Black and white photographs shot on film and processed in a ‘wet’ darkroom don’t fade or degrade. They may have been stored in a shoebox for sixty or seventy years. Yet they are still likely to be as clear and unfaded as they were the day they were put away.
Of course, they may be creased or they may have been handled badly. They may have been rubbed against other photos, or they may have been kept in a damp place.
But if they were put away carefully that’s all the protection they needed.
That’s because the image in a black and white photograph is made of very stable silver compounds protected by a gelatine layer on fibre-based paper.
Printing Black And White Photographs In The Darkroom
The process for developing film and printing it in a ‘wet’ darkroom is more or less the same process as that from seventy or eighty years ago.
That process is straightforward shine light through the film negative onto the paper to produce an image. Use an enlarger to focus the light from the film negative and to magnify the projected image to the desired size.
The image that is cast onto the paper is ‘latent’ or hidden until it is developed in various chemicals.
First the exposed paper is put in a bath of liquid developer until the image appears. Then the paper is put in a bath of liquid ‘stop’ that stops the developer reaction. Then the paper is put in a bath of a third chemical to fix the image.
That’s it, and the whole process takes just a few minutes.
The paper is made of several layers. At the base there is the paper itself. Then there is a thin layer of silver compound where the photograph is developed and fixed. And on top there is protective gelatine layer. Do it right and the photograph will remain stable for upwards of one hundred years.
Why Photographs Fade: Incorrect Processing
If black and white photographs fade it is probably because they were processed incorrectly.
For example, the chemical that stops the reaction may have become weak or exhausted so that the development carries on slowly over the years and darkens the photograph.
Why Photographs Fade: Resin-Coated Papers
When plastic resin-coated papers became available for the amateur market in the late twentieth century, new problems arose. Traditional fibre-based papers used barium sulphate as the white base. Resin coated papers used titanium dioxide.
And the problem was that the titanium dioxide in the paper reacted with even very low levels of light to produce peroxides that oxidises the silver and makes the photo darker over time.
So resin coated prints from only a few years ago are subject to problems to which traditional fibre-based prints are immune.
What we know from all of this is that the stability of the image depends on the materials that the image is made from and from the paper on which the image is made.
Colour Photographs from the 1970s
The chemicals in colour prints are clouds of coloured dyes and silver compounds set in an emulsion. The dyes are activated by light, and when the process is finished there is no silver left in the image and only the dyes remain.
Colour photographs were, of course, introduced to the consumer market much later than black and white photographs, and the early dyes were not stable. They reacted with sunlight, with each other, with the paper base, and even with chemicals in the albums in which they were put. That’s the reason why early colour photographs fade.
Some colour photographs from the 1970s are now just a pale washed-out smudge.
Thankfully, the dyes in modern photographs have archival stability to rival black and white photographs.
Why Photographs Fade: Sunlight
That is not to say that colour photographs are immune to deterioration, and it pays to know what the biggest risks are to the stability and vibrancy of colour photographs.
There are two ways of preventing sunlight damaging a photograph. The first and obvious one is to hang the photograph out of direct sunlight. The second way is to protect the photograph with a sheet of glass that has a UV filter within it.
That is an expensive option and there are other downsides, because the colours of the print may look somewhat muted behind UV glass. And of course, many people don’t want to put glass over a photograph at all.
Why Photographs Fade: Chemicals
Cigarette smoke damages prints. That’s an easy one.
If the photograph is mounted in a frame then the mounting board itself can attack the print. The board may be made from wood pulp that contain acids that can cause it to turn yellow and eventually destroy it.
A professional picture framer will know this and will use an acid-free mounting board. These boards are either made from materials such as cotton rag that do not contain acids, or they have buffer chemicals in them that counteract the lignin acids in wood pulp.
Traditional Photographic Methods
In a ‘true’ photograph, the silver crystals or clouds of dye in the emulsion are activated by the light, and chemicals are used to develop the image and then to stop the development when the image is complete. The chemicals are in the paper even before the image is created in it.
Giclees, Inkjets, and Dye Sublimation Prints
These prints are not true photographs because there are no dyes built into the paper. Instead the printer reads the information in the digital file and uses that information to squirt colour dyes or pigments onto the paper. The paper is just a medium that accepts the colour put onto it.
Dyes are solutions of dye materials in water; which means that the dye is dissolved in water and the solution is squirted onto the paper and absorbed into it.
Pigments on the other hand are suspensions of very finely ground insoluble material that is suspended in water. The suspension is squirted onto the paper and the pigment lays on the surface of the paper rather than being absorbed into it.
Dye sublimation prints work by heating up and vaporising coloured dyes into the paper.
Dyes are not colour-fast and can fade within a matter of months. Pigments can remain light-fast for upwards of 100 years, and are now so stable that they are said to rival true photographs for archival stability. And why not, because pigments are precisely what artists have used for centuries, bound up in oil to create oil paintings.
The Photograph Of the Elephants
I took the photograph of the adult and two young elephants in South Africa. I shot it on a Nikon D500 digital camera with a Nikon 70-300mm f4.5-5.6E ED VR AF-P lens and processed it in Lightroom. I then converted it to a black and white photograph in Photoshop to use to illustrate the topic why photographs fade. If I were to have the photograph printed I would use a pigment-based method for longevity.
Why Photographs Fade: Today And The Future
It’s kind of funny that at the very time that we can produce stable colour images that are vibrant, the move is away from prints towards displaying on a computer screen. Will there be prints fifty years from now? Will people look at their walls and want a by print on it? Time will tell.