The problem: Face, outfit, and DNA drift between frames — the lead looks like a different person every shot.
Tools: Gemini Nano Banana + JSON character sheet
Workflow steps
- Open Gemini and select Nano Banana (image model).
- Upload 3-5 reference photos of your character (front, side, full body).
- Paste the locked JSON character sheet below — every scene must reference this exact block.
- For each new scene, prepend the JSON, then describe the action only. Never re-describe the character.
- If drift happens, regenerate with reference image re-uploaded — never edit text-only.
Ready-to-copy prompt
{
"character_dna": {
"name": "Arjun",
"age": 28,
"ethnicity": "North Indian, Punjabi heritage",
"skin_undertone": "warm wheatish, subtle olive base",
"face": {
"shape": "oval, defined jawline",
"eyes": "deep brown, almond-shaped, thick lashes",
"eyebrows": "thick, naturally arched",
"nose": "straight bridge, medium width",
"lips": "medium fullness, neutral rose",
"facial_hair": "trimmed 5-day stubble"
},
"hair": "jet black, side-swept undercut, slight texture",
"build": "6'0\", lean athletic, 78kg",
"wardrobe_locked": "charcoal merino turtleneck, black tailored trousers, vintage Rolex Submariner"
},
"render_lock": "match these features in every frame, do not stylize or anime-fy",
"negative_prompt": "no plastic skin, no Western features, no outfit changes, no age drift, no clone face"
}
Save this JSON as a Google Doc and paste it as the FIRST block of every single prompt across your film. Character drift drops by 80%.