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Film Copy Box

Do-It-Yourself Film Digitizer

Lieutenant Robert J. Garrett Supervisor,
ID/Technical Services Middlesex County Prosecutor's Office

Awhile ago, I was shopping around for a film scanner so I could archive my old cases. Unfortunately, most of my work was done on medium format film. Scanners for 35 mm film can be had for under $200. Adding the capability to scan medium format negatives can raise the price five fold. I decided to check out the used equipment market. I found that some early film scanners worked very differently from what we are used to. Instead of moving the negative across a static sensor or moving a sensor over the film, these scanners used a single CCD chip and exposed the film with a burst of light.

I considered this methodology and in half an hour had designed a multi format film digitizer that would cost under $25.00! There is a catch. The price does not include the static CCD. The image capture is provided by your digital camera. What I had put together was really a platform to mount negatives or slides, illuminate them for proper focusing and finally expose them to the camera with a flash of properly balanced white light.

This capture method is actually more efficient than the conventional scanning means. Scanning a film negative at high resolution can take some time. Using the Copy Box, you can record negatives or slides as fast as you can push the shutter button.

To construct a Copy Box of your own, you will need:

Materials

1-sheet of white 24" x 36" 3/8" foam core board
2-pieces of 5" X 6" clear glass
1-sheet of heavy black card stock (size will depend on how many different film carriers you need).

Tools

Xacto or razor knife Hot glue gun
Additional Equipment Small electronic flash unit PC cord extension
4-7 watt accessory lamp

Digital camera (3 MP or better) with macro or close up lens and external flash connection

Construction

Starting with the end pieces, cut a round 1 1/4" hole near the bottom and centered on one piece. This will receive the focusing lamp. On the other end piece, cut a rectangular hole, centered top to bottom and side to side. This will be for your flash unit. The actual size may vary depending on the flash used. Hot glue an end piece, wide side down, to each 14" end of the base.

Next, hot glue the side pieces to the end pieces and the base. Cut a 4 5/8" X 3 5/8" rectangular opening at one end of the top piece. This size will accommodate a 4 X 5 negative. Do not glue the top to the box. This will allow you to store accessories inside the box when not in use.

Use heavy black card stock for film carriers. Make each carrier the same size as the glass,

5" X 6". Cut openings in each film carrier. The size will depend on the film format being copied.

Use the following guide:

35 mm 1" X 13/8" (35mm X 24mm)
6 X 6 (120) 2114" X 2 114" (57mm X 57mm)
645 (120) 2 114" X 17/8" (57mm X 42 mm)
4"X5" 3518"X45/8"(118mmX92mm)

Figure 1 (top): This layout makes efficient use of your material.

Figure 2 (above): The assembled Copy Bo. The opening on the top piece sits over the accessory lamp for focusing. The flash is at the opposite end allowing for more diffused light.

Fig 3 (left): The film carrier exposes on frame at a time and may be used with glass above and/or below the negative.

The strobe is mounted in the hole at the opposite end of the box from the negative. A pc cord is connected between flash and camera. The accessory lamp is mounted in the hole under the negative to assist focusing.

Using the Copy Box

Mount your camera on a copy stand or tripod. The camera should have a resolution of 3 mega pixels or better. Slide the assembled Copy Box under the camera position. Insert the flash unit into the end slot and attach a pc cord between flash and camera. Place the negative carrier over the hole in the top of the box. Put the negative in place and mount the glass on top to hold the negative flat. Turn on the accessory lamp. Adjust the height of the camera so that the negative fills as much of the view finder as possible. The camera should be in macro mode. If your camera has an optical zoom feature, this may help. Do not use digital zoom as it will diminish the clarity of the image. Carefully and accurately focus the camera on the negative image. It is best to use the manual exposure mode if available. If your camera uses a focal plane shutter, make sure the shutter is set to its synch speed. Take the picture. Repeat for as many pictures as you need.

There are some things you should keep in mind. If the room you are in has overhead lighting, turn them off so they don't reflect in the film carrier glass. The fact that you are using a digital camera allows you to immediately check your exposure. Adjust exposure settings until you record what appears to be a negative of good overall density. You will need to use software to reverse the negative into a positive image that you can print out or use on your computer. This is easily done with Adobe Photoshop®. There are programs that will do the reversal and allow a certain amount of image adjustment that can be had for free. Irfanview, available at http://www.irfanview.com/ or The Gimp at http://www.gimp.org/ are two of the most popular ones.

If you are going to be recording many images, you should consider getting an AC power supply for your camera. Digital cameras eat a lot of batteries. Also, adjust the power saving settings on your camera so it doesn't shut down or hibernate after a few minutes of inactivity. This will eliminate having to reset the shot when the camera powers up again.

Another nice thing about this system is that it does not require a computer during the capture process. In fact, its portability is limited only by the charge in your batteries and the size of the camera's memory card. The Copy Box may be assembled "hinged", that is, put together with binding tape at all the base joints so it can be folded flat for easy storage and transport. The accessory/focusing lamp can be replaced by a small flash light.

For further information contact the author at : PO Box 2413, Edison, NJ 08818 or rjgarrett@idman.com.

RESULTS: the images from the film scanner appear slightly sharper than those from the Copy Box

(above) Image from negative copied on the Copy Box and close up detail of the same image. The image recorded on a 4 mega pixel camera.
(above) Images from the same negative, scanned on a Minolta Dimage multi scanner at 1128 ppi, the highest setting for the format (120 film 645 format).

The fingerprint on the left was captured using the Copy Box and 4 mega pixel camera. The image on the right was made from the same negative and captured on a Minolta Dimage multi scanner at 1128 ppi. Both images are cropped from their originals.



Copyright 2011 - Richard Warrington
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