Why do photos change colour?
Photo fading is as old as photography itself. Put simply, a colour photograph is created by applying 3 layers of colour to a supporting base (usually paper). These colours are blue (cyan), red (magenta) and yellow (yellow), which are applied on top of each other and thus create the colour variety of a photograph. The colour layers react differently to light and UV rays, which results in fading.
The colours are chemicals that slowly decompose over time. This decomposition shows itself mainly through two effects:
- General loss of detail (sharpness of edges)
- Change in the colours of the photos
Since the blue colour is more likely to age and fade than the other colours, the photos usually appear redder/browner than they originally were. This process also happens in complete darkness, so it doesn’t help to store the photos in a box. However, impacting light/UV rays accelerate this effect considerably.
Moreover, insufficient final rinsing during chemical development means that residues of the chemical development process are not sufficiently washed out of the paper. These chemical residues have a high pH value (=acidic) and destroy the three ink layers over time.
The liquid from the final rinse (=stabilising bath) had to be disposed of as special waste – which caused high costs. For some photo labs, this was a way to save a lot of money by reducing this rinsing and thus also reducing the waste chemicals that had to be disposed of.
Saving faded photos
Photos on paper, like negatives and slides, permanently change their colours – even if they are stored in the dark.
What can be done if the photos have already faded?
Scanning alone is not enough, as it only freezes the current state of a photograph. If damage has already occurred, these photos must be digitally reworked. Negatives, slides and photos, that are digitized by us, are individually checked by our staff and optimised in brightness and colour.
If the colour change is not too severe, it can often be reversed. If the change is too intense, however, an improvement can still be achieved or at least the current state is “frozen”.
What can be done to slow down the process of photo fading?
Although most photos are already likely to show colour changes, some measures can extend their shelf life:
- Store your photos in a cool place.
Low temperatures have a positive effect on the stability of chemical compounds. Therefore, choose a cool place for storage if possible. - Store your images in a dry place.
A relative humidity of 30% is considered optimal. However, this is not easy to ensure (a commercial freezer has a relative humidity of 60%).
Avoid cellars, sheds, attics or other places where temperature and humidity are subject to large fluctuations!