If you are planning to redecorate a room in your Georgian, Victorian or Edwardian period house and you have a computer, film camera and computer scanner, or a digital camera, you can experiment with a photograph to see the general effect of different colours.
The steps are:
In these graphics programs, colours are coded using one of a range of colour models. A common one is 'RGB' ie red-green-blue'. Each colour is represented by three numbers from 0 to 255. Thus black is 0-0-0 whereas pure red is 255-0-0, and white is 255-255-255.
If you have a manufacturer's paint card, scan it in and use the picker tool in your graphics program to find out the code for a colour you like.
If you have a drawing program, like Xara Xtreme or CorelDraw, rather than a paint program, you can trace the edges of, for example, the wall, and then fill it with the new colour.
Note that this is not an exact science; the colour on your computer screen will not match a swatch exactly because of the screen and because of the swatch printing process. And the colour on your wall will look different depending on the base coat and on lighting in the room. However, it will give you an idea!
These colours are typical of the Victorian period. These and others are shown below: