Baking sheets (2) or fruit leather dehydrator trays (3)
Parchment paper or silicone baking mat
Method
Puree peaches in blender until smooth.
Place peaches in pot with half the sugar and juice of two limes. Heat on medium until puree has thickened slightly, about 10 minutes
Meanwhile, puree the blackberries (no need to rinse the blender from the peaches). Pass puree through a fine-mesh sieve to remove any seeds if desired.
In a small pot, add blackberries, remaining sugar and lime juice. Heat on medium until puree is slightly thickened, about 5 minutes.
On the fruit leather trays of your dehydrator, or a baking sheet fitted with parchment or a silicone mat, pour the peach puree into an even layer.
Spoon the blackberry puree into the peach puree. Then smooth the whole thing over to create an even layer of puree.
Dehydrate at 140 degrees for up to 8 hours, checking occasionally. Remove when fruit leather is still a bit tacky to cool.
Peel off fruit tray (in one piece, if you can!). Slice in strips and roll up.