TechWhirl (TECHWR-L) is a resource for technical writing and technical communications professionals of all experience levels and in all industries to share their experiences and acquire information.
For two decades, technical communicators have turned to TechWhirl to ask and answer questions about the always-changing world of technical communications, such as tools, skills, career paths, methodologies, and emerging industries. The TechWhirl Archives and magazine, created for, by and about technical writers, offer a wealth of knowledge to everyone with an interest in any aspect of technical communications.
Subject:Re: Invisible Ink From:Tom Mereen <tom -dot- mereen -at- ECTI -dot- COM> Date:Tue, 26 Jan 1999 14:28:47 -0600
Steve,
David Dubin's answer is the closest to the solution I used about 1993. I produced student documents for a training facility. We used a "non-reproducible blue" on 1/3 of the text so students could not reproduce the student manual when they got back to their home company. Unfortunately, I do not remember the color number.
I remember using a pencil with the same color in the 80's for marking up documents. You might call a local art supply store to see if they are still available and get the color number.
