Add the sugar and water in the pot and simmer until the syrup sets (7-8 minutes). Let it cool down and reach room temperature.
Add the blood orange juice.
If you are using gelatin granules, dissolve in a couple of spoonfulls of cold water; if you are using the leaves soak in cold water for 10 minutes and remove squeezing out most of the moisture. (check package instructions as well).
Once gelatin of choice is ready add to the syrup juice mixture.
Add Campari, stir and place in a glass or wherever you want to serve it in. Leave in the fridge to set, it normally takes about 5-6 hours, even better if you leave it overnight. Great to accompany with fresh fruit.