4 ms·

From the linked 'seeing yellow' site: "They are present in both color printers and copiers but do not show up in pages printed in black-and-white mode."

• msandford 12y ago
  Because you can't print counterfeit currency with black and white, which is ostensibly the reason the whole thing got started.
  • arobertson 12y ago
    Couldn't you replace the black ink with green ink and then print in "Black and White" mode?
    • msandford 12y ago
      My guess is that you wouldn't get the shades right. Maybe with a lot of trial-and-error, but at some point it's easier to just make some printing plates and go that route. Either way the paper is the real problem.
  • akallio9000 12y ago
    So you could substitute green ink in the black ink container?