Add a Rainbow

ROLE: You are an expert landscape photographer and senior digital matte painter. Your task is to modify the uploaded source image by adding a photorealistic rainbow of type [rainbow_type] into the sky or background. Treat the foreground subjects, terrain, and architecture as ground truth, ensuring the rainbow integrates naturally behind them.

EDIT: Render a realistic, semi-transparent rainbow arc in the background sky. The rainbow must conform to the stylistic choice of [rainbow_type]. It must follow correct atmospheric physics, featuring a natural spectral band transition (red on the outer edge, violet on the inner edge) and blending seamlessly with the clouds, mist, and lighting of the original scene.

PRIMARY OBJECTIVE: Add a convincing, beautiful rainbow that looks as if it was captured in-camera during the original landscape or portrait shot. The rainbow must respect depth of field, atmospheric haze, and foreground occlusion, appearing physically integrated into the background.

EDITING PRIORITY:
1. Render the rainbow according to the selected [rainbow_type].
2. Ensure the rainbow is placed behind all foreground elements (trees, buildings, people, mountains) to maintain correct spatial depth.
3. Blend the rainbow's colors semi-transparently with the sky, clouds, and background atmospheric haze.
4. Match the soft lighting, color temperature, and contrast of the original photo.
5. Keep all foreground elements, textures, and details completely untouched.

BACKGROUND & EDGE INTEGRITY:
- The rainbow must not overlap foreground objects; it must be perfectly occluded by edges of buildings, foliage, mountains, or subjects in the mid-ground.
- Ensure the edges of the rainbow are soft and diffuse, matching the moisture and mist level of the air in the photo.
- If the background sky has clouds, the rainbow should weave naturally through them, showing brighter where the air is mistier and fading where the sky is clear, according to meteorological physics.
- Maintain the camera's original focus. If the background sky is softly blurred, the rainbow must have matching soft focus.

STRICT PRESERVATION RULES:
- Do not alter the original crop, perspective, camera angle, or aspect ratio.
- Do not change the colors, lighting, or details of the foreground subjects, ground, or structures.
- Do not add artificial rain, storm clouds, or weather effects unless they are part of the original image or naturally required to blend the rainbow.
- Keep the original image sharpness and film grain intact.

REALISM & INTEGRATION:
- The colors of the rainbow must follow the natural light spectrum: Red, Orange, Yellow, Green, Blue, Indigo, Violet. The transition between colors must be smooth and continuous, not solid blocks.
- The rainbow must be semi-transparent, allowing background clouds and blue sky to show through its colors.
- Adjust the overall brightness of the rainbow to match the time of day. A rainbow during sunset should have warmer, red-dominant tones, while a midday rainbow should have clean, bright spectral colors.
- Ensure that any ambient light cast from the rainbow onto the atmosphere is extremely subtle and physically plausible.

ARTIFACT PREVENTION:
- Avoid sharp, hard-edged vector lines that look pasted on.
- Prevent the rainbow from appearing on top of foreground trees, power lines, or hair strands.
- Avoid neon, glowing, or cartoonish color palettes that break photographic realism.
- Do not allow the rainbow to look perfectly uniform if the background sky has varying cloud densities.

QUALITY CONTROL:
- Examine the boundaries where the rainbow meets foreground objects at 100% zoom to verify clean occlusion masks.
- Confirm that the rainbow's curve is a perfect, natural geometric arc.
- Verify that the transparency looks natural against the background clouds.

OUTPUT: Deliver a single, high-resolution final image with the integrated rainbow, matching the exact dimensions and photographic quality of the original upload. No text, watermark, or side-by-side comparison.