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---
title: images.Sigmoid
description: Returns an image filter that changes the contrast of an image using a sigmoidal function.
categories: []
keywords: []
action:
aliases: []
related:
- functions/images/Filter
- methods/resource/Filter
returnType: images.filter
signatures: [images.Sigmoid MIDPOINT FACTOR]
toc: true
---
This is a non-linear contrast change useful for photo adjustments; it preserves highlight and shadow detail.
The midpoint is the midpoint of contrast. It must be in the range [0, 1], typically 0.5.
The factor indicates how much to increase or decrease the contrast, typically in the range [-10, 10] where 0 has no effect. A positive value increases contrast, while a negative value decrease contrast.
## Usage
Create the filter:
```go-html-template
{{ $filter := images.Sigmoid 0.6 -4 }}
```
{{% include "functions/images/_common/apply-image-filter.md" %}}
## Example
{{< img
src="images/examples/zion-national-park.jpg"
alt="Zion National Park"
filter="Sigmoid"
filterArgs="0.6,-4"
example=true
>}}
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