By Rutt

Introduction This tutorial explains a recipe that can make almost any picture more dramatic and appealing. It uses some very advanced techniques in simplified, stylized ways. Because of this, anyone with Photoshop version 5 or later has the tools to use this technique.

The tutorial is in two parts. I will walk you through the recipe, showing it's application to a particular image. Then I will explain why it works. You don't actually need to know why this works in order to use it, but that understanding can lead you to more advanced techniques and a much more sophisticated understanding of the color and how to manipulate it in your images.

No Pop Here is the starting point. I took this picture on a rainy October afternoon in Vermont. There's a lot about it I do like, but it's pretty drab, not really worth a second look the way it is. I remember the colors quite differently. In my memory the greens were very deep, like the emerald greens of Ireland. The barn was red, not brown. The sky was much more interesting and varied between low clouds and bluer areas. In fact, everywhere I looked, I saw more color variation, more contrast and more detail. That's the pop I wish this picture had.

Quick Start For those who are already somewhat familiar with Photoshop, here is the basic recipe. I'll walk though the steps in some detail below, so if you need more help, just skim this list of steps and then use it as a guide to the detailed explanation below.

1. Convert to the LAB color space
2. Curves
3. Steepen A and B channels symetrically by bringing in the endpoints of each curve toward the center equally. After this, the curve (line actually) will still cross the center horizontal center at the vertical center. Start out by experimenting with bringing in each end point between 10% and 20%.
4. Establish light and dark points by moving the endpoints of the L curve inwhard. Optionally, steepen the L curve through the areas where the detail is of most interest.
5. Activate only the L channel
6. USM, trying the values 200, 1.0, 10

Details If any or all of that went over your head, don't panic! I'm going to go over it in excrutiating detail. Follow along and you'll easily be able to apply this recipe to your own images.

1. Convert to LAB
The figure shows how to do this. Click on the Image menu, then the Mode submenu, and finally on the Lab Color item.

2. Open the Curves dialog The figure shows how. Click on the Image menu, then the Adjustments submenu, and finally on the Curves item. The key sequences to the right of the menu show shortcuts which you can use instead of the mouse. In this case Command-M on a Mac or Alt-M on windows would also bring up the curves dialog.

3. Steepen the A and B curves
The curves dialog allows you to alter your image in each channel of it's current color space. In this case, the image has been converted to LAB and has three channels, Lightness, A, and B. You can change which of these the curve applies to by clicking on the Channel dropdown and selecting an item. For now I am going to work with the A and the B curves.

Exactly what I am going to do with these curves is to make them steeper by dragging each endpoint toward horizontally toward the center while keeping it at the bottom or the top of the graph.

It's important that I have steepend the curves symetrically and equally.

The steepening is symetrical in that the two endpoints of each curve have been moved inward by exaclty the same amount, in this case 15%. The center of the line still crosses the midpoint of the graph. For now, treat this as a matter of revealed truth, the 11th commandment.

The steepening is equal in that I have done exactly the same thing to both A and B curves.

At this point the image starts to come alive. There is a lot more variation in the colors. The barn is looking redder. The individual leaves of grass and the vegetation in the trees is more differentiated.

You should experiment with just how much steepening you use in this step. Initially, try values between 10% and 20%. Eventually, you'll be able to estimate good values just by looking at the original.

How to work with curves
So far, so good, but the next step requires a little more dexterity with the curves dialog, so I'm going to take you on a little detour and explore a few of its features.



Curves Preview
The figure shows the mouse over the Preview check box. Clicking this off and on shows the image before and after the curve is applied. Get used to using this a lot. It's the best way to see where you are going and to make mid course corrections.

Getting lightness on the left and darkness on the right



This step isn't strictly necessary, but it's easy and avoids confusion. The curves dialog has two possible orientations. The bottom right can either be the lightest or darkest possible point along both dimensions. It has become customary to write about these curves with the orientation as shown. If it is the opposite, click on the double arrow in the center of the horizontal axis legend (as shown) to reverse it.

Using the Curves Dialog to measure points in your image
This feature is the great secret of being able to use curves well. With the curves dialog open, click the mouse on any spot of your image and a point will appear on the dialog showing the value of the color at the spot on the curve. Drag the mouse cursor (move it with the mouse button (right mouse if you have more than one mouse button) held down, and the point will move along the curve to show the value dynamically. I am about to make very good use of this feature in order to implement the next step of the recipe.



4. Establish light and dark points
Generally, images look best when they use the full range of available contrast. That means that they have a darkest spot which is truly black and a lightest spot which is truly white. It's actually quite a bit more complicated than that, but it's easiest to understand by doing than by theorizing. I used the Channel drop down to switch to the Lightness channel of the curves dialog. Then I used the mouse to look around for the lightest point I could find in the image. It's in the clouds. You can see that it's about 5% above the 0,0 point of the graph, meaning that it isn't as light as it could be.