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.)