Analogue Negative Film

to Digital Image Conversion

 

Converting your old negative film pictures to digital colour pictures by means of a compact, digital camera ?

Why, that's easy !!!

Just follow the simple steps below, and you will see.
 

 

   
   

1. Take a close-up picture of your negative:

     
     

2. Make a copy of your picture

- and save the original, digital picture in a back-up folder:

     
     

3. Rotate your digital negative copy using a horizontal or vertical line

(if appropriate for alignment)

and crop the picture leaving only the originally exposed negative:

     
     

4. Invert your digital negative.:

     
     

5. Fix the imbalanced colour levels by a click on "AUTOLEVEL":

Click on image to see the final result - or rather the result at this stage -

in better (19% of true size) resolution,

   
D O N E !
   
Is it really that simple? Basically, the answer is YES as long as you want to make quick and reasonably good looking digital copies of all your negative film in order to establish a digital archive where: 1) you can easily see, what you have in your analogue archives; 2) have them in sufficiently good quality that you can share them with others without too much embarrassment; 3) can pick-out those singular, precious pictures that deserve more attention and care. (There are still room for improvements to the picture such as White Balance, but we shall come back to that later).
   
Of course, things may not always go as easy as shown above and there are certain rules and tricks-of-the trade that should be learned first. So, on the following page, we shall have a look at a more "stubborn" digitized image that is not so easily balanced as in 5. above. At the same time, we shall learn what functions are available (or at least a few of them) for reproduction and enhancement of your valued old analogue film pictures.

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What went well - and why?

But first, let us examine why we had success in the example above, where so many appear to have failed or given up as judged from a search on the web. So, we shall take a closer look at the steps 1-5 in the example:

 
1.1 The set-up. Here the critical elements are  
 

a. Light source

 

Needless to say you need a uniform back-light. In my home-built setup I use a sheet of pure white plastic cut from an ice cream box as "primary diffuser" and (sometimes) a "secondary" pure grey diffuser from an old slide viewer (Agfa Gucki) of the hand-held eye-piece type.

You must also consider the colour temperature of your light source. In the picture above you can see that I have used a simple (and VERY cheap) 4.5 Volt 7-lead lamp. This provides, what we normally call a "cool" bluish light, but in a physical terminology, this light source has a high colour temperature. I also use a 12 Volt 30 Watt halogen lamp with some success, but mostly with a bluish glass as "secondary" colour filter. The reddish light from a tungsten lamp (we call it "warm", but the colour temperature is low) will increase your troubles in balancing the colour levels because negatives (usually) have the so-called orange mask that provides negatives with their distinct reddish hue. (See also below). Important to know is also that some lamps only emit light in a few, discrete wavelengths as is the case for modern energy-saving bulbs, fluorescent tubes and LEDs. Tungsten lamps have a continuous spectrum but a strong bias towards the red light.  Your light source should emit light that is well represented at  the reddish, greenish and bluish wavelengths. If you use daylight as source, you should go for the scattered light from the blue sky away from the (reddish) sun  or, even better, the scattered light from a slightly overcast but bright sky, (even higher colour temperature).

To the left, I have inserted a picture of my back-lit "primary diffuser" together with histograms  for all colours combined (Master) and each of the primary colours, red, green and blue. (distribution of levels, 0....255, over all pixels). As you see there is a fairly even distribution of all colours emitted by my rather primitive LED source.

And as practical experience has shown us in 5. above this suffices to bring our "digital negative" into a manageable area for further balancing and possible additional enhancements.

 
   
  b. Optics  
    If you use a compact camera with non-interchangeable lens you will need something "extra" to have your negative fill out the whole field of view in the horizontal dimension. Some cameras come with a macro or super-macro mode that will do the job for you right away, but take care: Some cameras do show a lot of distortion in macro-mode that you do not notice when you shoot an occasional small flower or insect but which may become very obvious and annoying when your subject is a whole building, landscape or similar. Try it out !

For my current compact cameras, I use either a 135 mm telephoto lens or an 80 mm lens from a slide projector as macro front lens. Both are from around 1950 found on flee markets (and thus, cheap). These were designed to provide large magnifications without distortion and without false colour fringes and they work in fact very well in my set-up. However, in order to avoid excessive vignetting your compact camera must have a good zoom - again, without distortions.

DSLRs have now become within reach (financially speaking)  for more amateurs, and such cameras can of course also be used for this type of work. An example of how one may set-up a DSLR for film and slide duplication is presented on the  Diaposítive Duplication Page,

     
  c. Camera controls and settings  
 
 

Olympus Remote Control RM-1

(How can any amateur photographer live

happily without such a handy gadget?)

You will want a camera that reproduces as faithfully as at all possible all the levels recorded in your original film. This means that you do not want automatic, aggressive post-processing. The post-processing must be done in sufficiently sophisticated digital imaging software. You may also refer to the Gallery Page for a slightly extended discussion on this subject.

Usually, you camera will do very well using the AUTO setting, but in difficult cases with very contrast images, under- or over exposed pictures and similar, the automatics of your camera may fail and full, manual control is in general most desirable. This is more so, as you may stop down your lens (to a higher f-number) in order to increase the sharpness in depth and thus, counteract smaller focusing problems.

In the set-up above, I have a high colour temperature but a low intensity light source, meaning that I need quite long exposure times. As mentioned above, I also prefer to stop down the lens and therefore, the camera must allow for long exposure time settings. I may need as much as 8 seconds of exposure time.

When you want to shoot a lot of pictures in the minimum of time. Here a remote control comes in truly helpful. Unfortunately, it appears that the trend is away from that useful gadget for compact cameras. If you don't have and cannot find a camera with this capability, you must rely on the self-timer which almost each and every camera has today. If not, find another camera.

