如何為 Guava 撰寫提示詞

最重要的規則

1. 1

   描述整張照片,而不只是主體

   先說明這是哪種照片(雜誌人像、隨手拍的手機快照、攝影棚產品照),接著寫主體、地點、光線和鏡頭。光線和鏡頭正是讓照片看起來真實的關鍵。

2. 2

   人物要描述得精確

   寫出具體年齡(「四十出頭」,不要只寫「年輕」)、臉型與眼睛、膚色與膚質,以及每件衣物和它的布料。描述模糊的人物都會長成同一張臉。

3. 3

   要求真實的質感

   可見的毛孔、雀斑、細紋、翹起的髮絲、起皺的亞麻、磨損的皮革。「無瑕」、「完美肌膚」這類字眼會得到蠟像般、過度修飾的結果。

4. 4

   讓光線有來源和方向

   左側的柔和窗光、她身後的低角度太陽、頭頂一顆裸燈泡。光線的敘述要前後一致:「陰天卻有正午的強烈陰影」會讓模型混亂。

5. 5

   用 Guava 2 打草稿,用 Guava 2 Pro 完稿

   先在速度較快的 Guava 2 上調整好提示詞,再用同樣的文字在 Guava 2 Pro 上生成最終滿意的版本。

可以參考的提示詞

• 足以假亂真的人像

  Realistic editorial portrait photograph. A 41-year-old Nigerian woman with a heart-shaped face, high cheekbones, wide-set dark brown eyes and deep brown skin with visible pores and a few small moles along her jaw sits on a wooden stool, turned slightly to her left, looking straight into the lens with a calm, faintly amused expression. No makeup apart from a soft matte plum lipstick. Her natural hair is gathered into a high puff, a few loose coils catching the light. She wears a rust-colored linen shirt with the sleeves rolled to the elbow, the fabric creased at the shoulders, and thin gold hoop earrings. Her left forearm rests on her knee; her right hand holds a pair of reading glasses by one arm. Behind her, a plain plaster wall in warm gray. Soft window light from the front-left at about 45 degrees, a gentle shadow falling to the right. Shot on an 85mm lens at f/2.8, chest-up, eye level, shallow depth of field. Natural color, fine grain.

  為什麼有效: 它依照 Guava 最擅長解讀人物的順序來描述她(身分、臉、皮膚、服裝、姿勢、光線、鏡頭),並寫出真實的質感,而不是說「漂亮」或「無瑕」。

• 隨手拍的手機快照

  Candid smartphone photo, slightly tilted, taken across a crowded kitchen table during a family dinner. A grandfather in his late seventies with a white mustache and a checked flannel shirt laughs with his eyes squeezed shut, holding a forkful of noodles halfway to his mouth. Plates of dumplings, a half-empty bottle of orange soda and crumpled napkins crowd the table; a child's arm reaches in from the left edge. Warm overhead light from a single paper lamp, a little harsh, with mild noise in the shadows and a hint of motion blur on his hand. Wide-angle phone lens, everyday snapshot realism.

  為什麼有效: 真實的照片都有瑕疵:歪斜的構圖、被裁掉的手臂、刺眼的室內燈光和一點模糊,這些都在告訴 Guava 要生成快照,而不是攝影棚照片。

• 產品照

  Studio product photograph of a matte black ceramic pour-over coffee dripper resting on a slab of pale travertine, a thin coil of steam rising from it. A 100mm macro view from slightly above shows the fine speckled glaze, the spiral ridges inside the cone and a single drop of coffee hanging from the spout. A small glass carafe sits blurred behind it. One large softbox high on the left, a white reflector card on the right, deep soft shadows. Neutral warm-gray background, crisp detail, no noise. No writing, logos or labels anywhere in the image.

  為什麼有效: 材質、打光設定和鏡頭都有明確寫出,最後一句則避免 Guava 在產品上自行編造品牌。

• 你的 Character 換上新裝、來到新地點

  @mara sits at a window table in a small Lisbon café, keeping her face, skin tone and shoulder-length auburn hair exactly as in her image. She wears a camel wool blazer over a cream silk blouse and holds a white espresso cup in her right hand, glancing out of the window. Soft overcast daylight from the window on the left, a wall of blue and white tiles behind her, shallow depth of field. Candid editorial photograph, 50mm lens at eye level.

  為什麼有效: handle 帶入臉部特徵,第一句說明哪些保持不變,其餘只更改服裝和場景。請把 @mara 換成你自己的 Character。

• 招牌清晰可讀的街拍照

  Realistic photograph of a narrow side street in Porto after rain. Above a small bakery hangs a hand-painted wooden sign reading "PADARIA LUZ" in cream serif capitals on a faded green board, and a chalkboard by the door says "Bolo de arroz 1,50 €" in white handwriting. Wet cobblestones reflect the warm shop window; a man in a dark raincoat walks past, slightly blurred. 35mm lens at eye level, soft overcast light.

  為什麼有效: 每段文字都會連同載體、顏色和位置逐字引用，Guava 就能把文字畫在正確的表面上。