Adjust Levels for Numeric Samples
Remap a list of tone values with explicit input black/white points, midtone gamma, output levels, and optional endpoint clamping. Pure numeric math; no upload.
About this tool
Levels adjustment is the classic black-point, white-point, and gamma transfer curve used in photo editors. This tool applies that same deterministic math to a list of numeric samples rather than to a raster image. Paste tone values, luma samples, sensor readings, or any other finite numbers, then choose the input range that should become the output range.
The formula is:
- Normalize:
(value - input_black) / (input_white - input_black). - If Clamp is on, clamp that normalized value to
[0, 1]. - Apply midtone gamma as
normalized^(1 / gamma). - Remap to
output_black + gamma_value * (output_white - output_black).
Worked example
Input values:
64, 128, 192
With input_black=64, input_white=192, gamma=1, output_black=0, and
output_white=255, the output is:
levels: input 64–192, gamma 1, output 0–255
0
127.5
255
Use gamma above 1 to brighten midtones, below 1 to darken midtones, and swap
output_black / output_white to invert values. This is a numeric transfer
function; it does not inspect image pixels, draw histograms, or auto-pick black
and white points.
FAQ
Is this an image editor?
No. It implements the Levels transfer math for numeric lists. If you already have pixel channel values or measurements, paste them here. Raster-image features such as histograms, eyedroppers, and per-channel previews are outside this pure numeric model.
What does gamma do?
Gamma controls the midtones after the input range is normalized. Values greater
than 1 brighten midtones; values between 0 and 1 darken them. The black and
white endpoints stay fixed when clamping is enabled.
What happens outside the input black and white points?
With Clamp enabled, values below the input black point become the output black level, and values above the input white point become the output white level. Disable Clamp to extrapolate beyond those endpoints instead.
Can I invert the values?
Yes. Set output_black higher than output_white, for example 255 and 0.
The input black point then maps to 255, input white maps to 0, and the values
between them are inverted along the same gamma curve.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool levels-adjust "0, 64, 128, 192, 255"New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/levels-adjust/?values=0%2C%2064%2C%20128%2C%20192%2C%20255&input_black=0&input_white=255&gamma=1&output_black=0&output_white=255&clamp=trueMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.