Using the Scan-n-Share

A Scan-n-Share is a camera stand that allows you to easily take pictures of papers and objects. It was designed by a team at FamilySearch to help you take the best quality pictures possible with the technology you already have, your cell phone.

Overview
Cell phones and other modern cameras have all but eliminated the need to do any more than press a button to take a quality image. When these cameras are used for purposes other than regular pictures of your family and friends or your vacation pictures, the resulting images are often less than your expectations.

When a camera is used to capture an important document, you need to understand what is required of you to help the camera take the best picture.

Below, you will find a few items, which if properly understood and implemented, will improve your camera’s ability to take the excellent images.

File Format and Compression
Cell phones usually save images in either JPEG or the newer HEIF/HEIC file format. Some apps can be used that save the images in TIFF or DNG formats. What does this all mean?

File formats like JPEG and HEIF/HEIC, use algorithms to compress and make the image file smaller so that more images can be stored. However, there is a trade-off in getting smaller files. When the JPEG or HEIF/HEIC file is saved, the algorithm looks for photographic information that may not be easily detected by the eye and it disposes of this information to make the file smaller. This lost information can never be recovered. In most cases, the lost information is never noticed. However, in images of documents, this can be a problem. For example, ghosting around letters may begin to appear, faint lines may blend into the background or the subtle shading of loops and crossovers of lines may be lost in an effort to make the file size smaller.

TIFF and DNG file sizes tend to be much larger than those of the JPEG and HEIC formats. The TIFF format is very robust, but often is very large in size and may not be the best choice for a cell phone. The DNG tends to be a smaller size image than the TIFF, and it can contain all the pixel detail often lost in the JPEG or HEIF/HEIC formats.

The DNG format on a cell phone would, in most cases, be the best format for high image quality. File size would increase significantly over JPEGs and thus less images could be stored on the cell phone before they would need to be downloaded.

Generally, if you set your cell phone camera to capture the best quality and largest JPEG image, you will get a good compromise of quality and size. The current iPhone cameras give the choice between HEIC and JPEG image formats in the camera apps settings, under Formats, as High Efficiency (HEIC) or Most Compatible (JPEG).

Even Illumination
When using the Scan-n-Share camera stand, you need to take care to place the stand where it does not have direct sunlight or flood light shining on the stand area. This ‘extra’ light can cause an uneven illumination across the documents. Uneven illumination can make it more difficult to correctly expose all regions of the document correctly and information can be lost in one area as correct exposure in another area is obtained.

White Balance
The Scan-n-Share lights are set with a color balance that is neutral and closely matches natural sunlight. This color balance allows the white areas of the document to be captured more closely to what they actually look like, If the color balance is off, these white areas may have a slight color cast, like a slightly blue, red or other color tint.

Some cell phone apps may allow you to set the white balance to a close match to the original. This is often done by capturing a white piece of paper and making the adjustments to the color balance so that the white paper appears white on the image.

Correct Exposure and Tonal Range
Cell phones often select what they believe to be the correct exposure or lightness or darkness for an image. This is based on a theory that says that if you take and mix all the colors together in a typical image, the result would be a gray color. Using this theory, the camera adjusts the exposure to achieve this gray color average. This works well for most photographs, but if the image is overly bright or dark, this creates an image that does not match or capture the information of the original image.

Many cell phone apps will allow you to change the exposure to match more closely the original. Ideally, you can use a target, like the Tiffen Q13 grayscale target, to set the exposure of the camera so that it can capture and see the different grayscale levels from whitest white to darkest black. When properly adjusted, the camera will now be able to capture all the subtle tonal changes found in the original document.

Capturing Fine Detail – Pixels-per-Inch
To capture all of the fine detail of a document, you should use a cell phone with a good quality camera. Most modern cell phones have at least a 5-megapixel camera. This means that the camera captures 5 million points in an image. Each point is a pixel. The closer the camera to the document the more pixels that are being used to capture the document. More ideally, a 10-megapixel or larger camera should be used to capture the images.

The measurement of this fine detail is called spatial resolution or sometimes just resolution. It is typically measure by counting the number of pixels captured horizontally or vertically in one inch. This measurement is called PPI or Pixels-per-Inch. Sometimes you may hear people refer to this ad DPI or Dots-per-Inch. PPI is the correct term.

Often, ordinary photography will capture an image without enough resolution. If you zoom in the image becomes blocky and lacks detail. This means that the camera needed more pixels and/or the camera needed to be closer to the subject.

A 5-megapixel cell phone camera will barely have sufficient resolution to capture an 8.5” x 11” with good detail. The older the documents the more critical this becomes. Using a 10-megapixel or higher resolution camera will allow for better images that can be used to show better detail from the original document.

Focus and Motion Blur
Focus is critical for good image capture. Many cell phone camera apps allow the user to set and fix the focus for a series of images. Where possible the focus should set and fixed for all documents that are the same distance from the camera.

Another factor that can also make an image look out of focus in what is called motion blur. This when either the camera or the document moves during exposure. The Scan-n-Share camera stand can eliminate most blur if you are careful not to hit the stand or camera while an image is being taken. There are devices and apps that allow for remote triggering of the camera without touching it. Where possible use something other than touching the camera to trigger it to take an image. For example, a remote Bluetooth trigger can be used to trigger each new exposure. Some cell phone apps trigger a new exposure after they see that the motion in front of the camera lens has stopped. So you could reach into the change a page and after the change, when the camera does not detect more movement, it takes the next image and waits.

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