As you may recall, I began the Ink Spots series in early December with a selection of blue fountain pen inks (see "Ink Spots"). At the end of December I expanded the test by adding a selection of reds, oranges and browns to my test window (see "Roses Are Red"). And this week I'm rounding off the test selection with test panels of greens and purples -- two of my favorite springtime colors!
The blues have been in a window with northern exposure (for the most consistent, indirect daytime light) continuously for 17 weeks (since December 3) and -- given that all of the inks tested consist of dyestuffs (which are usually thought of as far less permanent than pigments) -- and must say that I am quite pleased with the results.
All of the blues tested experienced some loss in intensity or brightness during the test. Two inks (Sheaffer Blue and Pelikan 4001 Blue) experienced some fading, while Pelikan 4001 Turquoise and Sheaffer Peacock Blue actually appear to have darkened in value.
Conclusion -- given that I have run similar tests on ball point and roller ball inks only to have some bleach out completely over the same time period, I find all of the inks tested to be quite acceptable for both letter writing and journaling applications, and for the creation of artwork intended for reproduction. Since most journalers do not intend for their work to be exposed to light on an everyday basis, any of these inks should (I think) be expected to last at least as long as the paper their used on.