diff --git a/docs/PRODUCT.md b/docs/PRODUCT.md
index 9143152..0f652b7 100644
--- a/docs/PRODUCT.md
+++ b/docs/PRODUCT.md
@@ -4,6 +4,8 @@ SlabUploader creates one WooCommerce listing per wood slab for Whidbey Wood Stor
 
 Each slab is one unit and one listing. Photos and metadata are the inventory record.
 
+Photographs are taken of the slab on a green or black sheet. That is the capture starting state.
+
 ## Complete listing
 
 - Inventory photo(s), uniform 3:4 transparent PNG