The real-world atmosphere contains mixed gases that cause color fading. Ozone (O3), nitrogen oxide (NOX) and sulfur oxide (SOX) must all be considered, therefore, as factors that effect image permanence.
With the combination of Canon's new dye ink and Photo Paper Pro, image permanence of 10 years is achieved in a mixed gas test environment.

<Criteria for estimation>
Estimated gas fastness is made under the following test conditions: Temperature (24°C) and humidity (60% RH) are controlled in an environment of mixed gases of O3, NOX and SOX. The ratio of the gases is typical to indoor air composition (O3: NOX: SOX = 3:19:1) with 100 times concentration in order to accelerate color fading.
<Criteria for estimation of print longevity shown above>
Estimates for image permanence are made using the Wilhelm Imaging Research, Inc.endpoint criteria "WIR Visually-Weighted Endpoint Criteria Set v3.0" as follows; Samples are printed with an optical density of 1.0 and 0.6 (each black, cyan, magenta, yellow)by default printer driver setting of each media.
The point where monochromatic/ reflective optical density shows loss of 20-35% (figure set repectively for each color, starting density of 1.0 and 0.6).
The point where the difference in color balance of yellow, magenta and cyan (each component in composite black)reaches 12-18%.

<Making your printed images last longer>
Light, environmental gases, high temperature and humidity can accelerate color fading. When displaying your photographs, avoid high intensity lighting and use glass-filtered frames. Photos stored in the dark, using archival quality albums or storage materials, will tend to last longer than photos that are exposed to light. Avoid high temperatures and high humidity to promote the image permanence of your photos.