12 Details That Make AI Cast Photos Look Fake (and How to Fix Them)
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You can usually tell a generated cast photo in under a second, and it is almost never the big things that give it away. It is the edges, the shadows and the joints. Here are the twelve failures that come up again and again, and how to fix each one.
Why cast photos are unusually hard to fake
A cast is a rigid object wrapped around a soft, moving body. That means every convincing cast photo has to get three separate things right at once: the surface of the material, the way it interfaces with skin, and the way the body compensates for being unable to bend. General purpose image tools handle the first reasonably well and the other two badly, which is why so many results look like white paint rather than plaster.
Once you know what to look for, you can either fix your prompts or pick a tool that already handles it. Let us go through the list.
The twelve giveaways
1. Pure white plaster
Real plaster is off-white, faintly grey, and picks up colour from whatever is around it. Pure RGB white is the single most common tell. Ask for aged or slightly discoloured plaster, and avoid words like bright or pristine.
2. Sharp, unfinished edges
Every real cast edge is trimmed and then covered with the stockinette lining folded back over it, creating a soft rolled lip. A cast that ends in a clean cut line against skin is the fastest way to lose a knowledgeable viewer. Always name the padded edge explicitly.
3. No compression at the skin line
Where a rigid shell meets soft tissue, the tissue bulges slightly on both sides of the edge. Without that small deformation, the cast appears to hover a millimetre above the leg. This is subtle and enormously important.
4. Impossible joints
If a cast crosses a joint, that joint does not bend. A long leg cast with a visibly flexed knee, or an arm cast with a bending elbow, is an instant failure. Check every joint inside the plaster before you accept an image.
5. Wrong toe or finger exposure
A leg cast normally leaves the toes visible, with the plaster extending slightly further along the sole than over the top of the foot. An arm cast stops at the knuckles on the back of the hand and is cut back much further on the palm. Getting these lengths equal produces a mitten effect.
6. Missing lining
There is always a layer between plaster and skin: stockinette, then cotton padding. You should be able to see a hint of it at every opening. Bare skin butting directly against plaster looks like a costume.
7. No shadow underneath
A cast is a substantial object and it casts a real shadow onto the sheet, the chair or the other leg. Generated images frequently light the cast as if it were floating in a void. Ask for directional light and a visible contact shadow.
8. Uniform texture
Plaster bandage is applied in overlapping spiral layers, so the surface has a faint diagonal banding and slightly thicker ridges where the layers overlap. A perfectly smooth tube is a moulded prop, not a cast. Fiberglass shows a woven weave instead, as we explain in plaster versus fiberglass in photos.
9. Suspicious cleanliness
Casts get dirty. The heel goes grey, the palm edge picks up grime, and after two weeks there are usually signatures on it. Wear tells the viewer the cast has a history. Ask for a worn cast about three weeks old.
10. Normal posture
This is the biggest one, and it has nothing to do with the cast itself. Someone in a long leg cast stands with their weight on the other leg, hip dropped, shoulders counter-rotated, usually with a crutch. Someone standing squarely on both legs with a full leg cast is not believable no matter how good the plaster looks. Our guide to walking with a long leg cast covers what real posture looks like.
11. Crutches that do not fit
Crutch height should put the handgrip at wrist level with the elbow slightly bent, and the cuffs of forearm crutches sit a couple of inches below the elbow. Generated crutches are frequently far too short, held at the wrong angle, or not actually bearing any weight. We went through this in detail in cast photos with crutches.
12. No reason for the cast
The best cast photos imply a story. A hospital wristband, a discharge letter on the table, a bag of medication, a coat still on, a taxi outside. Without any context the image reads as a portrait of a cast rather than a photograph of a person who has one.
How to fix all twelve at once
You can address most of these through very specific prompting, and our guide to writing the perfect prompt for realistic cast photos gives you the phrasing. But there is a limit to how far prompting takes you with a general purpose tool, because the underlying model simply has no concept of stockinette or of a trimmed cast edge.
That is the gap Castlife Studio exists to close. It is trained specifically on cast imagery, so the edge treatment, padding, toe exposure and joint geometry are handled by default rather than requested. You upload a photo of yourself, choose the cast type, material and colour, pick a scene, and keep your own face and body in the result. There is a free preview tier so you can judge the realism before paying anything, and the pricing page shows what an HD, watermark-free download costs. We also compared it head to head against the mainstream tools in Gemini versus GPT versus Castlife Studio.
A quick checklist before you share
- Is the plaster off-white rather than pure white?
- Can you see a rolled, padded edge at every opening?
- Does the skin bulge very slightly where the cast meets it?
- Are all enclosed joints genuinely straight?
- Are the toes or fingers exposed correctly?
- Is there a contact shadow under the cast?
- Does the surface show layered banding or weave?
- Does the cast look a few weeks old?
- Is the weight clearly on the other leg?
- Are the crutches the right height and actually loaded?
- Is there something in the frame that explains the situation?
- Would you believe this photo if a stranger posted it?
If you can answer yes to all twelve, you have a photo, not a render.
Frequently asked questions
Which mistake matters most?
Posture. A viewer will forgive imperfect plaster texture but never a body that moves as if the cast were not there.
Can general AI tools produce realistic casts at all?
They can get close on simple short arm casts, and they struggle badly with long leg casts, spicas and anything involving crutches. The failure is usually edges and joint geometry rather than overall shape.
Should I add signatures?
Yes, for anything meant to look more than a week old. Signatures and doodles are one of the strongest realism cues available, and they cost you nothing.
How do I judge my own results objectively?
Crop tightly to the edge where cast meets skin and look only at that. If the crop is convincing on its own, the full image usually is too. If it is not, no amount of scene dressing will save it.
Put it into practice
Pick one of your existing cast photos and run it through the twelve-point checklist. Whatever fails, generate a new version and fix just that one thing. You can test as many variations as you like with the free preview in Castlife Studio, and our seven tips for photorealistic results is the natural next read.