What does a histogram tell me about my image?

A histogram shows how pixel brightness is distributed. Peaks on the left indicate dark areas; peaks on the right indicate bright areas. A well-exposed photo typically has values spread across the full range.

What is luminance vs. individual channels?

Luminance represents overall perceived brightness (combining R, G, B with human-vision weighting). Individual channel histograms show tonal distribution for each color independently.

Is my image uploaded to a server?

No. All processing happens entirely in your browser using the Canvas API. Your image never leaves your device.

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Image Histogram Viewer

Upload an image and visualize its RGB and luminance channel histograms with statistics.

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このツールについて

Upload any image to see per-channel histograms rendered on an HTML canvas. Toggle the Red, Green, Blue, and Luminance channels on or off individually. Statistics include mean, median, standard deviation, and the darkest and brightest pixel values for each channel. Useful for photographers, designers, and developers who need to understand an image's tonal distribution.

使い方

1 Click 'Upload Image' and select a JPEG, PNG, or WebP file.
2 The histograms for R, G, B, and Luminance channels render automatically.
3 Use the toggle buttons to show or hide individual channels.
4 Review the statistics table for mean, median, standard deviation, and min/max values per channel.

このツールについて

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