Changes the lighting direction between cold, dark night and warm, bright daylight. The strength you need will depend on the prompt, image, and video, so there isn't really a single "correct" setting.
The idea is not to use it as a simple "turn this into night" or "turn this into day" switch. It works best when your prompt already describes the scene you want, and the slider is then used to push the lighting a little more toward warm sunlight or cold nighttime darkness when the prompt alone isn't quite getting there.
For example, if your prompt describes a sunset but the result is still too dark and cold, increasing the strength can push it further toward warm daylight. Likewise, if you describe a nighttime scene but it still looks too bright, moving in the opposite direction can help push it toward colder, darker night lighting.
You can technically use the slider to force a scene from day to night or night to day, but that's not really what it was designed for. If you push it too far against what the prompt and scene describe, the result can become weird or unrealistic. Think of it more as a way to fine-tune the lighting direction rather than completely replacing the lighting described in your prompt.
The model is very capable and multimodal, so it can also make small contextual adjustments when the lighting changes. If something would logically look different under warm daylight versus cold nighttime lighting, the model may adapt those details to make the scene more coherent.
However, the prompt still takes priority. If you explicitly describe what you want, the model will follow your prompt. The slider is there to give you an extra bit of control when you want slightly more or slightly less of that day/night effect.
Technically, this was trained at rank 1 using only the last 5 layers. The goal was to keep the LoRA small, fast, and focused on the part of the model where this change matters most, instead of modifying a large portion of the model.
So the basic idea is:
Prompt = tells the model what scene and lighting you want.
DayNight Slider = lets you push that lighting a little more toward cold, dark night or warm, bright daylight.
The sweet spot will depend on the prompt and image. Start relatively low and increase it only as much as needed. If the result starts doing strange things, the strength is probably pushing harder than the scene needs.
