Curves Adjustment for the Web

How to Adjust the Gray Tones in Your Photos for the Online Viewing

May 7, 2007

Image before adjustment, Timothy Dzurilla

The curve adjustment layer is slightly more complicated than levels. Effective use of this layer can really bring out the subtler details in your images.

Once you have cropped your photo and adjusted the blacks and the whites with the levels layer, this adjustment layer is used for adjusting the grays.

This is a more subtle effect, but for web photos, it will further enforce your subject and create a more dynamic picture despite smaller image sizes and file compression.

To Create a Curves Adjustment Layer

Like the levels adjustment layer it is possible to make this adjustment directly to your image through the Image menu, but it is preferable to create an adjustment layer so that changes can be made in the future, or so that you can limit the effect to specific parts of the image.

To add a curves adjustment layers:

1) At the bottom of the layers window, click on the icon that looks like a half white, half black circle.

2) Select the Curves.

3) You will see the adjustment layer appear above your image. If it is below, drag the layer to the top.

Curves

The mechanics of the curves layer is more complex than the levels layer. It is not necessary to understand exactly how it works to use. Understand that this layer adjusts the relationship between blacks and whites and can be used to manipulate the contrast between true black and white, or can be limited to adjust the contrast between shades of gray.

We will be increasing the contrast between light grey and dark grey to highlight details in our subjects which is especially recommended for photos of people.

Adjusting Curves:

1) Open the adjustment layer by double-clicking on it in the layers pane.

2) Create a point one block down and three blocks to the right by clicking on the line at that point.

3) Create another three blocks down and one block right by clicking on the line at that point.

4) We want to increase the slope between these two points to increase the contrast in our mid-tones. To do this, slide the top point slightly up, and the bottom point slightly down by clicking and dragging.

5) Check the difference by toggling the “preview” on and off.

6) You can also decrease the contrast in your mid-tones by moving the points in opposite directions.

Next we will adjust the hue and saturation of the colors in the image.