You may have seen very old monochrome prints that were more of an orangey-brown colour than black and white and wondered about creating that attractive effect yourself.
Originally staining from the chemicals used to process the print caused the colour.
Then when more modern chemicals were able to produce cleaner black & white prints from the darkroom, the wheel was re-invented and dyes were made available to the darkroom enthusiast to re-create this nostalgic, yesteryear effect.
And then along came digital photography and what happened? Some digital cameras allowed you to specify 'sepia', as well as straightforward black & white as an option for your photographs! The only problem with this was that if you chose sepia you couldn't change your mind later on and go back to full colour.
However, if you take all your images in full colour, then in your digital darkroom (Photoshop or other image editing software) you can create black and white and sepia and do all sorts of other strange things to your images - some of them actually useful, rather than just fun.
So I will show you a very quick way to create a sepia effect you can be proud of even if you are a newcomer to all this digital imaging.
It is not the only way you can do it, but it is simple, straightforward, and will introduce you to a few techniques that may prove useful in other areas of digital imaging.
Obviously you need to select a colour image that you would like to convert to a sepia-toned monochrome effect.
The following description is based around Photoshop, but other image editors should have comparable commands.

1. Themost important thing to do first is to go to 'Save As', usually in theFile menu, change the name of your image, and click Save.
   This creates acopy of your image to work on so if you accidentally screw it up, you cango back to your original and start again.
   
2. Thenext step is to create a monochrome image.
   Go to the Channel Mixer andtick the monochrome box.
   
3. Nowyou will find you have a black & white image but if you play with thered, green, and blue sliders you can change the tones in the picture.
   Forinstance if you increase the red and decrease the blue you will darkenblue skies and pull out more detail in the clouds.
   
4. Whenyou are happy with this create a new layer and call it Sepia.
   
5. Selectthe whole of the layer (easiest CTRL+A)
6. Choosethe fill tool (paint can) and find yourself a colour (double-click on theforeground colour box in the toolbar) that you want to use for the tint(you might start with the values R=195 G=153 B=101, you can type thevalues next to the letters) hold the paint can over the layer and click.
   You should now have filled the whole of the layer with a nice browneycolour.
   
7. Goto the Layers palette, click on the sepia layer to select it, then go tothe blend mode drop down list (showing normal) and select Colour from thelist

You should now have a 'sepia', or any colour you chose for the fill layer, toned image.
If the 'sepia' colour is a little strong then just reduce the opacity of that layer.