Wash and core the apples then slice into ΒΌ inch rings. A Mandolin can make this process a lot easier.
Toss out the top and bottom rings.
Put the lemon juice and water into a medium sized bowl.
Bathe the apple rings in the lemon water, do them in batches if they all won't fit.
Dry the apples on a clean kitchen towel then lay slices on wire racks over baking sheets.
Bake the apple rings in the oven for 2-10 hours on low heat (140 degrees F), turning occasionally. Dry longer for crisp slices, and less for soft slices.
Remove the slices from the oven and allow to cool completely before storing in sterilized airtight jars in a dark cool place.