Short answer
Most colour photographs are chromogenic: their image is three layers of dyes — yellow, magenta and cyan — formed during processing. Those dyes fade in light, and unusually for any art medium they also fade in the dark, at rates set mainly by temperature, while the white areas develop a yellowish stain. Because the three dyes fade at different rates, prints drift in colour rather than simply getting lighter; cold storage is the one reliable way to slow it.
In a chromogenic print or film, each of three light-sensitive layers responds to one part of the spectrum. During development, oxidised developer reacts with colour couplers built into each layer to form dye: the blue-sensitive layer forms yellow dye, the green-sensitive layer magenta, and the red-sensitive layer cyan. The silver used to capture the image is then bleached away, leaving only dyes. Those dyes are organic molecules chosen for colour and processing convenience, and their stability has varied enormously between products and decades. Other processes — dye transfer, silver dye bleach, instant prints and, later, inkjet — use different dyes or pigments and age differently, which is why identification is the first step in caring for a collection.
The Canadian Conservation Institute points out that dyes in colour photographs appear to be the only materials in a visual art medium that fade appreciably in the dark. Dark fading is driven chiefly by temperature and, to a lesser extent, humidity. Henry Wilhelm's long-term tests distinguished it from light fading: in dark fading, highlight detail is kept but the whole image shifts in colour as the three dyes fade at different rates, worsened by rising yellowish stain; in light fading, the lighter tones wash out first. A single dye can behave differently in the two regimes: in some Kodak Ektacolor papers the magenta dye was the most stable in the dark and the least stable on display. Wilhelm also records that Kodacolor prints made from 1942 until about 1953 have all turned orange to some degree, whether or not they were ever displayed.
On display, most chromogenic prints fade primarily from light. CCI measures a photograph's life by the limiting dye — the time until the weakest dye has lost 10% of its density — because once one dye goes, the image goes off-colour. Its guidance keeps vintage colour prints below 50 lux for display periods of six to eight weeks, and allows modern prints, made from the mid-1980s onwards with more stable dyes, up to 300 lux for several such periods. It advises avoiding the ultraviolet from fluorescent lamps. The table converts those display periods into light doses and compares them with CCI's high-sensitivity category, to show how quickly even careful display adds up for older prints.
Because dark fading is chemical, cooling slows it dramatically. CCI recognises cold storage as the most effective preservation measure for large collections and notes that storage below 0 °C extends longevity considerably, at about 25 ± 5% relative humidity and never above 60%. Wilhelm recommended −18 °C (0 °F) and 30% RH for valuable colour negatives and transparencies, and institutions such as the Library of Congress moved colour collections into humidity-controlled cold storage. For a family collection the practical version is modest: keep negatives and prints in a cool, dry, stable room — not a loft, garage or cellar — in suitable enclosures, and digitise important images while their colours are still good.
| Display (CCI guidance) | Dose per 6–8 week period (8 h a day) | Periods to a just noticeable fade if high-sensitivity |
|---|---|---|
| Vintage colour print, below 50 lux | 16,800–22,400 lx·h | 10–179 |
| Modern (post-1985) colour print, 300 lux | 100,800–134,400 lx·h | 2–30 |
Why: Their dyes faded unequally in warm storage, and the least stable dye sets the cast.
Fix: Digitise and colour-correct copies; store originals cool and dry to slow further change.
Why: Light fading attacks highlights and lighter tones first.
Fix: Display copies, not originals; if originals must be shown, keep them out of direct light and rotate them.
Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.
FactStrong evidence
Dyes in colour photographs appear to be the only materials in a visual art medium to fade appreciably in the dark; longevity is measured as the time before the limiting (weakest) dye has lost 10% of its density.
Source: Care of Colour Photographic Materials — CCI Notes 16/5
ConventionStrong evidence
CCI recommends storing colour films and prints below 0 °C at 25 ± 5% RH, never above 60% RH, and describes cold storage as the most effective preservation measure for large collections.
Source: Care of Colour Photographic Materials — CCI Notes 16/5
FactModerate evidence
In dark fading, highlight detail is kept but the image shifts in colour as the three dyes fade at different rates, with increasing yellowish stain; in light fading, lower densities and highlights lose density disproportionately. In some Ektacolor papers the magenta dye was the most stable in the dark but the least stable in light.
Caveat: Product-specific findings from tests published in 1993.
ConventionStrong evidence
CCI advises displaying vintage colour prints below 50 lux for periods of 6–8 weeks, and modern (post-1985) prints at up to 300 lux for several such periods.
Source: Care of Colour Photographic Materials — CCI Notes 16/5
FactModerate evidence
In chromogenic materials, the blue-sensitive layer forms yellow dye, the green-sensitive layer magenta and the red-sensitive layer cyan, and the silver is then bleached out, leaving an image of dyes.
Source: Chromogenic print
Reviewed 29 September 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.