Enhance Tonal Value Separation in Primary & Secondary Hues

How To:

Enhance the tonal values of a full colour images various hues with the Photoshop CS3 Black and White Image Adjustment command.

The Black and White image adjustment command introduced in Photoshop CS3 is intended to simplify the process of creating pleasing monotone conversions from full colour images. The old technique made famous by Russell Brown used to be performed using two Hue/Saturation adjustment layers and blending modes. The goal of using the Photoshop CS3 Black and White command for full colour image editing is to increase tonal variation in the full colour RGB image, via a luminosity blend. If using a command designed for making black and white images on a full colour image seems unintuitive, then it may help to think of this edit as a L edit in LAB mode rather than an RGB edit. This technique is particularly useful for processing images of landscapes, where one may wish to add drama to the sky or to enhance the appearance of foliage. Although there are other ways to this end, the Black and White command set to Luminosity blend mode provides a fast interactive means of image enhancement.

Luminosity Blending of the Black and White Command

1. Add a new Black and White adjustment layer to the full colour RGB image - set the layer blending to Luminosity mode.

 Adjusting the Various Image Hues

2. Adjust the hue sliders to create high contrast separation between critical hues (this is both a visual process and one evaluated via the info palette numerical readings and or colour samplers).

Tip #1:

It is advised that one use a wide gamut RGB editing space such as ProPhoto RGB when performing a Black and White adjustment in luminosity blend mode - to reduce and or remove artifacts such as posterization caused by the edits to the various hue ranges of the image when combined with the luminosity blend (wide gamut RGB editing spaces often require higher bit modes than 8 bpc).

Tip #2:

The background image layer can be duplicated below the Black and White adjustment layer and set to Color blend mode and noise reduction can be applied to the colour component of the image to reduce grain, noise and other individual channel artifacts.