Part 4 :- Using USM (Unsharp Mask) to add contrast to an image.

In this part, I am using the USM tool to add contrast to an image.

This is the original image I wish to 'enhance'.

Notice I have the 'Info' box open at top right corner. This is so I can keep track of how much affect my adjustments have on highlight areas as we do any adjustments. More on that in a moment.

Note : I can use a similar approach for checking shadow affect also. In CS2, I can have up to four sample points selected.

In this particular process, I am not using a Layer, however, this can also be done in a Layer.

Step 1 - Select and apply Despeckle.

Note : As I am going to apply quite a degree of sharpening, I wish to 'soften' some of the image before I start. This will also help minimise the effect on any noise I may also 'enhance' in the process.

Step 2 - Now for the reason why the Info box is open.

Select the Color Sampler Tool.

Step 3 - Using the Color Sampler Tool, I have placed two sample points on the image in 'hot' areas to measure their RGB value.

You can see the values in those areas in the Info box 1R = 215, 213, 244 and 2R = 243, 242, 255.

Even though the camera did an excellent job in retaining highlights, as you can see the blue channel in 2R has 'blown away' already. Not a big deal as it is a miniscule part of the image. What we don't want is the other channels, or areas, sharing a similar fate.

Note : Placing these sample points will now allow me to keep track of my changes on the highlights, as I make adjustments.

Step 4 - Select the Unsharp Mask (USM).

Step 5 - Select values for USM.

Here I am being very aggressive with my values and, if you check the Info box, you will see I have lost all detail in my RGB channels in these highlight areas.

Don't panic, we'll fix this soon.

Note : Using the Info box in this manner, shows me the original values for each position at left and the change at right.

Step 6 - Select Fade Unsharp Mask.

Step 7 - Select the fade option - Fade/Soft Light.

A new dialogue box appears and we select Soft Light as the mode in which we wish to 'fade' the effect of the USM application.

Step 8 - Select the value of Opacity for Fade.

Note : As you make adjustments here, keep an eye on what is happening in the Info box. A maximum value of 248 would be as far as we wish our highlight values to reach. As mentioned before, the blue channel in 2R has already blown out.

I am using 90% but you should play around with values here and see the effect on your own image.

That's it.

Below is the finished image. The only additional steps I have performed are to add a little Vivid Light to some select areas and also crop.

Note : The sample points placed with the Color Sampler Tool can be removed by 'right clicking' on the point and selecting delete.

Comparison image of the original and the finished images.

Pretty much that is it. I hope you find it beneficial.

Remember, do NOT save over your original file. Use 'Save As'.

There are hundreds of ways to post process. This is just one technique and I find it works well for many images.

Try it out and have fun. Be sure to try different values in the steps as this will provide you with a wealth of 'self-learned' views of how the values affect the outcome.

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