My way of painting older-looking parchment purity seals with crimson wax.

Parchment

1. Basecoat with Arabic Shadow . This might need two coats.
2. Layer with Zandri Dust
3. Layer with a 1:1 mixture of Zandri Dust and Ushabti Bone
4. Layer with Ushabti Bone
5. Add a wash of Seraphim Sepia diluted about 1:1 with Lahmian Medium
6. Add a recess shade and emphasise the shadows with Burnt Umber At this point you can add tiny lines to represent writing on the parchment with the same ink

Wax Seals

1. Basecoat with Bloodfest Crimson
2. Highlight with Wazdakka Red
3. Add spots of light with a 1:1 mixture of Wazdakka Red and Ungor Flesh