[Daimyio]

Hey, i got a question and don't really know where to post it, but is there any fugitive pigment that would fade away completely after some time ?

[Enthalpy]

Invisible ink maybe?
https://en.wikipedia.org/wiki/Invisible_ink

In fact, invisible ink is more difficult than "fading away", since the ink is revealed under special conditions.

Also known are inks that are clearly visible at writing but fade away later.

UV light, oxygen from air could achieve it, or humidity, or CO₂ - to neutralize a base that colours phenolphthaleine.

Or your pigment could evaporate fully - not obvious, since long conjugated organic molecules aren't so volatile, and metallic ions neither. Evaporate a compound that colours an other one, like an amine and a pH indicator?

Or just a slow reaction among the pigment's component, but then the user would have to mix them just prior to use (at least, logically). Or a reaction between the pigment and the substrate.

[Daimyio]

I'm so glad you answered but i forgot to mention an important thing and it is that the colorant has to fade away after about 2 - 3 months.

[billnotgatez]

I'm so glad you answered but i forgot to mention an important thing and it is that the colorant has to fade away after about 2 - 3 months.

Is this taking place in sunlight?

[Furanone]

Perhaps not using salts or alkali to "fix" dye will have an effect of making the dye less permanent...

https://oecotextiles.wordpress.com/tag/reactive-dye/

[Daimyio]

I'm so glad you answered but i forgot to mention an important thing and it is that the colorant has to fade away after about 2 - 3 months.

Is this taking place in sunlight?

No it wouldn't be on sunlight most of the time.