the best choice, For instance, Greyscale can produce much better results in handwritten or older, damaged documents. With the 256 tones available, Grayscale isable to display finer details than bi-tonal.
We also receive questions from our clients who are interested in following the technical guidelines set forth by the Library of Congress for their National Digital Newspaper Program.
NDNP technical specifications require a 400 dpi 8-bit grayscale archival image, production image, printable image and structural metadata to the standards of the Library of Congress.
We find that the costs associated with NDNP type projects to be prohibitive, and counterproductive when considered by smaller institutions. It greatly limits the amount of content a library can make available to its community. To put it into perspective, for every newspaper page digitized to NDNP standards, a local library could make nearly 13 pages available to the community using a more sot effective solution like bitonal.
In other words, the to digitize a single 100’ roll of microfilm (lets use 900 images as an example) to NDNP standards, would cost more than 10,000 images using the methods employed by Advantage and our over 500 library partners.
We work to keep the digitization project metrics for our clients in balance at all times: Keeping costs as low as possible and quality as high as possible that allow for as much volume as possible to maximize the budget allocated to the project.
Our methods, business model, and driving mission all converge on the singular theme: Ensure the content is preserved for the future and accessible today.
most popular service amongst our friends in the library community.
So….Greyscale or Bitonal? The answer is yes to both. Both have their place, and each specific preservation project should be evaluated on the needs, wants, and requirements of the library partner, Our default process for providing the highest volume possible is not always the appropriate solution, and we must always be consulting with our clients on “what is the right tool for the job”. When evaluating whether to scan in grayscale or black & white, consider the following:
Bitonal (Left) Grayscale (Right)
Why Scan in Grayscale:
• Grayscale scanning captures the natural state, coloring, texting & shading of historical content.
• Provides a more detailed photography profile of photographic images.
• Adheres to the Library of Congress National Digital Newspaper Project standard of imaging.
Why Scan in Bitonal:
• Bitonal scanning attempts to create a background that makes the text of newspapers stand out more clearly from the background of the page. (Eliminates “background noise” often seen in grayscale).
• If attempting to make content key word searchable, the lack of “background noise”, tends to give a higher rate of return on key word searching.
• Requires smaller file sizes of documents, which requires less storage space to store, upload, and search content.
• Database speeds perform at more optimal rate (comparatively) on a day to day basis.