# ColToGrey: Convert Colors to Grey/Grayscale In DescTools: Tools for Descriptive Statistics

## Description

Convert colors to grey/grayscale so that you can see how your plot will look after photocopying or printing to a non-color printer.

## Usage

 ```1 2``` ```ColToGrey(col) ColToGray(col) ```

## Arguments

 `col` vector of any of the three kind of R colors, i.e., either a color name (an element of colors()), a hexadecimal string of the form "#rrggbb" or "#rrggbbaa" (see rgb), or an integer i meaning palette()[i]. Non-string values are coerced to integer.

## Details

Converts colors to greyscale using the formula grey = 0.3*red + 0.59*green + 0.11*blue. This allows you to see how your color plot will approximately look when printed on a non-color printer or photocopied.

## Value

A vector of colors (greys) corresponding to the input colors.

## Note

These function was previously published as `Col2Grey()` in the TeachingDemos package and has been integrated here without logical changes.

## Author(s)

Greg Snow <greg.snow@imail.org>

`grey`, `ColToRgb`, dichromat package

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```par(mfcol=c(2,2)) tmp <- 1:3 names(tmp) <- c('red','green','blue') barplot(tmp, col=c('red','green','blue')) barplot(tmp, col=ColToGrey(c('red','green','blue'))) barplot(tmp, col=c('red','#008100','#3636ff')) barplot(tmp, col=ColToGrey(c('red','#008100','#3636ff'))) ```

### Example output

```
```

DescTools documentation built on June 17, 2021, 5:12 p.m.