Author Topic: Digital photography of Microfilm  (Read 1244 times)

Offline bugbear

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Digital photography of Microfilm
« on: Friday 23 June 17 13:40 BST (UK) »
I wanted to gather some wills (from around 1730-1800) for various people in my tree from Norwich Record Office. My hope was that I could end my visit with a full set of digital images of the wills. I knew from the online catalogue that they had them on microfilm. I also know that the NRO have a very liberal attitude to camera support/tripods. It can be summed up as "as long as it doesn't cause problems, you're OK".

Armed with this...

I knew that microfilm readers tend to have very uneven lighting, so that was an issue to consider. I was a little worried about screen reflection, although it turns out the reading area was dimly lit, so not a problem.

I set up my tripod around 4 feet away from the screen, which left me room to get between the camera and the reader to load/manipulate the film. I used a bit of zoom on the camera to get a full screen shot at this distance.

In order to compensate for the uneven screen lighting, and to avoid the possibility of any part of the image being unreadable due to bad exposure, I took 3 shots for each frame, offset by 2Ev. My camera is capable of auto-bracketing, and I used a timer release to avoid any camera shake.

I captured 12 wills, 32 pages, 96 images in this way, with a few "oops" moments, duplicates etc along the way. The staff at NRO were very helpful with some issues of film-reader manipulation, and locating wills on rather long microfilm reels.

When I came to process and finalise the images, I used enfuse to make a "best case" version of the 3 bracketed shots for each page.

Code: [Select]
enfuse --output="merge.tif" --exposure-weight=.8 --saturation-weight=0 --contrast-weight=0.2 shot_normal.jpg shot_plus2.jpg shot_minus2.jpg

This gives an image with is fairly uniform, but slightly lacking in contrast, so I used an automatic process (command line, but Gimp or Photoshop can do this as well) to stretch the contrast to be full from black to white.

Having said all that ... my biggest problems did not arise from digital photography or processing. The original micrfofilms were rather heavily scratched and of low contrast. Since the best I could possibly do it make a perfect copy of the microfilm, this set a low bound on quality.

The other problem was that the reader I was using would quite often not focus the whole image in one go. If one part of the image was in focus, another would be out of focus. Reading the film "there and then" this wouldn't be an issue. You'd just have one hand on the focus, and adjust.

Sadly, I didn't really appreciate the extent of this problem until I was processing and trying to decipher the images, back home.

To pre-empt the obvious question, I didn't try to read the wills at the NRO because I know that deciphering old wills is slow work (and I have use my annual leave days from work to be at the NRO). Worse, I make extensive use of online resources (e.g. old legal "boilerplate", placenames) to guide my interpretation; I also try whenever possible to include all references for my tree in digital form on my database.

I am happy to report that despite my images being imperfect, I have been able to successfully transcribe the particular information I needed from each will, and am in a position to make a full transcription if needed.

I hope this report of my technique, successes, and failures may be of help to anyone else attempting a similar task.

    BugBear
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Offline bugbear

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Re: Digital photography of Microfilm
« Reply #1 on: Friday 23 June 17 13:57 BST (UK) »
Attached - three raw shots of the 1764 will of James Reeve of Kenninghall

   BugBear
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Re: Digital photography of Microfilm
« Reply #2 on: Friday 23 June 17 13:59 BST (UK) »
Attached - merged image, and merged image with contrast stretch. The lighting is much more even.

  BugBear
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Re: Digital photography of Microfilm
« Reply #3 on: Friday 23 June 17 14:02 BST (UK) »
For final viewing, I have applied a Gimp unsharp-mask filter to the contrast stretched image. These crop-ins are from the bottom right (in focus) and top left (not well focused) parts of the image.

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Offline Guy Etchells

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Re: Digital photography of Microfilm
« Reply #4 on: Friday 23 June 17 14:04 BST (UK) »
First mistake could be due to having the camera so far from the screen, if you use a digital camera in those circumstances the camera tends to focus on certain parts of the image rather than the complete image. The closer you get the better the focus in most cases.

The sratches would in many cases have responded to hand processing rather than automatic processing.

Needless to say it would have been better to have the images scanned rather than photographed but that option was not available to you as I don't think the NRO have reader that scan the images as some libraries do
Cheers
Guy
http://anguline.co.uk/Framland/index.htm   The site that gives you facts not promises!
http://burial-inscriptions.co.uk Tombstones & Monumental Inscriptions.

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Offline bugbear

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Re: Digital photography of Microfilm
« Reply #5 on: Friday 23 June 17 14:12 BST (UK) »
First mistake could be due to having the camera so far from the screen, if you use a digital camera in those circumstances the camera tends to focus on certain parts of the image rather than the complete image. The closer you get the better the focus in most cases.
Since the only thing in the camera's frame was the flat screen of the reader, and the camera was positioned (roughly) central and perpendicular to the screen, it wouldn't really matter what part of the screen it chose to focus on.
So I don't think I had camera focus issues. Since I was able to use a tripod, I didn't care about exposure time, so I was using f8 just in case!
Quote
The scratches would in many cases have responded to hand processing rather than automatic processing.
I don't understand what you mean by this. Could you describe the hand processing you have in mind?
Quote
Needless to say it would have been better to have the images scanned rather than photographed but that option was not available to you as I don't think the NRO have reader that scan the images as some libraries do
Cheers
Guy

Hell, yeah. If they offered the use of something like this:

https://www.wwl.co.uk/micrographic-scanning-systems/uscan-universal-microfilm-scanner/

I would have bitten their arm off.

But they don't.  :'(

 BugBear
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Re: Digital photography of Microfilm
« Reply #6 on: Friday 23 June 17 14:16 BST (UK) »
Add; my longest (bright) exposure was 0.8 seconds. Tripods are very handy.

 BugBear
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Offline Guy Etchells

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Re: Digital photography of Microfilm
« Reply #7 on: Friday 23 June 17 14:37 BST (UK) »
Many libraries have since the 1980s offered a microfilm/fiche reader that can scan the image and either print the image or store it to hard drive the look similar to ordinary film/fiche readers with a connection to a laser printer such as the one shown here.
http://www.microfilmworld.com/pre-ownedminoltams-6000wscsipcinterface.aspx

They are not as good as the microfilm scanner to mention which scans the microfilm direct but they do offer a reasonable result.

The hand process in was manually removing individual scratches using something like Photoshop rather than bulk removal using the software which can remove parts of the text as well.

When we process images we use a mixture of the two types of processing due to time/cost restraints
http://anguline.co.uk/Framland/index.htm   The site that gives you facts not promises!
http://burial-inscriptions.co.uk Tombstones & Monumental Inscriptions.

As we have gained from the past, we owe the future a debt, which we pay by sharing today.

Offline bugbear

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Re: Digital photography of Microfilm
« Reply #8 on: Friday 23 June 17 15:05 BST (UK) »
The hand process in was manually removing individual scratches using something like Photoshop rather than bulk removal using the software which can remove parts of the text as well.

Ah, I see.
 
There's nothing in my sequence that removes scratches, either by hand or automatically; I just leave 'em in!

My goal is readability, not beauty. They're certainly not good enough to even consider printing as facsimiles of the original document.

 BugBear
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