Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, [胸の言葉]
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, flat chest
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, small bust
flat chest より少しふくらみがあり、控えめな大きさです。A cup と書いた4枚も、ほぼ同じ大きさでした（裏側で書いています）。
直して効いたComfyUI・ベースに足した言葉：busty glamour model with a very large full bust that strains the fitted tank top
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, busty glamour model with a very large full bust that strains the fitted tank top
4枚とも、ベースや large bust の4枚よりはっきり大きな胸になり、タンクトップの胸元が押し上げられています。large bust・huge breasts のような大きさの言葉は効かず、「グラビアモデル」「服が張る」と、見た目と服の様子で書いたら効きました。3枚目だけ、頼んでいない前開きのファスナーがタンクトップに付いています。
服で見え方を比べる：ゆったりしたTシャツ・シャツ・ワンピース
同じ大きな胸でも、服によって見え方と、通るツールが変わりました。ゆったりした T シャツは ChatGPT が通し、シャツとワンピースは ChatGPT に止められたので ComfyUI で作っています。
loose oversized t-shirtゆったりしたTシャツ
効かなかったChatGPT・ベースに足した言葉：large bust（服はゆったりした T シャツ）
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a loose oversized white cotton t-shirt, large bust
ChatGPT は、ゆったりした T シャツなら large bust も4枚とも通しました。ただ、T シャツが胸から下へまっすぐ落ちて、大きさはほとんど分かりません。服がゆったりしていると、胸の言葉は服に隠れてしまうようです。
直して効いたChatGPT・ベースに足した言葉：busty glamour model with a very large full bust that fills out the loose t-shirt
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a loose oversized white cotton t-shirt, busty glamour model with a very large full bust that fills out the loose t-shirt
そこで、ComfyUI で効いた「服が張るほど」の書き方を、T シャツ用に「ゆったりした T シャツをふくらませるほどの大きな胸」と言い換えました。ChatGPT はこれも4枚とも通し、2〜4枚目は T シャツの胸元がはっきり持ち上がっています。1枚目だけ、ふくらみが控えめです。体に沿うタンクトップでは止められた大きい胸も、ゆったりした服なら ChatGPT で作れました。
button-up shirtシャツ
直して効いたComfyUI・ベースに足した言葉：busty glamour model with a very large full bust that strains the shirt buttons
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a white button-up shirt tucked into high-waisted trousers, busty glamour model with a very large full bust that strains the shirt buttons
4枚とも大きな胸になりました。ただ、「ボタンが張る」と書いたせいか、2〜4枚目はボタンが外れて胸元が大きく開いています。ボタンを留めたまま大きく見せたいときは、strains the shirt buttons を外して、fills out the shirt のように書くほうがよさそうです（この記事では試していません）。
knit dressニットのワンピース
直して効いたComfyUI・ベースに足した言葉：busty glamour model with a very large full bust that strains the fitted dress
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted black knit midi dress, busty glamour model with a very large full bust that strains the fitted dress
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, large breasts
bust を breasts に替えただけでは、ほぼ変わりません。
効かなかったComfyUI・ベースに足した言葉：huge breasts
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, huge breasts
「巨大な」と強くしても、ふつうの大きさのまま。むしろ large breasts より控えめな4枚もあります。
効かなかったComfyUI・ベースに足した言葉：voluptuous curvy hourglass figure with a big bust
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, voluptuous curvy hourglass figure with a big bust
効かなかったComfyUI・ベースに足した言葉：petite slender boyish figure with a completely flat chest
この4枚のプロンプト
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, petite slender boyish figure with a completely flat chest
Photorealistic waist-up photograph of a beautiful 20-year-old Japanese woman, sophisticated grown-up look, elegant mature face with a defined jawline and high cheekbones, long glossy black hair parted in the center with soft waves, defined winged eyeliner, glossy nude lips, standing facing the camera with her arms relaxed at her sides, in a bright photo studio with a plain light gray background, soft daylight, shot on a 50mm lens, wearing a fitted white ribbed knit tank top, A cup bust
ChatGPT は A cup bust も通しました。ただ、4枚は small bust とほぼ同じ大きさで、2枚目と3枚目はふつうに近い大きさです。カップの記号で大きさを細かく指定するのは、ChatGPT でもむずかしいみたいですね。
よくある質問
ChatGPTで大きい胸は作れませんか？
ゆったりした T シャツなら作れました。「ゆったりした T シャツをふくらませるほどの大きな胸」と書くと4枚とも通り、2〜4枚目ははっきり大きな胸です。タンクトップ・シャツ・ワンピースのような体に沿う服では、medium bust より大きい言葉は止められています。
カップ数（A〜G）は効きますか？
ChatGPT では A cup だけが通り、small bust とほぼ同じ大きさでした。C・E・G は止められ、ComfyUI では3つともほぼ同じ大きさです。カップの記号より、small bust や「服が張るほど」のように、見た目で書くほうが寄りました。
StableDiffusionのほかのモデルでも同じですか？
この記事で試したのは、ChatGPT と、ComfyUI の HARUKI_MIX ZIT2606Real だけです。胸の言葉の効き方はモデルによって違うので、別のモデルでは large bust がそのまま効く場合もあると思います。モデルの選び方は、ComfyUI の記事にまとめました。
出したい胸から選ぶプロンプト
出したい胸
ツール
ベースに足す言葉
平らな胸
ChatGPT
flat chest
小さめの胸
ChatGPT
small bust（A cup bust もほぼ同じ）
大きな胸
ComfyUI
busty glamour model with a very large full bust that strains the fitted tank top
ゆったりした服の大きな胸
ChatGPT
wearing a loose oversized white cotton t-shirt, busty glamour model with a very large full bust that fills out the loose t-shirt
体に沿うワンピースの大きな胸
ComfyUI
wearing a fitted black knit midi dress, busty glamour model with a very large full bust that strains the fitted dress
