Imagine the ability to apply an effect to a group of layers in Photoshop, and then have the power to edit that effect later, while preserving the original layers. Adjustment Layers allow just that.

This is a professional looking, one colour effect.
1. Open your picture, in this example we used Mr. Michael Jackson!
2. First, we need to take away the colours and to reduce it to a two tone picture. So, click Image > Adjustments > Threshold. Give this a setting of 125 and hit ok...

This will teach you how to turn your image to greyscale, then bring certain parts back to colour.
1. Start with any picture. If you like, use ours... A landscape of a desert.
2. On your layers palate, click 'create new fill or adjustment layer' (see below) and click hue/saturation...

This effect is quite popular on forums, its not just as easy as taking the colour away...
1. Open your eye (click image for higher quality version to start with).
2. Desaturate (take out the colour) , by clicking Image > Adjustments > Desaturate...

How to turn your car, into a customised coloured ride! (All images in this tutorial are scaled down to around 50% and CAN ALL be enlarged).
1. Open your car in photoshop.
2. Now, grab the pen tool - make sure you have the "shape layers" button clicked as shown...

Choose any image, and open it in adobe. I used this one. Go to layer>>layer style>>gradient overlay. Use the settings below... Click on the bar beside Gradient. In the new window that comes up, you should see a large gradient bar close to the bottom...

Ever got a really good wallpaper for your computer, but didnt like the colour? Here I will show you how to change the main colour to get it just the way you like it :P
1. Get your wallpaper. I cut my examples from a wallpaper called extravaganza by urban effect which can be seen here...

1. Open Photoshop. Open Eagle.psd from samples folder. Adobe > Photoshop 7.0 > Samples.
2. To make it gray ( black & white ), no need to change the mode and convert it into Grayscale.
3. Image > Adjustments > Desaturate...

Upon request, here's how I added color to the eyes. First, 'Set the Foreground color' that you would like to make the eye's. (I used '#1B9DE7').Next zoom in on the picture and using the 'Elliptical Marquee Tool (M)' make two selections to cover both eyes, as I have captured below.

Here's simple 'Adjustment Layer' technique on how to alter a particular color within a photo. Below is the original photo I took of a mini car from my neighborhood. In this lesson I will use the adjustment layer 'Hue/Saturation' to do this. So please follow along...