The influence of lighting on the transparency of tulle

In Planoplan, the transparency of sheer curtains in renders depends on the lighting setup of the scene. When creating visualizations, the app uses automatic exposure — it automatically adjusts the frame brightness so that the image looks balanced, without being overexposed or too dark.

Two main factors affect the final transparency of sheer curtains:

• the balance between external and internal lighting;
• the color and brightness of the room finishes.

How lighting affects curtain transparency

Let’s look at several examples using the same scene — a window with sheer curtains.
On the left is a single-layer curtain (one surface), and on the right — a double-layer curtain (two surfaces placed one behind another).

Lighting preset “Noon” (Sunlight 0.25, Sky light 0.25)

Direct sunlight hits the curtain. There are no indoor light sources — lighting comes only from outside.

Render 1: the curtain occupies most of the frame. The overall brightness is determined by the curtain, so a single layer looks transparent, while a double layer appears noticeably less transparent.

Render 2: the camera angle is wider, capturing more of the room. Because of this, the curtain appears brighter, and the view outside the window becomes less visible.

Render 3: the same scene, but with darker wall finishes. In this case, the bright spot on the curtain becomes even more intense, and transparency visually decreases.

Render 4–5: different camera angles with the same settings show similar behavior.

Lighting “Noon” without direct sunlight

Sunlight is turned off, leaving only the sky light. The image becomes less contrasty, and the curtain looks evenly lit but less transparent.

Dominant indoor lighting

Settings: Sunlight 0.01, Sky light 0.01, and a yellow lamp turned on inside the room, much brighter than the outdoor light.
In this case, the curtain becomes maximally transparent because the indoor light is stronger than the light coming from outside.

Conclusion

The transparency of sheer curtains directly depends on the balance between indoor and outdoor lighting.
By adjusting the intensity of the light sources, you can control how transparent the curtain will appear in the final render.