'immortalising' ink on fabric

[Pleiades45]

DS had his taekwondo white belt signed by Jades Jones on Saturday. I gave him a black permanent marker to use.

Is there anything else I can do to ensure the longevity of the autograph?

Don't wash it

Try www.wikihow.com/Preserve-a-Signature-on-an-Article-of-Clothing

Or

www.ehow.com/how_2253121_preserve-autograph-clothing.html