Fine Art workflow (Beaver Pond Reflections)

in Photoshop -- Part III

Article and Photography by Ron Bigelow

www.ronbigelow.com

Photoshop CS or Photoshop CS2 Used in this Tutorial

Now that the tonal and color corrections are finished, the next step is sharpening. A question that often comes up is, "When should sharpening be carried out?" The answer actually depends on what type of sharpening is being performed. A two step sharpening approach was used with this image. One sharpening layer was created after the tonal and color corrections were completed. Another sharpening layer was created just before the image was printed. The first sharpening step was designed to sharpen for the image content. This sharpening step was fairly mild and produced a gentle sharpening. This first sharpening step should be performed after all global, tonal and color corrections (major corrections that affect the entire image) have been completed but before any local, tonal and color corrections (i.e., fine tuning of tone and color that is restricted to specific areas of the image). There is a reason for this. Sharpening is actually an increase in local contrast (i.e., the contrast along edges). Changes in tonality modify contrast (changes in color can also alter tonality and thus contrast). Therefore, large changes in tone can alter the contrast that defines the sharpening. Thus, the sharpening can be affected (usually degraded) by large tonal and color edits. One the other hand, performing a mild sharpening after the major edits creates a clearer image that helps the photographer make better, final, local editing decisions than if the image is soft. The second sharpening step was designed to sharpen the image for the specific output device (in this case an inkjet printer). This sharpening should be performed as the last step just before printing.

This image is a bit unique. All of the tonal and color editing affected such large areas of the image that it was decided to treat all of the edits as if they were global. Thus, the first sharpening step was not performed until all of the tonal and color editing was completed. Then, the image was interpolated and the second sharpening step was carried out.

Edge Mask

The goal of the first sharpening step was to sharpen only the major detail. The finer detail had to be left alone. Thus, an edge mask was used. The edge mask identifies the edges of the major detail in the image and will only allow the sharpening to be applied to those edges. The less significant detail will be masked. To create an edge mask, the three channels had to be examined to determine which ones had the best detail. Figures 1 -- 3 show the channels for this image. An examination of these channels indicates that the red channel has the best detail in the grass, and the blue channel has the best detail in the mountain reflections. This information will be used in creating the edge mask.

Figure 1: Red Channel
Figure 2: Green Channel
Figure 3: Blue Channel
Figure 4: Layers Palette after Sharpen Content and Mono Layer Added
To create the edge mask, the top layer in the Layers palette was selected. A new layer was then created (click the Create a new layer icon at the bottom of the Layers palette) and the other layers effects were merged into the new layer (hold down the Alt key (Option key on a Mac); while holding down the left mouse button, select Layer/Merge Visible). This layer was renamed the Mono layer (short for monochromatic). This layer was immediately duplicated (drag the layer to the Create a new layer icon at the bottom of the Layers palette). The duplicated layer was renamed the Sharpen Content layer. Lastly, the Sharpen Content layer was hidden by clicking the eye icon on the layer. The Mono layer was then reselected. The current state of the Layers palette is shown in Figure 4.
Figure 5: Channel Mixer

It was now necessary to turn the Mono layer into a black and white layer with the most detail possible. The best tool for this was the Channel Mixer. The Channel Mixer allowed the photographer to choose how much detail was pulled out of each channel. This allowed the photographer to fine tune the Mono layer to contain the maximum amount of detail.

With the Mono layer selected, the Channel Mixer was launched (choose Image/Adjustments/Channel Mixer). The Channel Mixer is shown in Figure 5. Since a black and white layer was to be created, the Monochromatic option was checked. Now, the goal in this image was to pull out as much detail as possible in the grass. Since it was not desired to sharpen the water (since that would have given the water and the reflection an unnatural look), it was not important how much detail was created in the water. Since the red channel had the most detail in the grass, it was used the heaviest in the channel mixer (140%). It was found that adding a small amount of the blue channel (26%) enhanced the contrast and, therefore, the detail in the grass. The green channel was actually decreased (-50%). Clicking OK converted the Mono layer to black and white. Figure 6 shows the Mono layer after the Channel Mixer was used. Figure 7 shows a close up of the grass.

