Freelance Photographer
Seeing things differently
A taker of Photographs - A creator of images

There are certain times when the lighting situation can fool a camera’s meter in to giving a false reading... The camera calculates that all scenes are an average 18% grey, which of course we all know they are not... Predominantly white objects, or scenes that have a lot of reflected light like snow scenes, water scenes, beach scenes, or landscapes with a lot of sky in them cause under exposure... Very dark scenes tend to over expose the image as the camera tries to lighten these to 18% grey...

Below you will see an image which is predominantly white, a white sign on a white door... I deliberately made no ‘in camera’ compensation and as you can see the result is less than acceptable... The cameras meter has been fooled by the brightness of the scene and rendered the image about 2 stops under exposed... You will also see from the histogram below there are no true whites in this image but there are ways of trying to correct this in Photoshop, some better than others... I will try to explain the methods I know and show you the results for you to compare...

Auto contrast...

This is one of the easiest methods to save this under exposed image and it takes just a few mouse clicks...

1... Click on Image from the Menu bar...

2... Select Adjustments...

3... Click on Auto Contrast...

This does a pretty good job but the only problem with this method is because it´s an auto adjustment you have no control over the final outcome... This method in my opinion still leaves this image slightly under exposed and more adjustment is needed...

Auto levels...

This is another easy method to save the image, the steps are practically the same as for auto contrast...

1... Click on Image from the Menu bar...
2... Select Adjustments...
3... Click on Auto Levels...

This method also does a pretty good job but again the problem with this method is because it´s an auto adjustment you have no control over the final outcome... This method in my opinion also still leaves this image slightly under exposed and more adjustment is needed...

Curves...

This method can give very reasonable results with care...


1... Click on layers tab or press F7...
2... Click on the New Adjustment layer icon shown below...

3... Select Curves...
4... Click and hold the left mouse button down on the diagonal line and drag it up and left until you achieve the desired correction...

Of course if this was an over exposed image you would Click and hold the left mouse button down on the diagonal line and drag it down and to the right... You can also select different points and create a sine curve to alter the effect...

Levels...

This is my preferred method as it gives me complete control over the amount of adjustments to both blacks and whites...

1... Click on layers tab or press F7...

2...0Click on the New Adjustment layer icon shown below...

3... Select Levels...
4... Move the white slider on the right, as shown below, towards the left until you achieve the desired correction...

Of course if this was an over exposed image the histogram information would be bunched to the right of the image and you would move the black slider to the right... The central grey slider can be moved in either direction to balance out the mid-tones giving even greater control...