AI 이미지 전반의 문자 일관성

Prompts alone fail because every generation starts from fresh random noise, and a description like "a woman with short red hair and a green jacket" fits millions of different faces. Even with a fixed seed, changing the prompt changes the denoising path, so the face changes too. Practitioners use three main families of techniques. Reference-image conditioning passes one or more images of the character through an image encoder and injects the resulting features alongside the text. IP-Adapter (Tencent, 2023) is a widely used open example, and Midjourney added a character reference parameter in 2024. It needs no training and captures the overall look well. Fine details such as tattoos, jewelry and printed patterns tend to drift, though, and a high reference weight can also copy the reference's pose and lighting. Character LoRAs, and the related DreamBooth method, fine-tune the model on a set of images of the character (often 10 to 30 or more) and tie the result to a rare trigger token. This is usually the most faithful option for complex designs, including outfits and non-human characters. The costs are training time and two failure modes. An overfit LoRA repeats the poses, expressions or backgrounds from its training set. An underfit one loses the identity. Using two character LoRAs in one image often blends their features. Identity encoders such as InstantID, PhotoMaker and IP-Adapter FaceID extract face-recognition-style embeddings from a single photo. They preserve facial identity strongly, but only the face: hair, clothing and body shape are not locked. They also struggle with stylized or cartoon characters, because the face recognizers behind them were trained on real photographs. Newer multimodal image models can take images as context and follow edit instructions like "same character, now sitting." A common misconception is that any one method solves consistency. In practice, scenes with several characters still bleed attributes between them, and most professional workflows combine methods and then fix remaining drift by hand.