How to Fix Blown-Out Highlights in AI-Generated Images

How to Fix Blown-Out Highlights in AI-Generated Images

Blown-out highlights are regions of an image where brightness has been pushed to pure white with no tonal information remaining. In AI-generated images, this happens most often in sky regions, bright light sources, reflective surfaces, and any area the model renders as very brightly lit. The problem is visually obvious and degrades image quality significantly, particularly for wallpaper use where the overexposed areas create flat, lifeless zones in an otherwise detailed image.

The fix depends on whether the highlight data is recoverable (the image file contains sub-surface tonal information that appears white but is not truly clipped) or whether it is genuinely gone. This article covers both cases and the prevention approach in prompting.

Understanding the Difference: Recoverable vs Genuinely Clipped

JPEG and PNG images use 8-bit per channel encoding, which means tonal values range from 0 (black) to 255 (white) per channel. When all three color channels (red, green, blue) reach 255 simultaneously, the area is truly clipped to white. There is mathematically zero recoverable detail because no tonal information was encoded.

However, many areas that appear white in a JPEG are not fully clipped. They are very bright but still have some encoded tonal information across channels, particularly if the original AI output was generated at higher quality settings. These areas look white on screen at standard exposure but can be pulled back with highlight recovery tools to reveal detail that was there all along.

How to check if highlights are recoverable

In Lightroom: pull the Highlights slider all the way to -100. If any detail appears in the previously white area, the highlights are at least partially recoverable. If the area remains pure white with no change, the highlights are genuinely clipped in the JPEG.

In Photoshop: use Levels and look at the individual channel histograms. If red, green, and blue channels all stack against the right wall simultaneously, the area is clipped. If only one or two channels are fully clipped while others have room, partial channel recovery may be possible.

Method 1: Lightroom Highlight Recovery

Lightroom's Highlights and Whites sliders recover encoded highlight detail. This is the fastest first-pass method.

Basic recovery workflow

1. Import the image into Lightroom.
2. Pull the Highlights slider to -100 first. Watch the sky or overexposed area for emerging detail.
3. Pull the Whites slider toward -50 to -80. This pulls the absolute ceiling of the tonal range down and reveals previously clipped areas.
4. If detail appears but looks flat and grey, add a small amount back to Clarity (+10 to +20) in the recovered area using a masked adjustment brush to restore micro-contrast in the recovered tones.
5. Balance the overall exposure: reducing highlights and whites typically makes the midtones feel slightly darker. Add back +10 to +20 Exposure and compensate with +15 to +30 Shadows if needed.

Targeted highlight recovery with masks

If only one region of the image is blown out (a sky, a bright window, a light source), use Lightroom's luminance range mask to apply recovery only to the brightest tones without affecting the well-exposed areas.

1. Create a new Masking layer (Mask > Luminance Range).
2. Set the range to select only the brightest tones (upper 20-30% of the luminance range).
3. Apply Highlights -80 and Whites -60 only to the masked bright area.
4. The rest of the image is unaffected.

Method 2: Photoshop Luminosity Blend

When Lightroom recovery is insufficient, Photoshop's luminosity blending technique can recover more detail from areas where individual color channels are not fully clipped even though the combined RGB appears blown.

Channel recovery workflow

1. Open the image in Photoshop.
2. Go to the Channels panel and click through each channel (Red, Green, Blue) individually.
3. Find the channel with the most retained detail in the blown area. Often the blue channel retains sky detail even when the image looks white.
4. Duplicate that channel to a new layer.
5. Convert it to a luminosity mask by Ctrl/Cmd+clicking the channel thumbnail to load it as a selection, then invert the selection.
6. Use Curves to darken the blown area using the channel data as the guide for where detail still exists.

This technique requires more steps but can recover detail in images where Lightroom's approach shows no improvement.