Bringing out detail

Bringing out detail

There are ways for bringing out detail in a digital capture file or a scan.

A photograph taken in bright sunlight with strong shadows is most unlikely to create a good print. The contrast will just be too great and even some of the detail that is there in the image can be lost in the print.

The original digital capture or scan might have more detail within it that is not apparent at first sight.

The Shadow / Highlight command can help here, although it has limitations as far as quality is concerned.

Shadow/Highlight

� Find an image which has problems of excessive contrast, such as heavy shadows and highlights which appear to be lost.
The image on the right is missing detail in the highlights in the top left corner and has strong shadows inside the tractor.

� Go to Image > Adjustments > Shadow / Highlight.
Firstly, check the Show More Options box in the bottom left corner to open the dialogue box fully.

� We'll start with the shadows, so have the Highlights Amount slider is set to zero.

� The shadows need a lift but too much will spoil all the atmosphere.
In the Shadows section, the Amount slider is set to 26%.

� Tonal Width controls the range of tones which will be adjusted.
A low value will cover only the darkest of shadows.
The higher the setting, the more the selected range creeps into the midtones.

The default setting is 50%, but in this case the Tonal Width slider is moved down to 22%.

� Radius determines how far around each pixel the effect works.
A low settings will mean a small local influence.
A high setting will include many more of the neighbourhood pixels.
The higher setting means the lightening becomes much more general and no longer specific to the lower shadow areas.

Radius and Tonal Width work together and they need to be adjusted as a pair to give the best balance.
In this case, a Radius of 124px works with a Tonal Width of 33%.
The effect can be judged by toggling Preview on and off.

A bigger problem with this image is the loss of highlight detail in the top left corner.

� In the Highlights section, moving the Amount slider up to 58% improves that corner considerably.

� A Tonal Width of 42% and a Radius of 146px seem to give a good balance.

Although the settings are a matter of taste, there are some factors to be considered.

A Tonal Width value which is too high will introduce halos around very dark and very light areas.
If Shadows and Highlights Amounts are set too high, this can also produce halos.
As well as the wrong settings producing halos, they can also flatten contrast in the target areas too much.
A high or even a maximum Radius setting helps protect against unwanted halos and avoid the risk of any posterization appearing.

Color Correction affects the areas which have just been adjusted.
After using the Shadows adjustments, areas which were dark can now be seen. Their colours might be too dull or too strong and the Color Correction slider will change their saturation, not change their colour, in spite of the name of the slider.

With only a little change of the Shadows and Highlights, Color Correction will offer only a small range of adjustment.

For Greyscale images, this slider changes to Brightness.

Midtone Contrast will increase or decrease the contrast of the modified shadow and highlight areas.

The Black Clip value determines what portion of the shadows turns to complete black with no detail.
With a setting of 1%, anything from shadow level 1% to 0% will be pure black.

With the White Clip, anything from highlight value of 1% to the brightest level of 255 will be pure white, or a specular highlight containing no detail. The higher the percentage value, the brighter will be the highlights.

The higher the values set here, the higher will be the contrast of the adjusted areas.
If in doubt, leave the default settings of 0.01%.

photoshop cs4 tutorials Tip
When the Shadow / Highlight command is first opened on a new image, it will open at the default settings. These are designed to correct images with strong backlighting � where the foreground subject is in shadow and the background is in bright sun. In such cases, the settings might work fine as they are without further changes.

photoshop cs4 tutorial The Shadow / Highlight command is very good for minor corrections on small areas and perhaps is at its best for backlit subjects.

Whatever the company blurb might say, large corrections can cause a loss of image quality and other methods of bringing out detail and retaining detail can be better.

The Best Methods

The best methods for bringing out highlight or shadow details involve processes which are more manual.
Techniques using Color Range, Advanced Blending and Layer Masks have been used for some years by astronomer photographers where images from space can contain an enormous tonal range.

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These techniques can also be done on older versions of Photoshop where the Shadow/Highlight function does not exist.

Here are before and after illustrations of an image rescued with the Color Range method.

Although they are not too complicated, the techniques are somewhat beyond the basics and so a bit outside the intended purpose of this site.
They are all covered comprehensively in Photoshop In A Day , with illustrations and sample images.

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