---
title: BWMode
summary: BWMode specifies how the image should be converted to black and white duotone.
url: https://www.fastly.com/documentation/reference/compute/sdks/go/compute-sdk-go/fsthttp/imageopto/struct.BWMode/
---

**Kind:** Struct  
**Module:** [imageopto](https://www.fastly.com/documentation/reference/compute/sdks/go/compute-sdk-go/fsthttp/imageopto/)  
**Package:** compute-sdk-go v1.11.0  
**Source:** https://github.com/fastly/compute-sdk-go/blob/d6bf71b04516ed72d6018cab6fff701a865f86e5/fsthttp/imageopto/imageopto.go#L384

```go
type BWMode struct {
	// contains filtered or unexported fields
}
```

BWMode specifies how the image should be converted to black and white duotone.

## Methods

### String

**Source:** https://github.com/fastly/compute-sdk-go/blob/d6bf71b04516ed72d6018cab6fff701a865f86e5/fsthttp/imageopto/imageopto.go#L406

```go
func (bw *BWMode) String() string
```

**Returns**

`string`