Prior to the digital age, for pretty much every photograph printed, somewhere there’s a negative. Whether it’s your childhood photos or something produced by a Brownie in the forties, there was once a negative produced. On the other hand, the alternative to a movie camera on many a boring family vacation were slides — which consist of the developed positive film mounted in a little frame. In both cases, the fragile and tiny images are not particularly displayable without putting the originals at risk of damage, but they still represent the first-generation image, right off the camera.

Photography fans with a stash of negatives and slides used to rely on the skills of a talented photo-developing lab to produce prints and copies of their collection, potentially handing off some irreplacable images to someone who doesn’t understand the care required to ensure the aging images survive. Today, however, a regular PC and a cheap but specialized scanner can make digital copies of transparent negatives — which can be burned to CD and taken to anyplace that can do digital prints.

Prices have dropped to where a consumer-grade scanner capable of doing negatives can be had for around $100, but people’s accessibility to negative scanners have been limited in the past. Negative scanners were once quite expensive, and some would only accept one size of film — and people often didn’t know that many consumer-grade scanners actually have add-ons for scanning film. The key to scanning a semi-transparent medium, like a negative or slide, is ‘transmissive’ scanning. The usual method of scanning is like a photocopier, where the sensor that scans the page and the light source are on the same side — or ‘reflective’ scanning. The glossy coating of a negative makes ‘reflective’ scanning akin to flash photography in a mirror — lots of light, little image. ‘Transmissive’ has the light source behind the object to be scanned, like a movie projector, so the imaging sensor sees the image on the film, and not the film itself.

Many scanners have options for transmissive scanning, ranging from a small add-on that plugs in to the scanner and rests on the glass, to replacement covers for flatbed scanners. My scanner, a UMax Astra 4450 originally bought for scanning slide film, was specially designed with a transmissive light source built into the cover. It doesn’t span the entire scanning surface, so it comes with a template to help line up the negative. The 4×6 source in the scanner is large enough for all but the larger of glass negatives.

Having the light source on the back means that nearly any semi-transparent image can be scanned — glass negative plates, movie film, slides, large-format negatives. Anything that can fit in the scanner’s tramissive area will work.

Because of the wide variety of media, a little experimentation is needed to make sure it works. If you have any familiarity with developing black-and-white photos, using a transmissive scanner is the digital version of using an enlarger…and that always required a little trial-and-error to fine tune exposure and quality.

Much like an enlarger, you’ll need to do some calculation to get your image’s size correct. A scanner’s DPI, or ‘dots-per-inch,’ is a measure of image quality: the more ‘dots’ per inch, the better the print will be. For example, my 4 megapixel camera produces an approximately 400 DPI 4×6 photo. If I were to put a 4×6 photo on my scanner, and set it for 400 DPI, the scan should be of similar size and quality to my digital camera. However, do not forget that a negative is far smaller than the photo, while the scanner’s DPI is a measure of what’s actually being scanned on the glass. A 35mm frame is a little under an inch-and-a-half across, or 1/4 the width of a 4×6 photo. To produce a digital image of similar quality to a 4MP digital camera, the negative will have to be scanned at 4 x 400dpi, or 1600dpi. If you were to scan at 400dpi, you’d get a 400×600 image, which is far too grainy for anything but emailing or posting in a webpage. Scanning a 35mm frame at 600dpi or 800dpi should be the minimum level of quality to get a reasonable photo print, and most consumer-level scanners can do this or better. Don’t think that Photoshop can work magic: if the scanner was set at too low of quality, increasing the image’s size in Photoshop only makes the graininess bigger.

My examples are negatives from the 1930s in two sizes: 3-1/2″ x 2-1/2″ and 2-3/4″ x 1-3/4″. I’m scanning both at 600dpi, which should produce a relatively high quality scan, given the age and quality of the negatives. The negative is placed on the scanner flatbed, in the region of the template, the cover is closed, and the ‘transmissive-negative’ option is selected. When the scanner passes across the negative, taking in the light that passes through the negative, the software will invert the brightness, producing a positive image. If I were to scan a color slide — which is not negative — my scanner has the option to just scan, without inverting. Once I have the image in Photoshop, I can adjust and fine tune the levels and contrast to my tastes, and then save it. After I have my settings figured out to produce a good image, the process becomes quicker. Because I do the converting in the comfort of my home, the negatives are ar far less risk for damage or loss, compared to delivering them to a photo studio for enlarging.

Once you have the image scanned, the negatives can be returned to their acid-free, cool, dry storage, and you’re left with a high-quality digital version. Burn it to a CD, and even Wal-Mart can print them for you on high-quality photo paper. Upload them to Flickr and show off your collection. If your photos are family or historic, use them in a website devoted to the photo’s subject. These negatives and slides, once hidden away for their own safety, can now be reproduced and shared without putting them at significant risk of damage.

Short notes:

• Transparent images are scanned using a ‘transmissive’ technique, with the light behind the image. Scanners can be purchased with it built-in, or added as an option, depending on the manufacturer.
• DPI applies to the scanner’s surface, not the actual image. Calculate the quality of the print you’d like to make, and set the scanner appropriate for the negative’s size.
• Like hand-enlarged photos of old, some experimentation may be needed to get proper exposure, contrast, and color.
• With a little work, those negatives and slides can be shared without putting the originals at risk.

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Article Tags: Flickr, negatives, photograph, scanning, storage

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