Teach_Yourself_Photoshop_Elements_2

THE MOST IMPORTANT THINGS YOU’LL EVER DO TO A PHOTO

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n chapter 2 we showed how Photoshop Elements’

automatic enhancement commands enable you

to fix exposure problems with a click. Commands

such as Auto Levels work their tone-tweaking

magic by reading and adjusting a photograph’s histogram.

A histogram is an undulating graph that shows the spread

and strength of the shadows, midtones and highlights in a

particular shot (much like a medical chart can tell a doctor

about the health of a patient). The histogram of a correctly

exposed photo will display a graph that spreads from the far

left (where the shadows are represented) to the far right

(where the highlights are represented).

The concept of histograms may sound a bit daunting, but

they’re the key to overcoming exposure-related problems.

We explain how to read histograms below, and then move

on to adjusting them to fix exposure problems.

Fix exposure errors

Fix over- or under-exposed images by adjusting their

levels to create healthier looking histograms

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Fix automatically

Choose Enhance>Auto Levels and the histogram graph

slides towards the left, turning some of the murky

midtones into strong dark shadows. This creates a healthier

histogram and a correctly exposed shot. On the following

pages we’ll show you how to manually adjust a histogram.

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Look at the levels

Tones are described by levels. The darkest shadows

should have a level of 0. The brightest highlights

should have a level of 256. If you place the cursor at the left

of the graph, you’ll see that this photograph’s darkest

shadows have a level of 35 or so.

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Analyse the tones

The histogram describes all the tones in the image. The

graph for this over-exposed image is squashed towards

the middle and right of the histogram, with no information

on the left. This indicates that the photo consists mostly of

midtones and highlights, and lacks shadows.

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Open the histogram

Open ty_elements08.jpg. We can see with the naked eye

that the shot is over-exposed. To see the spread of tones

in a more mathematical way, go to Window>Histogram. This

displays the tones of each colour channel as a separate graph.

To simplify it, set the Channel menu to RGB.

GET THE START FILES HERE: http://bit.ly/type-files