How To Digitise 35mm Slides and Negatives

example of a scanned image Introduction
If, like me, you started your photographic journey shooting 35mm film, then youíve probably got an archive of negatives and transparencies that you donít do a lot with. Perhaps some of those shots are really good and youíd like to share them online or maybe even produce some prints. Itís frustrating to have these images and not make the most of them so Iíve set about digitising part of my archive to bring it into the 21st Century.

In the past Iíve paid professional services to scan my transparencies and negatives which was fine but I only wanted my older portfolio images at the time which left me with lots still to do. If I was to scan many of my images Iíd probably look to buy a dedicated device as a pro service wasnít especially cheap but as I only want to do this every now and again I thought Iíd see if I could do this with some of the kit I already have. In the end I was able to get great images using my ad-hoc approach. Here you can see an image of a motorcycle racer. This is an example of an image I copied using my method I describe below. Lets take a look at how I did it.

The Gear
What I do is photograph the 35mm transparency (or slide), so I have created a setup that allows me to fill the frame with the slide and light it from behind. Lets breakdown the components of the gear and why theyíre important.

Camera
I used a full-frame Canon 5D, which has a sensor of almost exact proportions to match the slide which also gives me a decent image size at 5760px x 3840px. After taking the image, thereís normally a little cropping to do but Iím still left with a huge image to work with and thatís useful. Being able to change lenses meant I could choose the optimum lens to work in this scenario. I canít see any reason why most interchangeable cameras wouldnít work in this set up.
Extension Tubes
Tubes are really the key to a successful copy. They allow the lens to get right up to the slide, only about 2cm, filling the frame and still maintaining focus. Without tubes, the focus distance is too far away to fill the frame with anything useful. The type of tubes I have maintain all of the electronic contact with the lens too. I used a 21mm tube and a 31mm tube together.
Lens
I use the Canon 50mm F1.8, a really sharp lens that works very well with the extension tubes nicely filling the frame with the slide. The 50mm gives a quality image and copying like this needs the best image reproduction possible. Amazingly this lens is one of the cheapest we can buy and considering the quality it offers, Iíd say it was a worthy investment, not just for reproducing slides but general photography too.
Tripod
The camera has to be rock-solid-still to get the best chance of taking the highest quality, sharpest image possible so I needed my tripod. Thereís no chance of hand-holding the camera to do this type of work. Why that is will become clearer when we look at the technical side of the image later in this article. I use a Manfrotto tripod as itís well-made and very sturdy but there are many tripod manufacturers out there. If you donít have a tripod I imagine this setup could be arranged such that the camera was held steady enough but it might be a little fiddly. However, when needs must..
   Lights
My room set up was lit by natural light and diffused through a curtain but the main light to illuminate the slide was placed behind it. I used an LED light you can buy from Amazon or maybe even your local hardware store. I used this particular style because it gives me a long, top-to-bottom, left-to-right even light across the back of the slide and which is close to daylight colour temperature. There are a total of 72 LEDs which you can see in the image.
In my earliest test shots, the individual LEDs could be seen through the slide so I diffused the light by placing a piece of A4 paper in front of it. However this wasnít quite enough so what I did during the exposure was hold another piece of A4 in between the diffused light and the slide. I also moved it in a circular motion to break up the light further. This worked really well and made a massive difference to the quality of the light illuminating the slide. You can see in the set up image that the slide is about 10 cm in front of the backlight.
Holding the slide still
I had a big clip which gripped the slide very well. It was a bit fiddly to align the slide in parallel with the front of the lens and to then find the focus. If I was to do more than the occasional copy Iíd look to find a better way to hold and fix the position of the slide in front of the lens.
Focus
To focus I move the slide back and forth rather than adjusting the focus on the lens. Unusual I know, but at these close-focus distances, this works best for me. The 5D has an option to use the screen on the back of the camera rather than the viewfinder. I can then use the zoom preview option that magnifies the image x5 and x10. Plenty of zoom to nail the focus.
Air Blower
I used an air blower to blow off as much dust from the slides as possible. Even after doing that I still had to edit out a lot of bits in post-processing. Itís amazing how much stuff there is on the surface of the slide that isnít visible to the naked eye.

Thatís all the gear I used to capture the image. Lets now look at the technical side of the process.

setup for the transparency and negative copy The Technical Stuff
ISO
In order to get the best quality reproduction with the least noise, I selected the lowest ISO I could use, 100. Because the camera is mounted on a tripod, why would you use anything else? Of course the final image will only ever be as sharp as the original slide, so if thatís not sharp then the digital copy wonít be either.

Exposure
In the example image you can see here the exposure was F16 at 13 seconds. The aperture gives me lots of depth-of-field, although, working at such close-focus distances, that depth-of-field is really quite shallow, probably measurable in millimetres. However as Iím photographing something flat, thatís not too critical. It is however important to ensure the slide is held parallel to the lens.

13 seconds is a long exposure time and explains why I couldnít hand-hold the camera. Mounting the camera on a tripod meant I could use an exposure that was as long as necessary. Itís worth noting that the camera can still be subject to the tiniest of movements and these will ruin the exposure. Whilst the shutter is open Iím not moving around the camera, Iím completely still. If your room has a wooden floor, then that will be important.

RAW
I shoot RAW all the time and these images were no exception. RAW gives me the greatest flexibility when working on the image in post. If I shot to JPGs then so much of that is fixed and not easily changed. The JPG starts life as a compressed file so already loses some useful information. The RAW file captures everything with no loss at all.

I used a flat profile with low contrast and sharpening too to give me more latitude when working on the image in post. The default profiles in the camera are set to a higher contrast and add sharpening. However as Iím shooting RAW this is not an issue. If I was shooting JPG then the profile would be important.

Reducing Vibration Even More
Because my DSLR has a mirror, I can lock it up before the exposure starts which lowers any vibration risk. Because pressing the shutter always leads to a little vibration in the camera, I make use of the self-timer. This means the exposure doesnít start until 9 seconds after I pressed the shutter button, plenty of time for the camera to stop moving. If I wanted to be even more cautious, I could have used a remote release and then not touched the camera to begin the exposure at all.

crop of copied image at 100% 35mm Negatives
My negatives are in stripes which I havenít been able to copy without cutting out the negative I wanted and mounting it in to a slide holder. If I was to do more of these Iíd probably look to find a better solution to holding the negatives. After I've scanned a negative I have to add one extra post-processing step that I don't do when scanning transparencies, I have to invert the colours. This takes those 'negative' colours and reproduces them 'positive', in the correct colours.

Post-Processing
The image capture is only half the story. Thereís a lot of work to do in post to get the best out of those copies. To start with thereís all of the dust and marks to remove, to crop out any parts of the slide holder I might have included, to ensure white balance is accurate and then to add the contrast, colour and any sharpness. I try not to sharpen too much as this introduces sharpening artefacts that spoil the quality of the image. I always examine the image at 100% size when making any changes like this to see how it affects the quality. Some of these issues are never visible when looking at the photograph at smaller sizes.

Conclusions
Iíve been really pleased with how these slide copies have turned out. The reproductions are of a high quality and easily good enough to share online. Looking at the cropped section at 100% we can see just how sharp that is which for me bodes very well for getting great printing results at A4 and maybe even A3 if the original transparency or negative is sharp enough.

All images © Peter Hatter
Article Date - August 2017

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