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.
Image Tools / Local studio
Count visible decoded pixels near luminance endpoints and report shadow, highlight, and usable-range percentages without editing.
Step 1 / Source
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 megapixelsStep 2 / Output
This workflow uses one fixed, documented method so repeated runs on the same decoded pixels are comparable. Processing stays in this browser tab.
The selected image is decoded and re-encoded inside this browser tab.
After download, the preview URL, decoded bitmap, canvas, and selected source reference are cleared.
Nirmion cannot remove the finished file from your device or browser download history.
Workflow guide
Choose one authorised JPEG, PNG, or WebP still image up to 20 MB and 12 million decoded pixels. Animated frames are not processed.
Screen an exported diagram for crushed dark labels or blown pale detail before visual inspection on its intended background.
Review and download a separate luminance-clipping JSON report; the original file on your device remains unchanged.
Decision guide
Visible pixels at luminance 5 or below count as shadows, values at 250 or above count as highlights, and the remainder forms the usable range.
Endpoint counts are descriptive thresholds, not exposure diagnosis, HDR analysis, recovered detail, print proofing, or a quality pass/fail decision. Browser-local processing avoids a Nirmion file upload, but it cannot remove copies stored elsewhere.
MDN Canvas pixel manipulationGood to know
Questions answered
No. For supported JPEG, PNG, and WebP inputs, decoding, pixel inspection, transformation, and export run in your current browser tab. Nirmion does not send the selected image to its API for this workflow. The result is a separate derivative or report, while the original file on your device remains unchanged and should be retained for comparison.
Visible pixels at luminance 5 or below count as shadows, values at 250 or above count as highlights, and the remainder forms the usable range. Existing alpha values remain available to the documented operation. The method does not infer subjects, restore missing detail, calibrate a display, or develop raw camera data. Compare fine edges, gradients, text, texture, and transparent pixels with the original before relying on the result.
Endpoint counts are descriptive thresholds, not exposure diagnosis, HDR analysis, recovered detail, print proofing, or a quality pass/fail decision. 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. Results depend on browser decoding and encoding support. Animation, raw development, ICC calibration, layer editing, and batch processing are outside this tool's verified scope.