Intro: Use Your Camera to Digitize Large-format Negatives.
Over the past few years, I've scanned all my 35mm negatives and now have digital copies of all of them (over 14,000 - phew!). But, I still have hundreds of really old large-format negatives taken by my family over the decades that I am unable to scan because they are too large to fit in my scanner. I've got prints that had been made of a few of the negatives, but print scan quality at 300 DPI is marginal and the dynamic range of a print is decidedly limited. And even worse, for those negatives that have not been printed, it is impossible to make out who or what they are of.
I wanted a quick and easy way to turn the negatives into positives and decided that my new digital camera could create those digital copies for me - all I needed to do was try it out to see what it could do.
Proof Of Concept
I placed a negative in a sunlight window and took a photograph of it (the negative below is my dad - taken when he lived on the Rosebud Indian Reservation in 1919.) I could see that the detail was good, but there was a lot of glare and the negative obviously needed to be held flat to the image plane. I needed a fixture that would hold negatives flat and which eliminated extraneous light and reflections.
The fixture needed to address the following requirements:
It must hold the negatives in a flat plane.
It must diffuse the light source so there is no hot spot.
It must hold the negatives within the focus plane of the camera.
It must be solidly mounted to my digital camera camera.
It must have a light shield to minimize glare from extraneous light.
It must to be quick and easy to load and unload.
Clear plastic - The camera side of the negative holder "sandwich".
Translucent plastic - The light source side of the negative holder "sandwich". This diffuses the light to eliminate hot spots.
Angle bracket - To hold the negative holder.
Metal bar - To mount the negative holder to the camera.
Cardboard - To make the light shield.
Screws, clips, duct tape and hinges - To hold everything together.
Except for the plastic, I had most of the materials on hand in various bins I keep for just these purposes. I bought the both sheets of plastic out of the scrap bin at Tap Plastics - so my total out-of-pocket investment came to about $2.00. (The plastic typically comes with a protective paper cover on both sides. Leave it on for as long as is humanly possible - I didn't and it's now got some very nice scratches on the surface.)
Step 1: Making the Negative Holder
Use the largest negative you have to determine where to cut out the aluminum angle bracket.
Cut the bracket to length (7").
Cut out the inner portion to leave room for the negative so the camera can see it when the plastic negative holder is ultimately mounted on the bracket.
Step 2: Fitting the Plastic to the Bracket
Cut the clear plastic sheet (7-1/2 x 4) so that it extends out beyond the bracket. This extension is where you will mount the light shield.�
Cut the translucent diffuser sheet to a smaller size (6-1/2 x 4) - you want it to completely cover the negative so it diffuses all the incoming light that the camera can see. This sheet is also smaller than the clear sheet so you can open and close it to put in your negatives.
Place the clear plastic sheet on the bracket and clamp it in place to drill the mounting holes. (In this shot, the clear plastic is still covered by its protective covering.)
Drill a small hole through both the bracket and the clear plastic.
Then, tap the clear plastic to accept a mounting screw. Make sure your screws are short so they don't protrude through the plastic and interfere with the diffuser sheet.
Next, use a larger drill to make the hole in the bracket larger so the mounting screw can pass through and mount the clear plastic on the bracket.
Step 3: Mounting the Diffuser Sheet
I hinged the diffuser sheet to the clear plastic to make negative changes quick and easy. I used small hinges that were intended to be melted into plastic. Using the 800 degree tip on my soldering iron, I melted them into place. The hinges worked perfectly, but I had to be very careful to not get the plastic too hot and distort it. The two plastics had different melting temperatures so I had to take care to not overheat one while trying to melt the hinge into the other.
In this shot, you can also see the tapped hole that holds the clear plastic on the bracket.�
Step 4: Tapping the Camera Mount
I used a 3/4" x 1/8" x 14" piece of metal to hold the fixture to the camera's tripod mount.�
I scavenged the mounting screw from an old potato-masher style flashgun mount and used that to attach the fixture to the camera. The mounting screw was captive to the flashgun once screwed through a hole in the flashgun mount, so I replicated this by drilling a hole at the far end of my mount using a No. 7 drill and then tapping it with an 1/4-20 NC tap.
Place a piece of rubber gasket material between the mount and the camera to hold the mount firmly to the camera.
Step 5: Setting Up the Bracket Mounting Holes
Once your negative holder is assembled, attach the camera mount on camera and then position the negative holder on the mount so you can see the entire negative in the viewfinder and you can focus on it.�
Important: Try to place the negative holder as far as possible from your lens. I didn't and ended up with pincushioning problems.
