Mix the water, gelatin, and chlorella in a pot.
Heat until the mixture starts to thicken and bubble.
Pour into the mold and let dry. The drying period strongly depends on the thickness of the final product but also on room temperature and humidity. It may take up to several days until sheet is fully dry.
Once the sheet is fully dry it can be removed from the mold carefully using a scalpel or thin knife. Note that the ochre collects at the bottom of the sheet, creating leather-like material that is harder and denser at the bottom.