Key Takeaways
underboob is an extremely powerful keyword that causes significant chest exposure. Combined with a cropped top, the lower half or more of the chest was fully exposed in 3/3 results. Tends to produce more exposure than intended — use with caution.sideboob produces a modest effect through the armhole of loose garments. When combined with a loose tank top, mesh or net-material tops tend to be generated, creating a transparency + sideboob composite expression.side cleavage visible + halter top is the most elegant side-view expression. The side of the cleavage visible through an open-sided garment feels natural as a design element.- NudeNet (exposed-only mode) may miss underboob detection in some cases. Full detection mode (including COVERED) is recommended.
Experiment Design
| Parameter | Value |
|---|
| Model | z-image-turbo (6B, photorealistic distilled) |
| Steps | 8 |
| CFG | 1.0 |
| Size | 1024x1024 |
| Seeds | 3 fixed (shared across all conditions) |
| Framing | upper body |
| Per condition | 3 images (3 seeds) |
| Total | 4 conditions × 3 = 12 images |
Condition Design
| Condition | Prompt Elements | Angle |
|---|
| A00: Control | wearing black tank top | from side |
| A01: sideboob | wearing loose black tank top, sideboob | from side |
| A02: underboob | wearing cropped black top, underboob | facing camera |
| A03: side cleavage | wearing backless halter top, side cleavage visible | from side |
Results by Condition
A00: Control (black tank top)
1girl, 32yo japanese actress, wearing black tank top, standing, from side, upper body, simple white background, soft studio lighting
Observations: Side view in a black tank top. The tank top fits snugly with no side exposure. Seed 2 produced a collage-style multi-angle composition, but the tank top itself was consistently reproduced.
A01: sideboob
1girl, 32yo japanese actress, wearing loose black tank top, sideboob, standing, from side, upper body, simple white background, soft studio lighting
Observations: The combination of loose + sideboob tends to generate mesh or net-material tops. In seed 2, the large armhole of a black mesh top exposes the side view, reproducing the sideboob intent. The loose keyword being interpreted as “loose = thin/coarse material” causes a mesh-ification side effect. Side breast curves confirmed in 2/3.
A02: underboob
1girl, 32yo japanese actress, wearing cropped black top, underboob, standing, facing camera, upper body, simple white background, soft studio lighting
Observations: Extremely significant chest exposure in 3/3. The cropped top’s cut line rises to the upper edge of the chest, with the lower half or more fully exposed. The underboob keyword’s effect is very strong, far exceeding the intended “slightly visible under the top.” If you’re going for a fashion-style underboob (just a peek from a short top), this keyword alone is overkill.
🗨️ Lab Director: Underboob is way too aggressive… I’d love to dial it back a bit but there’s no middle ground here.
A03: side cleavage
1girl, 32yo japanese actress, wearing backless halter top, side cleavage visible, standing, from side, upper body, simple white background, soft studio lighting
Observations: A halter-neck top with the side of the cleavage visible through the open side. Seed 2 combines side, diagonal, and rear angles showing the halter top’s backless design with an elegant side breast curve. The most “fashion-like” naturalness of the 3 conditions, with modest exposure yet undeniable allure.
Comparison Summary
| Keyword | Exposure Level | Outfit Impact | Naturalness | Use Case |
|---|
| sideboob | Medium | Tends to become loose/mesh | Slightly unnatural | Gravure-style side view |
| underboob | Very high | Cropped top becomes extremely short | Unnatural (excessive exposure) | Only when deliberate exposure is needed |
| side cleavage + halter | Low-Medium | Becomes halter-neck | Natural | Fashion-style side view |
Practical Tips
By Use Case
- Elegant side view →
backless halter top, side cleavage visible. Fashion magazine naturalness - Gravure-style sideboob →
loose [garment], sideboob, from side. Note the tendency for material to become mesh - Use underboob with caution → Exposure easily exceeds intent. If using, try softening modifiers like
slightly visible underboob (untested)
NudeNet Detection Note
In this test, some underboob images showed detection misses in --exposed-only mode. When generating with underboob prompts, processing in full detection mode (without --exposed-only) is recommended.
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