Figure 6: Mono Layer after Channel Mixer
Figure 7: Close up of Mono Layer after Channel Mixer
It was now necessary to identify the edges in the Mono layer. This was done by using the Find Edges filter (choose Filter/Stylize/Find Edges). Figure 8 shows the layer after the Find Edges Filter had been run. Figure 9 shows a close up of the grass. At this time, the edges are shown in black.
Figure 8: Mono Layer after Find Edges
Figure 9: Close up of Mono Layer after Find Edges
Figure 10: Levels
It was necessary to increase the contrast of the layer to make the edges stand out even more. This was done by using Levels (choose Image/Adjustments/Levels). The Shadow slider was moved to the right, and the Highlight slider was moved to the left (see Figure 10). Figure 11 shows the layer after Levels had been run. Figure 9 shows a close up of the grass.
Figure 11: Mono Layer after Levels
Figure 12: Close up of Mono Layer after Levels
Figure 13: Gaussian Blur
It was necessary that the image be blurred to soften the mask so that the light to dark transitions were not so abrupt. This was done by using the Gaussian Blur tool (see Figure 13). The Radius setting is determined by the detail of the image. Usually, I find a setting of 3 or a bit larger to work well. In this image, the fine detail required a very small Radius of about 1.0. Figure 14 shows the layer after Gaussian Blur had been run. Figure 15 shows a close up of the grass (there is not much difference from Figure 12 since the blurring was very gentle due to the fine detail in the grass).
Figure 14: Mono Layer after Gaussian Blur
Figure 15: Close up of Mono Layer after Gaussian Blur
Figure 16: Levels
Since the blurring step reduced the contrast a bit, Levels was run again (see Figure 16) to increase the contrast. This Levels step was gentler than the first one. Figure 17 shows the layer after Levels had been run. Figure 18 shows a close up of the grass.
Figure 17: Mono Layer after Levels
Figure 18: Close up of Mono Layer after Levels
This layer was created in order to generate a mask that would allow sharpening of only the edges. However, at this point, the edges of the Mono layer were still defined in black. A resulting mask would block out the edges -- the exact opposite of what was desired. So, the image was inverted (choose Image/Adjustments/Invert). Figure 19 shows the layer after Invert had been run. Figure 20 shows a close up of the grass.
Figure 19: Mono Layer after Invert
Figure 20: Close up of Mono Layer after Invert

It was now time to turn the Mono layer into a selection and then an edge mask. The Channels palette was selected. Within the Channels palette, the RGB channel was selected. The Load Channel as Selection icon at the bottom of the palette was clicked. This turned the Mono Layer into a selection.

Figure 21: Image with Selection

Moving back to the Layers palette, the Sharpen Content layer was selected and the eye icon was clicked to unhide the layer. Figure 21 shows the image with the selection.

There was one problem with this selection, as can be seen in Figure 21, parts of the water were selected. This was not acceptable, as the water was not to be sharpened. To solve this problem, the image was moved into Quick Mask Mode (choose Edit in Quick Mask Mode on the Tools palette). The Brush Tool was selected from the Tools palette and the water was painted over with a black brush. However, care was taken not to brush over the grass that was floating in the water as that grass needed to be sharpened. Figure 22 shows the image in Quick Mask Mode after the editing.

