---
canonical: https://amplience.com/developers/docs/apis/media-delivery/media-delivery-reference/image-adjustments/
title: Image adjustments
  interactive: true
description: Adjust images with Amplience Dynamic Media using the Media Delivery API - colour space, sharpening, composite modes, background colour, blur, noise reduction, gamma, hue, saturation, and brightness.
keywords:
  - Dynamic Media
  - Media Delivery API
  - Dynamic Media image adjustments
  - unsharp mask
  - Gaussian blur
  - background colour
  - composite mode
  - hue saturation brightness
audience: Developer
date_published: 2026-07-12
date_modified: 2026-07-27
---

# Image adjustments {#image-adjustments}

Change how an image looks without changing its dimensions, using the Media Delivery API. These parameters cover colour space, sharpening, blur, noise reduction, gamma, background fill behind transparency, and the hue, saturation, and brightness controls.

> **Note: Base URL pattern**
> The parameters on this page are appended to a Dynamic Media image URL. For the URL pattern and how parameters chain together, see the [Media Delivery API guide](https://amplience.com/developers/docs/apis/media-delivery/media-delivery-reference/).

## `cs` — Color space {#cs}

Changes the colour space of the image.

| Value | Description |
|---|---|
| `rgb` | RGB |
| `rgba` | RGBA |
| `srgb` | sRGB |
| `gray` | Greyscale |
| `cmyk` | CMYK |
| `ohta` | OHTA |
| `lab` | LAB |
| `xyz` | XYZ |
| `hsb` | Hue, saturation, brightness |
| `hsl` | Hue, saturation, lightness |

```uri
https://cdn.media.amplience.net/i/ampproduct/woman-checked-skirt-striped-bag?cs=rgb
```

## `unsharp` — Sharpen {#unsharp}

Sharpens the image by applying an unsharp mask, a standard image-processing technique that increases edge contrast.

Format: `unsharp={radius},{sigma},{amount},{threshold}`

| Component | Range | Description |
|---|---|---|
| `radius` | 0–5 | Gaussian filter radius. `0` lets the system choose. |
| `sigma` | 0.01–5 | Gaussian standard deviation |
| `amount` | 1–300 | Percentage difference. Values above 100% are valid. |
| `threshold` | 0–255 | Brightness threshold for sharpening |

```uri
https://cdn.media.amplience.net/i/ampproduct/casual-curly-curly-hair-794064?w=500&unsharp=2,1,160,0
```

> **Tip:** Set `amount` to 1 to see the image with virtually no sharpening applied, then raise it again to compare.

## `cm` — Composite mode {#cm}

Defines the composite operator when an image is applied on top of a background colour. This controls how the two are blended where they overlap - `over`, the default, simply places the image on top.

Supported values: `over` (default), `colo`, `dark`, `diff`, `light`, `multi`, `cout`, `cover`, `copy` (see [`cm=copy`](#cm-copy))

```uri
https://cdn.media.amplience.net/i/ampproduct/brown-shoe-image?cm=over&bg=rgba(0,102,204,0.5)
```

## `cm=copy` — Remove alpha channel {#cm-copy}

Removes the alpha channel from an image, leaving the colour data that was masked by the alpha channel visible.

> **Info:** This feature must be provisioned on your account. To use `cm=copy`, contact your Customer Success Manager or Amplience Support.

**Example:**

```uri
https://cdn.media.amplience.net/i/ampproduct/brown-shoe-image?cm=copy
```

## `bg` - Background colour {#bg}

Sets the canvas background colour. Takes effect when the image is padded (`upscale=padd`) or the source image is transparent.

This example uses a transparent source image, so the colour fills behind the alpha channel. For the padded-canvas case, see [`upscale=padd`](https://amplience.com/developers/docs/apis/media-delivery/media-delivery-reference/sizing-and-scaling/#upscale).

```uri
https://cdn.media.amplience.net/i/ampproduct/brown-shoe-image?bg=rgb(226,216,202)
```

> **Tip:** The parameters here set the background colour at delivery time and never alter the master asset. To change the background of the asset itself as part of an automated workflow, use the [Fill background](https://amplience.com/developers/docs/workforce/flows/action-reference/image-actions/#fill-background), [Normalize background](https://amplience.com/developers/docs/workforce/flows/action-reference/image-actions/#normalize-background) and [Remove background](https://amplience.com/developers/docs/workforce/flows/action-reference/image-actions/#remove-background) actions in Workforce flows.

## `blur` - Gaussian blur {#blur}

Applies a Gaussian blur to the image. This softens detail evenly across the image, in the same way as the blur tool in a photo editor - the higher the `sigma`, the stronger the effect.

Format: `blur={radius},{sigma}`

| Component | Range | Description |
|---|---|---|
| `radius` | 0–100 | Accuracy of the blur. Generally 2–3× sigma. |
| `sigma` | 0–100 | Strength of the blur |

```uri
https://cdn.media.amplience.net/i/ampproduct/brown-shoe-image?blur=30,60
```

## `noiser` - Noise reduction {#noiser}

Removes noise from the image. Value is between 0 and 5. Higher values remove more noise but also smooth away more fine detail - noise reduction is always a trade-off between grain and sharpness, so use the lowest value that cleans up the visible noise.

This example uses a deliberately grainy source image, rendered at 500px so the grain stays visible in the preview. Drag to `0` to see the untouched grain, and above `3` to see the detail cost of heavy noise reduction:

```uri
https://cdn.media.amplience.net/i/ampproduct/two-friends-on-deck-grainy?w=500&noiser=2
```

## `gamma` - Gamma correction {#gamma}

Adjusts the gamma of the image. Values below 1.0 darken the image; values above 1.0 lighten it.

```uri
https://cdn.media.amplience.net/i/ampproduct/two-friends-on-deck?gamma=0.5
```

## `hue`, `sat`, `bri` - Hue, saturation, brightness {#hue-sat-bri}

Adjusts the colour properties of the image. Each parameter can be specified independently. Values range from -100 to 100.

| Parameter | Description |
|---|---|
| `hue` | Shifts the colour based on the [hue scale](https://upload.wikimedia.org/wikipedia/commons/a/ad/HueScale.svg) |
| `sat` | Adjusts the amount of grey (colour saturation) |
| `bri` | Adjusts the brightness |

```uri
https://cdn.media.amplience.net/i/ampproduct/girlwithballoons?w=800&hue=25&sat=20&bri=10
```

> **Tip:** Adjust one slider at a time with the other two at 0 - `hue` in particular shifts every colour in the image at once, so small changes go a long way.