A clear spill on a white glossy plate is hard to show because viewers see shape mostly through highlights and shadows; if the lighting is very soft and shadowless, the liquid has almost no visible edge.

What helps most is creating controlled reflections:

• Use a relatively harder light at a low/raking angle so the spill catches a highlight.
• Adjust camera and light position until the liquid reflects light differently from the plate.
• If needed, shape the light with flags/masks so the reflection falls mainly on the spill, not the whole plate.
• Polarizers may help control reflections, but this can take careful adjustment.

The tradeoff is that stronger directional light will also add shadows elsewhere, so you’ll need to balance visibility of the spill against the look of the rest of the food.

If the spill still won’t read clearly, a composition change may work better than lighting alone—for example, showing the essence in a small glass container nearby to give viewers context that a clear liquid is present.