Figure 22: Image in Quick Mask Mode after Editing
Figure 23: Image with Selection after Editing
Figure 23 shows the image with the selection after the editing on the mask had been completed. As can be seen in the figure, the water was no longer selected.
Figure 24: Layers Palette
The selection was saved as the Sharpen Content selection (choose Select/Save Selection and choose New Channel). The Mono layer was deleted as it was no longer needed (drag the layer to the Delete layer icon at the bottom of the Layers palette). Lastly, the Blend mode for the Sharpen Content layer was set to Luminosity. Figure 24 shows the Layers palette at this point in time.
Figure 25: Layer Style Menu
It was desired that this sharpening layer not sharpen the shadows (this would likely sharpen noise) or the highlights. An easy way to control this was with the Blend-If control (choose Layer/Layer Style/Blending Options). The Blend-If control is shown on the Layer Styles menu in Figure 25 (for more information, see Sharpening and Fine Tuning). Adjusting the sliders on the This Layer control determines which tonal values will be affected by this layer and receive sharpening. Figure 25 shows the values chosen for this image. The sharpening of the shadows starts to decrease at a tonal value of 41. Below a tonal value of 12, no sharpening is done at all. On the highlight side, the sharpening starts to decrease at a tonal value of 234; above a tonal value of 249, no sharpening is done.

Sharpen

Figure 26: Smart Sharpen

It was now time to apply a mild sharpening to the Sharpen Content layer. With the monitor set to 100%, the Sharpen Content layer was selected, and Smart Sharpen was launched (choose Filter/Sharpen/Smart Sharpen). On the dialog box, Remove was set to Lens Blur, and the more accurate option was checked (see Figure 26).

When sharpening, perhaps the most important key to getting the sharpening right is to find the correct Radius. Too large of a Radius will destroy detail, and too small of a Radius will sharpen unwanted detail (e.g. noise). Thus, the Radius was set first. At this point, it was not desired to actually sharpen the image. Rather, the intention was to find the correct Radius. To start off, the amount was set at a fairly high value (300%). The high amount produced a greatly exaggerated sharpening. This was okay for now because it made it easy to see what impact different Radius settings had on the image detail. The Radius slider was moved around while the image was observed. The Radius was moved to the point where the image detail began to degrade; then, the Radius setting was backed down a bit. This resulted in a Radius of 1.6. This is a fairly small Radius, but it was necessary due to the fine detail in the grass.

A 100% view of the unsharpened reed detail is shown in Figure 27. Figure 28 shows a 100% view of what the image looks like with Smart Sharpen set at a Radius of 1.6 and an amount of 300%.
Figure 27: Detail in Reeds without Sharpening
Figure 28: Detail in Reeds with a Radius of 1.6 and an Amount of 300%
The Radius was noted, and the dialog box was closed without sharpening the image. The reason that the image was not sharpened at this point is that the edge mask needed to be in place before the amount setting was determined.
Figure 29: Layers Palette

With the Sharpen Content layer still selected, the Sharpen Content selection was loaded (choose Selection/load Selection and New Selection). The selection was then turned into a mask (choose Layer/Layer Mask/Reveal Selection). The Opacity was set to 50%. This was done so that the sharpening could be adjusted either up or down, at a later time, if so desired. The Layers palette is shown in Figure 29. Last, the monitor was set to 50% view.

Figure 30: Smart Sharpen
Smart Sharpen was launched again (see Figure 30). At this time, it must be remembered that it was desired to produce a very gentle sharpening. It was found that an amount setting of 170% produced the desired effect. A 50% view of the unsharpened reed detail is shown in Figure 31. Figure 32 shows a 50% view of the sharpened image with a Radius of 1.6, an amount of 170%, and an Opacity of 50%.
Figure 31: 50% View of Detail in Reeds without Sharpening
Figure 32: 50% View of Detail in Reeds with a Radius of 1.6, an Amount of 170%, and an Opacity of 50%
A comparison of Figures 31 and 32 clearly shows that the sharpening was very minor (if you do not have a good monitor, you might not be able to see the difference). In many other images, the sharpening would be made somewhat stronger at this step. However, some test prints made with this image showed that the fine detail was easily oversharpened. So, this first sharpening step was made very gentle.

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