Channel & Levels Explorer
Split an image into its red, green, blue and alpha channels, stretch the contrast and posterise it to make faint hidden shapes visible.
You can also drag an image here, or press Ctrl+V to paste a screenshot.
Finding text hidden in a single colour channel
A lot of puzzle images hide their answer in a way that is technically visible but practically invisible: text painted one or two shades away from the background, a shape that exists only in the blue channel, or a layer sitting in a PNG’s transparency where no ordinary viewer will show it.
Auto levels takes whatever narrow band of brightness the image actually uses and stretches it across the full range, so a difference of one step becomes the difference between black and white. If an image looks like a flat rectangle of colour, this is the button to press.
Splitting the channels matters because a message written in a single primary colour disappears into a busy picture but stands alone when that channel is viewed by itself. Try each of R, G and B in turn before concluding an image is clean, and check A too. Transparency is a common hiding place, precisely because it survives being posted to a cache listing.
Nothing here is uploaded. The image is decoded and processed by your own browser, so it's fine to use this on an unpublished cache image.