Preheat the oven to Gas Mark 4, 180°C (350°F). Wash and dry the potatoes. Peel the potatoes and cut them into very thin slices using a mandolin. Place the potato slices in a large salad bowl filled with water at room temperature for 15 minutes. Drain the potato slices well and dry them with paper towels. Place the potato slices in a salad bowl, drizzle with oil and add the paprika and salt. Stir gently to coat without breaking the potato slices. Place a sheet of baking paper on a baking tray. Spread the potato slices, taking care to keep them well separated from each other. Bake for about 15 minutes, the crisps should appear crispy as desired.