Talk:Invisible ink

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No, invisible ink pens do tend to have two tips, one for encoding and one for decoding. I think the cover message is typically done with another pen. --Daniel C. Boyer 16:38 22 Jul 2003 (UTC)

Contents

[edit] IUPAC spelling

Multiple changes of sulphate to sulfate are a BE to AE conversion, which WP discourages. WP policy is to let BE and AE flourish. Probably should be reverted. ww 15:57, 19 Jul 2004 (UTC)

No, it's a conversion from the old, archaic spelling, to the spelling recommended by the IUPAC.
Darrien 00:13, 2004 Jul 20 (UTC)
And colour -> color? Never mind ;-) — Matt 00:32, 20 Jul 2004 (UTC)
Considering colour redirects to color and the MoS says: "Each article should have uniform spelling and not a haphazard mix of different spellings (it can be jarring to the reader). In particular, for individual words and word-endings. For example, don't use center (American) in one place and fibre (British) in another".
If it makes you feel better, the IUPAC recommends Aluminium and Caesium, so you Brits have two out of three. Humor also redirects to humour.
Darrien 01:40, 2004 Jul 20 (UTC)
Oops, I was just joking about "colour" -> "color"; sorry to have put you to the effort of digging out the Manual of Style ;-) I'm curious; is using IUPAC names now official policy on WP? — Matt 02:07, 20 Jul 2004 (UTC)
It's not an "official" policy, yet. It's more of an unwritten rule that anyone who contributes to chemistry related articles uses the IUPAC spelling. We've never had a problem with it yet, though I'm going to suggest it become an official policy to avoid disputes.
Darrien 05:13, 2004 Jul 20 (UTC)

[edit] Picture

Can someone post a picture of invisible ink? Maybe an animated gif of invisible ink in action. Such as: the application, fading, fading, fading, gone. Wuffyz

But that isn't how it works. Most if not all invisible inks are already invisible, or very nearly so, when applied. There is nothing to photograph but a blank piece of paper. Possibly you could do your animated gif of ink re-appearing when the developer is applied, but in most cases, the process is practically instantaneous. One possible exception is heat sensitive organic inks that "develop" by charring slightly in heat. Very careful regulation of the heat source can drag the development of these inks out over a few seconds. Possibly someone might like to make an animated gif of that? The other thing you could do, perhaps, is slowly spray reagent across a paper to bring out the message a few letters at a time. -- Securiger (talk) 01:47, 24 March 2008 (UTC)

[edit] Disappearing ink redirects to invisible ink

Disappearing ink redirects to invisible ink, and this seems not correct since the target of invisible ink is to make the message readable for the trained person, however the target of disappearing ink is to make the message visible during the creation and as long as possible (several days possible) after, but to become as unreadable as possible then.

I agree. I suppose they were merged because the disappearing ink paragraph is a stub, and they are somewhat related in that they are both inks with time varying degrees of visibility. However those seem like weak reasons to unite such different topics. Maybe they could both be covered in a single "time varying pigments" article, but unless such an article is created this paragraph should probably be split off. -- Securiger (talk) 02:06, 24 March 2008 (UTC)

[edit] Yes & Know ink

What ink do they use to print "Yes & Know" books ? They are revealed with a felt-tipped pen, that contains vinegar. Also, the ink printed on the paper becomes visible after many years (when the book gets old, and hasn't been exposed to the vinegar yet.

PS: When the black part (heated) of a piece of thermal paper comes in contact with vinegar/vinegar fumes, it goes white/clear. Why? How can we use that to our advantage? - Joshua Hrouda, NSW, Australia

[edit] Chemical reactions not just acid base

Our article used to say:

The invisible inks which depend on a chemical reaction generally depend on an acid-base reaction (like litmus paper) similar to the blueprint process.

I changed this to:

The invisible inks which depend on a chemical reaction may depend on an acid-base reaction (like litmus paper), reactions similar to the blueprint process, or any of hundreds of others.

There are several reasons for this. First, of our list of 15 examples of chemically developed invisible inks, only 3 use the acid-base reaction. Secondly, although 3 of our examples use a reaction similar to the blueprint process, this is not an acid-base reaction as implied by the original wording. Thirdly, there are many, many reactions which cause chemicals to change colour, and (as implied in the list of ideal properties) relying on any specific reaction is not a good idea. This is supported by our example list, in which several different mechanisms appear. -- Securiger (talk) 02:21, 24 March 2008 (UTC)