Nirmion
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Image Tools / Local studio

Image Shadows and Highlights Adjuster

Adjust low- and high-luminance ranges independently with smooth weighting, browser-local preview, preserved alpha, and separate export.

Runs locallyNo image upload to Nirmion

Step 1 / Source

Choose one image

JPEG · PNG · WebP · 20 MB

Drop your image here

Or browse for a JPEG, PNG, or WebP image that you own or are authorised to edit.

One file · up to 20 MB · maximum 50 megapixels

Step 2 / Output

Image Shadows and Highlights Adjuster controls

Adjust shadows and highlights from -100 to +100 independently; zero leaves that weighted tonal range unchanged. Processing stays in this browser tab.

Adjust shadows and highlights from -100 to +100 independently; zero leaves that weighted tonal range unchanged.
Create the shadows-and-highlights imageThe source is not overwritten. Export creates a separate shadows-and-highlights image.
Keep this page open until the download begins.
01No server upload

The selected image is decoded and re-encoded inside this browser tab.

02Working copy released

After download, the preview URL, decoded bitmap, canvas, and selected source reference are cleared.

03Your download remains

Nirmion cannot remove the finished file from your device or browser download history.

Workflow guide

Use image shadows and highlights adjuster with a reversible review path

Squared luminance weights apply the shadow control most strongly to dark pixels and the highlight control most strongly to bright pixels. Compare the derivative with the untouched source before using it downstream.
A

What you need

Choose one authorised JPEG, PNG, or WebP still image up to 20 MB and 12 million decoded pixels. Animated frames are not processed.

B

Social-ready choices

Lift detail in a dark diagram while reducing bright-paper glare, then inspect midtones for halos or flattened separation.

C

What you receive

Download a separate shadows-and-highlights image; the original file on your device remains unchanged.

Decision guide

What image shadows and highlights adjuster changes

Squared luminance weights apply the shadow control most strongly to dark pixels and the highlight control most strongly to bright pixels.

This global tonal weighting does not segment subjects, reconstruct clipped detail, perform local tone mapping, or replace raw development. Browser-local processing avoids a Nirmion file upload, but it cannot remove copies stored elsewhere.

MDN Canvas pixel manipulation

Useful checks for image shadows and highlights adjuster

  1. Lift detail in a dark diagram while reducing bright-paper glare, then inspect midtones for halos or flattened separation.
  2. Create a review derivative while retaining the original for correction, comparison, or a different export.
  3. Test the operation on representative shadows, midtones, highlights, edges, text, and transparent areas.

Good to know

Important image boundaries

Why might a PNG not become smaller?
PNG is lossless and browsers do not expose a quality control for it. Choose WebP or JPEG when reducing file size matters more than exact lossless pixels.
Are animated images supported?
No. The workspace accepts still JPEG, PNG, and WebP files. Re-encoding an animated source would otherwise keep only one frame.
What does clearing the file mean?
Because processing is local, there is no Nirmion server copy to delete. The tab releases its working references after success; your downloaded output remains on your device.

Questions answered

Frequently asked questions

Does Image Shadows and Highlights Adjuster upload my image?

No. For supported JPEG, PNG, and WebP inputs, decoding, pixel transformation, canvas rendering, and export run in your current browser tab. Nirmion does not send the selected image to its API for this workflow. The output is a new derivative, while the original file on your device remains unchanged and should be retained for comparison or later editing.

How does Image Shadows and Highlights Adjuster change pixels?

Squared luminance weights apply the shadow control most strongly to dark pixels and the highlight control most strongly to bright pixels. Existing alpha values are preserved. The operation does not infer subjects, recover clipped detail, calibrate a display, or develop raw camera data. Inspect fine edges, gradients, text, skin tones, and transparent pixels in the exported file before relying on the result.

What are the practical limits of Image Shadows and Highlights Adjuster?

This global tonal weighting does not segment subjects, reconstruct clipped detail, perform local tone mapping, or replace raw development. The workspace accepts one supported still image up to 20 MB and caps this pixel-intensive operation at 12 million decoded pixels for predictable browser memory use. Output depends on browser decoding and encoding support. Animation, raw development, ICC calibration, layer editing, and batch processing are outside this tool's verified scope.