Finally, if you want to shoot many pictures during a good evening's work, you should consider buying an external power supply for your camera. You will be using the LCD display constantly for a long period of time and that will drain your batteries

     
  d. The mount and light board  
    Nothing much to say her. Your own imagination and parts readily available control the design.

It should obviously not be too flimsy; with camera and extra lens it carries quite some load and - as in my case - long exposure times are often required. I built mine from the sliding rails for a drawer, available at the local lumber yard and parts from an oooold office desk lamp.

2.2 The negative  
 
 

Original negative (1991)

shot on Pertutz PR 100

Most negative film (but not all) have a layer of dye that when developed has a distinct reddish hue - this is the notorious orange mask. It is there to counteract inevitable impurities in the other colour sensitive layers of dye on the film. However, common to widespread belief, the orange mask is NOT the main problem in digital reproduction of negatives.

The orange mask is a monochrome colour and therefore, in principle, we just need one filter to remove its effects. In the wet darkroom we do this by means of coloured glass or gelatine filters - in theory just one filter for one specific brand (and batch) of film. In the wet darkroom we further use optical filters to compensate for colour casts (from different light sources) and simply to enhance certain colours to make the scene look "right" in the final picture.

In the digital darkroom we do the same. We use digital filters. More about that in paragraph 5 below.

The main problem with analogue film reproduction is that it is so good in respect of definition (speaking for negative film at least) while 8-bit digital colour pictures may have difficulties in reaching that same definition - and when it does, the "raw" pictures may look terribly wrong to our eyes. Again, the answer lies in the digital processing - not implemented as a standard algorithm within the camera but as a dedicated piece of work in the digital darkroom.

Needless to say, the limitations in definition implies that you can never "improve" upon an analogue picture through digital copying. But, as we shall see at a later stage, there may be details in the analogue picture that are not readily seen by the human eye but which may be made visible after proper digital image processing.

     
3.1 Rotating and Cropping  
    Noting much to add here. You should just go for software that allows for easy alignment through rotation using horizontal and vertical lines plus free rotation at any arbitrary angle. (That will also help you "save" pictures, where you have tilted the camera by accident during exposure).

Regarding cropping, just make sure that you software has easy settings for cropping to standard formats such as digital cameras (4:3) and standard photos (9:6) etc.

     
4.1 Inverting  
    This is as simple as can be. Any software that can invert colours (and most programs can) will do that in one and the same way. Maybe some have given up already at this stage? The pictures bluish-greenish cast could be even worse had I used another light source or had I used an indoor picture as example. But if you have understood a bit of the foregoing remarks on film, definition and levels, there is good reason to proceed.
     
5.1 Fixing and Balancing  
 
 

INVERTED "ORIGINAL"

AUTO-LEVEL

 

Most digital imaging software packages come with a suite of automatic operations for "enhancement" of your digital images. At the outset, you should treat these AUTO-FUNCTIONS with the utmost suspicion. It is as with the processing algorithms hidden inside your camera: They make some generalized assumptions based upon the contents (distribution of levels) of your image and then proceed with a number of standard operations en suite (mostly hidden to the user) trying to achieve what the designer of the software thought you would like to see as the final result. These standard functions may work well (sometimes) on slightly unfocused, slightly underexposed, slightly colour cast indoor pictures from aunt Audrey's 80 year birthday party (but sometimes they may also produce disastrous results !).

However, they were not designed for and nor do they normally work with such special applications as for example analogue film copying where the distribution of colour levels together with colour cast and white balance may differ substantially from what the software developer would think should apply for a digital photo taken under "normal" instances.

As an example, I show again the final picture from 5 (where I used AUTO-INVERT). Below, I have inserted similar results for the inverted negative in 4., using AUTO-ENHANCE, AUTO-COLOUR and AUTO-CONTRAST, as available and named in PhotoImpact 12. Other brands should provide similar functionalities.

Obviously, only AUTO-LEVEL works (at least for this picture). The others do not - and in other cases may decidedly degrade the picture even further. The answer is, (or so, I think), that AUTO-ENHANCE/ -COLOUR/ -CONTRAST have built-in assumptions as to what may need improvement in an ordinary digital picture and apply a number of modifications in a fixed, consecutive row. That simply doesn't work for the kind of imbalance in colour levels that we encounter here. You very rarely see this kind of blue-green cast in everyday photos !

The AUTO-LEVEL on the other hand is far more "clean". It only makes one specific assumption about the distribution and balance of the levels of colours that are already present in the picture and stretches the distribution of colour levels over the entire range in a more useful way.

How this is done in detail and why it works so well so often (at least in PhotoImpact), I cannot say. The assumptions on how to re-distribute the colours may be different in other software but here at least, it is a very useful application that may sometimes just do the job and, if not, point to what other routes for fixing that should be pursued.

 

 
     

AUTO-ENHANCE

AUTO-COLOUR

AUTO-CONTRAST

   
 

Should everything fail - and it so does from time to time - we are still on the right track and there are still additional (manual) means for reaching useable results and also for giving your picture that final, finishing touch. Things typically go sour for negatives taken on daylight film in artificial light; in extreme contrast scenes or under lightening conditions that produce severe colour cast.

In such events one will have to resort to additional techniques such as White Balance, Curves & Levels, Colour Cast and more. There are no text-book solutions, but problems in these instances are more or less the same as with less properly exposed or slightly deteriorated colour diapositives so, there will be some guidelines/inspiration to find if you vistit the following Diaposítive Duplication Page,

   
 

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Copyright © 2008 - Steen G. Bruun