A Family History Mission: The Challenges of Digitization

No. 46

Note: You can do a Google search for "A Family History Mission James Tanner" to see all the previous posts in this ongoing series. You can also search for "James Tanner genealogy" and find them.

The document shown above is actually from Rhode Island and not one of the documents we are digitizing here in Annapolis at the Maryland State Archives. After spending a couple of months digitizing and preparing documents day after day, I find that my perception of what I am seeing online has changed considerably so I decided to show some of the digital images and discuss what you are actually looking at when you see the images on FamilySearch.org.

Let's look at the document above. First of all, it is a photograph of two pages in a book. The image also has an "attachment." That is the piece of paper covering up part of the text of the book. Properly, there would have to be another photo of the same page showing the part covered by the attachment. The book is laying on a camera stand and the camera is situated directly over the pages to be photographed. Here is a photo of one of our camera stands.

In this photo, you can see three clamps used to hold the book level. If you go back to the photo at the beginning, you can see a clamp that is just barely visible in the lower left-hand corner of the book page. The idea here is that the pages of the book have to be kept flat and perpendicular to the camera so that the images are in focus at a high resolution. Every time we start taking photos, we have to calibrate the camera. This means we test the focus, white balance, and resolution or lines per inch before taking any photos. We do this to assure that the images are clear and uniform. We have two large lights on either side of the camera stand that need to "warm up" every day for fifteen minutes so that the light is uniform.

Here is a photo of the lights with a "whiteboard."

By taking a photo using the whiteboard, the camera is calibrated to white with the available lighting. This allows the camera to "see" the book being photographed in the existing light and take the best possible photos. It is essentially a way to measure the intensity or temperature of the light. However, since all these photos are in grayscale, it is really a way to set the amount of light entering the camera lens, i.e. the aperture or f-stop.  But since this camera is a fixed installation, the aperture remains the same but the speed of the sensor chip can be modified. The easiest way to understand what is happening is to say that the camera adjusts to the light.

However, the grayscale, or relationship between light and dark areas also needs to calibrated. For this, we use a standard Kodak grayscale strip. The camera reads the strip and makes the adjustments to get the best contrast for the photos.

If we are taking pictures of single page documents, then the distance from the document to the camera never changes. But if we are taking pictures of a book, then every time we turn a page the distance from the lens to the page changes slightly and the level of the pages also changes. As we work through a book, we have to constantly be changing the level of the two sides of the book to keep the plane of the pages level and perpendicular to the camera. We get better at this with practice. We use a series of wedges and blocks to level the books. We also use foam cushions.

Well, that's enough for today.