Ooh, I really like the idea of soaking the parchment in various potions! Or perhaps it could be added to the ink? I hadn't thought of that sort of thing. Thanks!
I also quite like the idea of the Impervius and the stealth one. Impervius is something I can see them adding after the map has been finished as one of them realises it could get wet/it does get wet or leaked over.
Thank you very much for your ideas! If anyone else has any, it'd be great to hear them.
Marauder's Map Creation
What sort of spells might the Marauders put on the Marauder's Map? I'm writing a Marauder fifth year fic, and since it's got their nicknames based on their Animagus forms, it might have been created in this year.
I was thinking perhaps a form of that Homenum revelio spell as it reveals other people's presence, and maybe a Protean charm as well, but are there any other spells that could have been used on it?
I'm not sure if this goes here, or in the Plot-Potion forum. Feel free to move it, mods, if you think it belongs over there!
Oh, I like this question
Just from trawling through the HPL of spells, I'm thinking...
Impervius - The map would need to be waterproof so they could use it outside, and also since Peeves has a fondness for water balloons. Also to avoid ink bottle smashes in school bags.
Maybe Point Me? - The compass spell (or a varient of it) could have been used to let the map keep track of movements and directions?? (maybe not)
The spell that is used to revert Animagi to their origional form? - With a large number of Animagi in the castle at the time, perhapse the spell was used so that the map could assign human names to the animals?
Stealth Sensoring Spells - like the ones placed by Umbridge on her office to detect anyone breaking in. Maybe used so they could find one another even when using the cloak?
Maybe it could have been dunked in a potion such as veritiserum, as "The map never lies." If it was possible to maybe soak the parchment with the potion and then dry the potion on it (could you use an Everlasing elixure, mentioned, but not explained in HBP), before drawing the map, perhapse the potion's effects could be made to last forever, as a dried potion would combine with the paper and not come out (like a dye).
Then other potions could be possible too, like the potion used to animate Colin Creevey's photos :)
That's all I could come up with. If I think of anything else, I will edit it in.
Sarah, I don't know if this helps, but in my James/Lily fic I have Remus use the Sorting Hat to get all the names to match the people. Only with, say, Squibs and Muggles, would it not work, as of course they haven't attended Hogwarts. Of course, then there's the issue of people from other schools (I don't know if Krum or Fleur ever appeared on the Map) but that could be remedied by the Sorting Hat being...connected to the other schools somehow? Then again, I don't know if the Map actually recognised people like Krum or Fleur, but if it did and I missed it, I suppose it wouldn't matter about other students.
I don't know if this is of any use, but I hope it is!
I can see them using a variation of the Trace / a tracing spell to assign the names to people and see where they are. It's quite possible it was entirely illegal - I mean, I can imagine it being an issue of privacy - but since when do the Marauders really care about rules?
You can also make up a few spells, as I'm sure the books only scratched the surface of the spells in existence in the Potterverse. Also, I get the feeling that any complex enchantment is more than just casting a bunch of spells on something; I think it'd require creativity - alteration of existing spells, careful manipulation to get them to work together they way you want them to or even invention of new ones.