Once you've determined where you want to attach the negative holder, mark the location and drill and tap holes in the mounting bar. Then drill out the bracket holes with a larger drill so the screws can pass through.
Square the bracket up to the camera mount then tighten the mounting screws.
Finally, remove the plastic parts and paint all the metal parts flat black to minimize light reflections.
Step 6: The Almost-Final Product
At this stage, the fixture is assembled and is almost ready to use.�
The large binder clip provides a quick and easy means of securing the hinged diffuser sheet. The small binder clips are what will eventually hold the light shield to the assembly.
Unintended side benefit: I was going to cut off the part of the camera mount that projected beyond the negative holder but I was lazy and left it long. I later found that when I opened the diffuser sheet, the extension supported it perfectly and reduced stress on the hinges.
Step 7: Making the Light Shield
The light shield eliminates extraneous reflections from the back and sides of the camera. The raw materials I used for my light shield were some re-purposed cardboard and duct tape.
The light shield needs four pieces of cardboard:
Cut two pieces 6" square. These are for the top and the bottom.
Cut two pieces 4" x 6-1/2". These are for the sides.
You will cut each of these pieces into a trapezoid, tape them together and mount the finished assembly on the negative holder with the small opening for the camera lens.
Step 8: Shaping the Top and Bottom Pieces
On one edge, mark the center (at 3") and from there, make a mark 1-1/2" out on each side.
Then, make your cut from the corner at the other end to each of the marks.
Step 9: Shaping the Side Pieces
On one edge, mark the center (at 2") and from there, make a mark 1-1/2" out on each side.
Then, make your cut from the corner at the other end to each of the marks.
Step 10: Assembling the Light Shield
Use duct tape to assemble the light shield.
Make sure the extra material at the large ends of the side pieces are protruding beyond the edge of the light shield.
Bend the extra 1/2" of the large end of the two side pieces out to create the "ears" used to attach the light shield to the negative holder.
When assembled, the large opening of the light shield will mate with the negative holder and the small opening will extend to cover camera lens.
Make sure that after it's assembled, the opening at the large end is smaller than the diffuser sheet - you want to keep all extraneous light and reflections from getting to the camera.
Mount the light shield to the negative holder and then mount your camera onto the fixture (not shown here - hard to do with only one digital camera.)
Step 11: Copying a Negative
When copying negatives, the best method to light them is to place a light source to each side of the negative, shining in towards it at a 45 degree angle. You don't want the light shining straight in towards the camera because that will create a hot spot.
Be sure to configure your camera to record the images as black and white and to compensate for the light source (natural, incandescent, fluorescent).
The picture below is an un-retouched image of the negative and holder taken with my lens zoomed to it's widest setting. I shot it this way so you could see how the diffuser sheet completely covers the light shield opening and how the light shield blocks out all extraneous indirect light (you can see a bit of the light shield around the edges).
Also note that the negative suffers a bit from pincushioning, but it's not bad - the end result is quite good and completely exceeded my expectations.
Step 12: Conclusions
The final test is in a direct comparison between a scanned print and its photographed negative.
Superficially, the scanned print actually looks pretty good, but that's primarily a result of some post-scan processing. The difference is in the details. Zoom in to each and you can see a dramatic difference in quality and resolution.
First Positive - Scanned Print at 300 DPI
Second Positive - Scanned Print Detail
Third Positive - Photographed Negative at 4MB Pixel Resolution
Fourth Positive - Negative Detail
What would I do differently next time?
You can see that the negative suffers from pincushioning. This is probably because I've placed the negative holder too close to the lens. The solution would be to place the holder further from the lens.
The camera mount screw that I liberated from my old flashgun works well - it holds the camera perfectly in place. But, I also use it to mount the whole assembly onto my tripod. As a result, everything is completely unbalanced when on the tripod. The simple solution would be to find the center balance point on the mounting bar and drill and tap it to accept the tripod mount directly.
Even though I painted the interior of the light shield flat black, you can see that it still reflects some light. A possible solution would be to glue black cloth or felt to the interior to try and reduce extraneous reflections.
Another approach to copying a negative would be to straighten out the negative and center it and then zoom in to remove all the other external influences right in the shot. I've since copied about 300 negatives and have found that trying to get them exactly centered and positioned is a very time-consuming and often frustrating process, so I've taken to just dropping them in place and taking the shot then make all the adjustments and corrections later on in my computer.
The diffuser sheet could use some centering marks to help pre-position negatives.