PPW Contrast Boost – two new actions and their place in the workflow
Yet another contrast phase
The shortest possible summary of the Picture Postcard Workflow is: Color – Contrast – Color Again. You find exactly this in the Modern Color Workflow Book, one of the first paragraphs of chapter 1. It’s so cut down that no one knows what to do from these three words only. Of course it helps those already familiar with the workflow to keep the overall flow in mind. The question is, why do we process color twice? The answer: at the beginning, we correct color casts. At the end, we boost color.
Figure 1 shows the “Final Version” of the PPW steps. It seems like there are not three but five phases, right? One could argue that the listed Finalize steps are not about “Contrast” or “Color”, but Sharpen is an essential step in every image enhancement workflow, and it is – as common wisdom prescribes – always executed near the end.
So, contrary to what our short summary may suggest, contrast also comes in two phases. There is the contrast as in the above three-word summary, like the meat in the color sandwich. And there is contrast again when an image is sharpened right at the end of the processing. After the Color Boost phase, contrast is boosted as well. That’s the second contrast step. We call it local contrast. When local is so local that it’s hardly discernable (think 1-3 pixels), it’s conventional sharpening. When local is a bit larger, say 30-50 pixels, we tend to give it a fantasy name. Dan Margulis calls it: Hiraloam, which is short for High Radius Low Amount. In ACR and Lightroom it’s named Clarity. Another popular name is Shaping. The Italian website knowhowtransfer.com has a tradition of commercial plugins for local contrast enhancing: over time, they were called Alce, Next and Shape. See figure 2 (hope they don’t mind this copy from their website…).
Figure 1. The PPW steps
Figure 2. The three contrast-enhancing plugins of knowhowtransfer.com in one image
So in the PPW we have two contrast enhancing phases:
- one dealing with global contrast: channel blending, curving, the Hammers and the likes, and the Darken Sky scripts;
- and the other dealing with local contrast: shaping and sharpening.
The better summary would thus be: Color – Global Contrast – Color Again – Local Contrast.
Global or local?
The classification of Darken Sky as a global contrast move may surprise you: it touches sky only, so isn’t that about local contrast instead? Well, no, but the confusion is understandable. Let’s settle the difference between global and local contrast.
A contrast move is local if it is determined by nearby pixels. Sharpening is the ultimate example: pixels may get darker or lighter, depending on how they relate to their close neighbors, not more than a few pixels away. Shaping is very similar, only it looks a bit further than a few pixels. The goal of sharpening is to strengthen edges; the goal of shaping is to give depth to an image, like a 3D effect.
Enhancements that do not depend on local variations are called global contrast moves. Darken Sky is indeed a good example. Sky is darkened, regardless of whether its surroundings are lighter (clouds) or darker (mountains). The same is true for a curve adjustment or a channel blend. The goal of a global move is to fix overall exposure and contrast problems.
This may sound like a strict distinction between the two categories, but in reality it’s a bit fuzzy. The Unsharp Mask (USM) filter is Photoshop’s typical local contrast enhancement tool. One of its parameters is Radius, which could be considered as the size of the neighborhood that defines the actual move. Small radius: sharpening. Large radius: shaping.
In my third article about the filter (https://geraldbakker.nl/psnumbers/sharpen-3.html) I closely examined the distinction between local and global contrast. In this article, I concluded that the farther away we look for “surrounding” pixels (in USM terminology: the larger the Radius), the closer the effect will resemble a global contrast move. Make Radius large enough (think 100 pixels or more), and an application of USM is more global than local. This is where the distinction blurs, and I believe it’s an important aspect when trying to give “shaping” a place in the Picture Postcard Workflow.
See figure 3: top left, an original image; top right, a moderately strong S-curve applied, put on a layer in Luminosity mode; bottom left, USM applied with Radius 200 and Amount 40; bottom right, idem but Radius 40. Note that an USM application with smaller Radius causes a stronger texture (i.e. local contrast). The USM with larger Radius is more similar to the result of an S-curve (i.e. global contrast).
Figure 3. Top left: an original. Top right: a strong curve applied.
Bottom left: USM with Radius 200. Bottom right: idem with Radius 40.
A wish to Shape
Back to the PPW2025. Now that we have the PPW2025 panel stable and most of its bugs solved, there is room for new functions. When I asked the colortheory group for ideas, the one response that stood out was: add a button that behaves like the Shape plugin (the one from knowhowtransfer.com). People reported problems getting it to run on the latest Photoshop versions, and author Davide Barranca acknowledged that support will not continue.
