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Many of our customers have asked to see our internal data on "Fade Testing" for our archival inks. Permanence testing by Wilhelm or RIT is a long process. Our testing at RIT started in April 1999. The results are now available.

Many of the ink companies use accelerated test methods to determine the permanence or fade resistance of their inks. These accelerated tests are brutal compared to the RIT type permanence testing with fluorescent light. The objective of the RIT type test is to predict museum life. We are interested in knowing if we have an ink that will resist fading in all kinds of light, including sun light and museum or indoor light, and we need to know right away, not four months later or 50 years later.

Light (especially UV), causes the ink/paper system to oxidize. When ink is oxidized it fades. Light and humidity are the two main ingredients that cause inkjet prints to oxidize or fade. Heat, also plays a roll in accelerating the oxidation or fading. So our accelerated test method had to have all three elements to give us confidence that the results we achieve relate to what happens in the real world outside of the laboratory.

The Procedure -
So, here is what we do to determine fading or fade resistance. We submerse the inkjet print being tested into a 1% bleach and water solution. We time the length of exposure. Then we rinse the paper (both sides) with cold water to remove the bleach. Then we oven dry the paper at 140 degrees Fahrenheit until it is totally dry. When it is dry, we use a Minolta CR-300 Colorimeter to measure the fading that has occurred. The bleach provides the oxidation, the water the humidity and the oven the heat.

Delta E Data -
The colorimeter reads out in what is called "delta E" values. It is a complex measurement, too deep for our discussion here, that is used commonly in the measurement of color and color intensity. To give you a feel for delta E values, here is an example. Let's say that two squares of red are measured with the colorimeter. One has some fading, the other does not. If the difference between them is 3 or less, it is very hard to detect the color difference by the human eye. If the difference is 8 or greater, the color difference is very noticeable to the human eye. In between delta E values of 3 and 8 fading begins to become visible. A delta E of 15 or 20 would be considered major fading and anyone can see it. Take a look at the color charts at the bottom of this page to see some real delta E's. The delta E between the Epson Red (0) and Epson Red (10) is 47.2, the Lyson (0) vs. Lyson(10) is 26.2 and the MIS(0) vs. MIS(10) is 4.9.

Correlation with known inks and papers -
We selected papers and inks, that already have permanence data, to test along side our inks so we could correlate our accelerated test data with the RIT type data. By comparing the fading of the known inks against the fading of the MIS inks on a relative basis tells us how our inks will compare to the ones with permanence data. For example, if a paper and ink has an archival life rating of 50 years and during our accelerated testing the fading of our paper and ink is say, half the amount the rated paper fades, then we know that our paper and ink will have nearly double the archival life of the know paper and ink.

The Somerset Velvet Test -
We printed six blocks of color and a strip of black on a sheet of Somerset Velvet, Radiant White. We printed this three times using MIS Archival ink, Lysonic™ Archival Ink and Epson™ factory original ink. It was all done with the same printer, an Epson™ 3000. All the settings were kept the same and the print heads were flushed out with MIS cleaning solution before changing inks.

Then the accelerated testing was conducted as described above for four different exposure times of 10 minutes, 20, 30 and 60. Colorimeter readings were taken before and after the testing on each square of color. Actually we took 5 readings per square in different locations and averaged them together to get one reading per square. Then readings for each color (red, green, blue, cyan, magenta, yellow and black) were averaged together to get a single value for the given exposure time. The results are shown in figure 1.

Figure 1

It is quite obvious that the MIS inks did not fade nearly as much as the Epson™ or Lysonic™ inks. The raw data gathered for the graph is shown below. The MIS ink faded 5 times less than the Epson™ ink and 4 times less than the Lysonic™ ink, after 60 minutes of accelerated testing.

Figure 2 looks at the same data as a plot of fading vs. exposure time. The results show that the Epson™ ink and the Lysonic™ start to fade quickly, while the MIS inks fade much more evenly as exposure time is increased.

Figure 2

In Figure 3, we isolated the black ink results to get an idea how our quadtone inks will hold up under the accelerated test conditions. It is interesting to note that the Lysonic™ black fades faster that the Epson™ black. Both fade much more than the MIS black. The MIS black stabilizes after about 20 minutes and very little additional fading occurs.

Figure 3

The Lysonic™ yellow is rated by Wilhelm to be superior to the other colors, so we isolated the yellows and show the results in Figure 4. The Lyson and Epson™ yellows do show the best fade resistance of all the colors. However, when a shade of color contains their yellow, the other colors fade away first leaving a yellow cast to what is left. The MIS yellow fades at about the same rate as the rest of the MIS colors and does not produce a yellow cast on the overall image. It is interesting to note that the MIS yellow fades the least, and is still has over 3 times the fade resistance. (Please notice that the vertical scale has changed in Figure 4).

Figure 4

The Delta E Data
Below is the delta E data gathered during the testing process for the Somerset Velvet paper. We hope this data provides you with enough information to answer the questions you may have been wondering about. It certainly gives us the confidence to tell you that our Archival and Quadtone inks have fade resistance that is much greater than the Epson™ factory original inks and the inks of our competitor. In the next week or two, we will publish similar data for our Photo Glossy paper and for the Concord Rag paper.

The Color Data
After the tests were complete, the colors were photographed with an Olympus D500L digital camera using exactly the same settings and lighting for each color shot.  The colors were arranged on a color chart to visually display the fading that occurred for each inkset.   It is not meant to be highly accurate in terms of absolute color, because each monitor will display the colors differently.   However, for monitors with high resolution color it does show the relative fading that occurred from 0 to 60 minutes exposure.