How to duotone in photoshop ?

This article deals with how to do duo tones in photo shop.Let us first see about the concepts of duo tones in photo shop.Duo tones can be any 2 colors . It needn't be black and white alone.Yes , it can be any two colors.
Duotones seems to have little bit of trouble while printing. Its because you cannot actually predict the results on a consumer printer.For this to work you need to have color proofing system. This should be capable of substitution CMYK with real PMS.It is to be noted that only a few printers support this feature.

How duotone effect is achieved ?
Duo tone effect is achieved by imaging the two negatives with different tonal ranges.

Photoshop's default duotone settings can be accessed by clicking load in duotone options menu.

How to make duotone?

If the current photo is in color convert it to gray scale.
After that select duotone settings from Image menu : mode :duotone.
You can preview using preview option.Choose duotone from popup type menu.
Select color using color picker.
You can save the document.

We have seen about concepts of duotones, its dependence on printer, selecting duotones etc.