### Table of Contents - [background](#background) - [greyscale](#greyscale) - [grayscale](#grayscale) - [toColourspace](#tocolourspace) - [toColorspace](#tocolorspace) ## background Set the background for the `embed`, `flatten` and `extend` operations. The default background is `{r: 0, g: 0, b: 0, alpha: 1}`, black without transparency. Delegates to the _color_ module, which can throw an Error but is liberal in what it accepts, clipping values to sensible min/max. The alpha value is a float between `0` (transparent) and `1` (opaque). **Parameters** - `rgba` **([String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String) \| [Object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object))** parsed by the [color](https://www.npmjs.org/package/color) module to extract values for red, green, blue and alpha. - Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameter Returns **Sharp** ## greyscale Convert to 8-bit greyscale; 256 shades of grey. This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use `gamma()` with `greyscale()` for the best results. By default the output image will be web-friendly sRGB and contain three (identical) color channels. This may be overridden by other sharp operations such as `toColourspace('b-w')`, which will produce an output image containing one color channel. An alpha channel may be present, and will be unchanged by the operation. **Parameters** - `greyscale` **[Boolean](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** (optional, default `true`) Returns **Sharp** ## grayscale Alternative spelling of `greyscale`. **Parameters** - `grayscale` **[Boolean](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean)** (optional, default `true`) Returns **Sharp** ## toColourspace Set the output colourspace. By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels. **Parameters** - `colourspace` **[String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)?** output colourspace e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L568) - Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters Returns **Sharp** ## toColorspace Alternative spelling of `toColourspace`. **Parameters** - `colorspace` **[String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)?** output colorspace. - Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** Invalid parameters Returns **Sharp**