I saw two Da Vinci restorations at the internet
Last Supper
Virgin on the Rocks
I dont know you but I find beatiful that faded , cracked , dusted old effect on Last Supper and thick brown shadows of wrong varnish applied 60 years old and become tan.
If someone removes new restorated Da Vinci images from Old images , I think we can reach to nonlinear noise and grades of time effects.
That is the only way I could think but I dont know to separate new red color from old brown color on top of it. May be bw but I dont know ?
Umut