So I started a quest for the algorithm behind Shape. That brought me on two different paths.
First, I examined the result of the Shape plug-in. (Knowhowtransfer.com allows free download of an evaluation version which, if I understand well, provides full functionality but when invoked puts a watermark over the trial image.) The plug-in has a bunch of configuration parameters, so a full reverse engineering would be impossible. But at default values, the result of the action looks like a simple application of the Unsharp Mask filter with a very high radius. Certainly not the same, but a good shot in the right direction. So this is attempt one: Unsharp Mask – I chose Radius 100 and Amount 40%.
Second, I asked around and found out that a primal version of the Shape, Alce and Next plug-ins was a clever Photoshop action, sometimes called “Local Auto-Levels”, sometimes simply “Local Contrast”. This action dates back to 2007 (!) and was devised by a Jay Ryness. A short summary is provided by the author himself when he compares his action with the standard Auto-Levels: “Instead of choosing the black point and white point globally, what if it could vary across the image? If each pixel was adjusted according to the darkest and brightest values in its region, the result should be equal contrast everywhere.” Like the USM filter, this action needs a radius value to define how wide “region” is defined. But unlike USM: the lower the radius, the stronger the action. Various websites contain copies of the action, so I was able to experiment with it. Turns out: in most cases, this action has a stronger effect than a high-radius Unsharp Mask. It is quite prone to haloing, even though the action contains a safeguard against it. This can ruin images containing areas without variation like – there we go again – blue skies.
The new actions...
So… the latest PPW2025 panel offers two new actions that mimic the Shape plug-in. One, a simple application of Unsharp Mask with a very high Radius and a moderate Amount. Two, a new manifestation of the old “Local Auto-Levels” action, with a Radius that is updatable from the panel (the default is again 100). The first one is simply called Contrast Boost and for now comes in the Additional Actions panel. We named the other one Contrast Boost Extra – it has gotten its own button next to the Sharpen 2025 button.
See figure 4 for the new layout of the PPW2025 panel.
Both actions provide an extra layer that is called “Reduce sky halos”. This is a simple copy of the starting layer, filtered for blues of moderate lightness. By default, this layer is hidden. If your image contains bright blue skies, chances are that the action’s result looks better when this layer is made visible. Of course, you may prefer a different Radius value or a reduced layer opacity; adding a mask is also possible, especially if the image contains other blues that do benefit from the action.
… and their place in the workflow
Now the question is, where do these actions fit in the Picture Postcard Workflow? Should they be executed during phase 2 (Global Contrast), right with the Curves, Channel Blending and the likes? Or during phase 4 (Local Contrast), together with a sharpen?
My answer to this question is: the most logical place is phase 2. The “shaping” effect may strictly speaking be a local and not a global contrast move - but with the high radius that is the default, the effect is not unlike something like an effective channel blend followed by a strong S-curve. The Contrast Boost actions are definitely closer to the contrast enhancing moves than to the Sharpen action.
However, this is no hard rule. There may be situations where you choose differently. Let me just give a few reflections on this matter, hoping they will inspire you to experiment.
Figure 4. The PPW2025 panel version 1.3.2.
- The PPW encourages multiple applications of the workflow, and it’s a good idea to vary between different runs. So if you applied Contrast Boost the first run at the beginning, why not do it a second time near the end, right after the color steps?
- The actions are rather strong. Their effect may impact the choices you make during the color enhancement phase. Here is an example. The MMM Finetuned action starts with a selection and impacts image areas similar to this selection. So blowing up local contrast like the Contrast Boost actions can do, changes the regions that MMM Finetuned will see as similar. This may be beneficial to the final result… or not. Whatever the effect, it pays to experiment.
- Both actions allow you to change the Radius from the default of 100 to any other value. The lower you set the Radius, the more “local” the result will be, and the closer it will resemble a high-radius, low-amount sharpen. Just try to do the following: open an image and duplicate it. On the first instance, run Contrast Boost and change the USM parameters to 35 px / 25%. On the second, run Sharpen 2025 and hide all layers except Hiraloam Darken and Hiraloam Lighten. The two versions are quite close, aren’t they? So if you run any of the Contrast Boost actions and decide that your image looks better with a lower radius, it is advisable to postpone this until right before Sharpen, and (if you use the PPW Sharpen action) switch off the Hiraloam Darken and Lighten layers.
That’s it. Use the new actions to your liking, and experiment away.
Gerald Bakker, 17 May 2026
Picture Postcard Workflow
