When we were kids, my brothers used to talk about writing important things down in indelible ink. Of course back then I thought they were saying, “in double ink”, which sounded just as important, if you ask me.
You could say our ink is indelible. By definition, indelible is described as ink that cannot be erased or washed away.
This is a handy feature in a chart book. Water won’t rinse our ink off. Beverages don’t make it run. Sunscreen lotion or motor fuel wont smear the ink like on plastic charts. No need to carry around a grease pen, which always ends up on your clothes. You can write notes on our chart book pages with a pencil and then erase it without the ink underneath disappearing.
Speaking of disappearing, do you remember the secret codes that would only show up when you looked through red lenses? Ok so maybe I was the only weird kid, but what I’m talking about is this: It takes a while for your eyes to adjust to the dark again after turning on a bright light. Often airplane pilots and careful boaters will want to check their charts at night but don’t want to diminish their night vision by turning on reading lamps or flashlights. To get around this, a red navigation light is used to illuminate the cockpit. Regular red ink will “disappear”, but if a hint of blue is added to the ink during printing, it looks red-ish purple by day, and is visible under the navigation lights at night. This ink is referred to as aero-magenta, or what we call “red light readable ink”