M E G A P I X E L . R O: Using Curves in Photoshop

If you have taken pictures with your camera lately, or are hunting for artistic images online and can only find photos with poor contrasting and little vibrancy - this tutorial is for you.

There are many photoshop tutorials focusing on curves - and so I would like to hopefully please you by giving you a brief detail of what exactly curves are, why they are useful, and how you can use them. I will then proceed on to notifying you of some famous curve techniques used by many such as the 'S-Curve'.

Curves in Adobe Photoshop, are designed to help improve the contrast in your pictures, emphasize shadows, highlights or midtones, and generally increase the style of the photo. Don't be put off by the jargon, applying curve changes are extremely easy to do and fun to mess around with. They are also extremely useful for black and white images and along with 'levels' make editing of greytone snaps easy.

I will begin by demonstrating how images can be altered to change the look and feel of the picture. Below this is a picture of outback America. As you can see the tree is the main part of the picture and the green trees behind it suggest a healthy amount of rainfall and nutrients.

However, I want this picture to reflect a harsh dry land, with dry hot days. To do this you can do the following:

Download the image and open it with photoshop.
Locate the 'Image' section in photoshop; go down to 'Adjustments' and in the sub-menu select 'Curves'
A new window should open displaying 'Curves' as the title. You should see a histogram displayed inside of the window - this controls the highlights, midtones and shadows. You need to edit this by making two nodes to form a 'S' like shape. This can be seen below.
Ignore the 'input' and 'output' box displayed - this is for precision, but the units shown are only based on one node, I suggest ticking the 'preview' box so that if your result does not please you, you can make minor alterations quickly.
Once you are done, simply press the 'OK' button and your image is complete. The picture should now look a lot more intense, and the landscape itself drier. Below is my result

Example Of Curves

Below I have constructed an animated example of curves using Adobe Flash. If you do not have flash you can download it here. You can edit the picture below by clicking on the nodes of the histogram.

I hope this creates a fair reflection for as to how curves work. If you are still unsure, there are some more diagrams below showing what would happen to a simply 2 colored document when the curve technique is applied differently. After that I will explain an overall explanation for curves.

I will now display images below showing the colors being affected and I will show the curve next to it.

So you can see how these colors are effect - but why does it happen? Why does it work in this way? The following diagram will show a general rule for what happens to a colour when it is changed using curves. Below it you will see another images showing how this happens.

These pictures show the changing effects when you alter the graph. As you can see, the orange line does not correspond equally with the graph above - to make the effects of the line you would have to alter the graph to look like below.

The line above would change any colour with the brightness of the 'input' colour and transform it into having the brightness of the 'output' colour. With my example above, the colour would get darker. I hope this is understandable to you - if it is not please do some more testing with the flash demo above to get a grasp of the concept. Thank you very much for viewing this tutorial - if you have any comments / queries / need help please don't hesitate to contact me via either the forum. Alternatively you can email me at