GHL Blog Rotating Header Image

How to digitize your photo negatives: Interview with Mathew Waehner

Share Button
Mathew Waehner, head of the State Archives of North Carolina Photography Lab, scanning negatives on a special scanner.

Mathew Waehner, head of the State Archives of North Carolina Photography Lab, scanning negatives on a special scanner that uses a light to shine through the film.

October is doubly honored this year, being both Family History Month and Archives Month, and we’ve been thrilled to see so much buzz about preserving family history! One of the most common types of questions we see is how to digitize family materials, especially photos. In anticipation of this Saturday’s free Family History Fair in Raleigh, I sat down with Mathew Waehner, head of the State Archives’ Photography Lab, to talk about the ins and outs of digitizing photo negatives, and why someone might want to digitize a negative instead of its corresponding photo print. 

You been scanning photo negatives for the State Archives for a while, right?

Matt: Yes, I’ve been with the State Archives for nine years, film digitization is the number one thing I’ve done.  I’ve scanned over 100,000 historic negatives!

Lots of people are using their home scanner to digitize their old family photos and put them online. Can they also digitize negatives at home?

Matt: It is certainly possible to digitize negatives at home, but most scanners can’t handle negatives at all, and there are some really bad negative scanners at the low end of the price range  (there might be some good ones too).  A film scanner is a significant investment, and scanning film takes more time than prints.

What kind of special equipment do they need?

Matt: The main piece of special equipment needed is a film scanner!  Look for one that has an optical resolution over 2000 DPI, preferably around 4000. This is important because film contains microscopic detail, it is designed to be enlarged.  Scanners may advertise a “maximum resolution” higher than the optical resolution, but that is just extra data interpolated out of the optical resolution — in other words, the scanner makes up detail that it can’t see in order to reach its advertised maximum resolution. (High resolution is not important for print scanning, most prints don’t have much detail beyond what is visible to the naked eye.)

Also, look at the Maximum density or DMax of the scanner — a good scanner has a max density around 4, 3 is decent, and poor quality scanners don’t list any at all.  This is a measure of how dark of a negative the device can read.  Every print has a limited range of tones between white and black, but because negatives are designed to have light projected through them, they have a larger range of tones between white and black.  Originally, negatives were adjusted during printing, but now we do it digitally, and a scanner with a larger dynamic range enables much more adjustment.

Also, you will need gloves (cotton or nitrile), because touching negatives with fingers can cause permanent damage.

What difference in quality should they expect when scanning negatives vs. photo prints?

Matt: If you have a quality scanner, scanning negatives can always produce better results than scanning prints, as the negative is the original recording of the image.  The results can be better both in terms of detail and sharpness, and the negative also offers more room for adjustment of contrast and color.  Also, archival sleeves to house the negatives are a great idea. Other plastic sleeves aren’t bad but they will eventually degrade and stick to the film.  Glassine paper is acidic, so it should be replaced, or at least separated from the film.

Most people probably have 35 mm film at home, but what about people with other still-photography film formats?

Historic film negative formats

Historic film formats. Image source:

Matt: Yes, 35mm film was pretty standard for consumers starting in the 1960s, but there are many other sizes and shapes of film.  For one thing, slides and transparencies were very common for vacation photos and also for commercial use.  Most 35mm scanners can handle mounted slides.  In the middle of the twentieth century 2.25 inch roll film was common, it persisted longer in professional applications. The length of the dimensions of the exposure on the negative could vary.  Sheet film was common in the early part of the twentieth century, it can record an extremely high amount of detail.  You should check your collection before acquiring a scanner, if possible, to determine which type of scanner you need.

Do you have any tips for working with old or brittle negatives?

Roy Boshi, Photographic glass negative of a horse and carriage. Maybe a Collodion negative

Glass plate negative. Image source: Roy Boshi, Wikimedia Commons

Matt: Old film does need to be handled with care, but consider how much use it is if it isn’t scanned or printed somehow.  Best practice is usually to scan it at high resolution once at high enough resolution that it won’t need to be scanned again.  If you are working with glass plate negatives, brush dust off of them before scanning- they often have tiny sharp fragments of other negatives on them that can scratch film and damage your scanner.  You may encounter film that is bubbled or warped (google “Vinegar syndrome” for pictures), it scans surprisingly well.

Leave a Reply

Your email address will not be published. Required fields are marked *

This blog is a service of the State Library of North Carolina, part of the NC Department of Natural and Cultural Resources. Blog comments and posts may be subject to Public Records Law and may be disclosed to third parties.