How to use
- On the HDR tab, upload at least two photos of the same scene taken at different exposures and set the EV value for each one.
- Click the merge button, then adjust tone mapper, exposure, saturation, gamma and bloom while watching the preview and histogram.
- Download the result as a PNG. On the Spectral tab, upload one photo and move the temperature, tint, intensity and CRI sliders.
The HDR tab combines photos of the same scene shot at different exposures. Each image has an EV field you can raise or lower in steps of one, from -10 to +10. Uploads start at -2, 0, +2 and so on, so correct them to match how you shot the set. The tool needs at least two images, and three are recommended. The merge weights each pixel by how well exposed it is, favoring mid-tones over clipped shadows and highlights, and it assumes a simple gamma of 2.2 rather than a measured camera response curve.
After merging, you tone-map the result back to a normal image. You can choose ACES or Reinhard. Sliders set exposure from -4 to +4 stops, saturation from 0 to 2, gamma from 1 to 3, bloom amount from 0 to 1 and bloom threshold from 0 to 1. A luminance histogram shows how the tones are spread. Previews use a copy scaled to 800 pixels wide for speed, while the download is processed at the full merged size and saved as a PNG. The photos are not aligned automatically, so use a tripod or well-aligned shots of equal size.
The Spectral tab is a simple relighting tool for one photo. Temperature runs from 1500 K to 12000 K, tint from -100 to 100, intensity from 0.1 to 3 and a CRI slider from 0 to 2 that acts as a saturation control. It multiplies the color channels by a light color derived from the temperature, so it behaves like a color cast, not a physical simulation of light. A divider lets you compare the original with the result, and the download is a JPEG.
Both tabs run in your browser, and your photos are not uploaded.
FAQ
How many photos do I need for HDR?
At least two. Three or more are recommended, taken at different exposures.
Are the photos aligned automatically?
No. Shoot from a stable position so the frames line up, and use images of the same size.
What do the EV numbers mean?
They are the exposure offset of each photo in stops, relative to the others. Set them to match how you shot the bracket.
What does the Spectral tab really do?
It tints the photo using a light color calculated from a color temperature, plus tint, intensity and saturation controls.
Are my photos uploaded?
No. Merging and relighting are done in your browser.