Contrast technique with High Pass

After speaking many times on contrast using the filter Unsharpen mask of Photoshop, like in the tutorial Unsharp mask, the final touch with Photoshop and Save the saveable: workflow with intermediate, blur and Unsharp mask and Unsharp mask with Red channel’s technique, I’m back on the topic presenting a clever technique of contrast to use when Unsharp mask carries too obvious and too indiscriminating pixel.

In this case, I discuss a photograph taken in the aquarium of Sentosa Island in Singapore, where bright conditions is scarce.
I applied an automatic correction Automatic Layer to the original photograph, that restored some light details of white that was taken in the dark. But this tutorial does not talk about automatic corrections, you can read more on the tutorial Automatic corrections of Photoshop. The technique of contrast with High Pass is rather simple, but the results are really amazing. I invite you to post your comments on the forum into the About Photoshop Tutorial area at this link.

At first sight, the image, after the application of the automatic correction, is presented eased from a blur diffusion, even if the grain given from the bright conditions is on the verge to be visible. Applying the Unsharp mask we have surely increase of detail, but also an accentuation of the grain that would ruin the result. With this contrast technique of High Pass, the result will be great on the edges and invisible in the critical areas.

Firstly, it is necessary to create a copy of the layer that we want to contrast. In this case is Background, but there is no difference with individual layers. To duplicate a layer quickly (farewell also for the Background), drag the layer with a normal drag-and-drop on the “new layer” icon to the base of the palette layer, and we will have a copy immediately.
We apply the filter High Pass from the menu Filter> Other to the new layer created.

The image loses saturation and seem to flatten itself, but in reality it is elaborating the image with the goal to identify the tone passages. With the regulation of the ray of pixel we establish the depth of detail we want to obtain. You will see that small radius movements create considerable effects. I personally prefer radius that shows the details in clear manner, but not excessive, because the next step is a strong blending of pixel.

So, once establish the appropriate radius, we put the layer in Overlay Blending Modes. In this way the layer is molded on the background emphasizing the bright edges, and do not change any color cause the Filter> Other> High Pass had previously excluded. Another plus of this technique is that the original pixel does not get modified, as the visual effect is given from the overlapping in Overlay Blending modes, in fact. If the effect was too much, the master opacity can be lowered to the superior layer.

The final result shows good detail in the bright areas and leaves the granulose areas unchanged, even if lights was critical.

SOURCE

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