Gradient Experiments File

Remember that my intent with this book is not to show you the fastest, coolest way to edit photos, but to expose the tools and features in a way that helps you build a stronger foundation for your own work. Building and using these files is a way for you to push beyond what I’ve shown in the previous pages. If you have favorite techniques, plug-ins, or other tools I haven’t described, try them out with these files or build something new.

Each individual experiment file should be built in its own document. I prefer to use a document of 2000 px by 2000 px in 16-bit RGB, with a resolution of 300 px/inch, and either a white or transparent background.

Basic Color Bars

The first file is something I’ve used for years to see how blending modes behave over basic colors and luminosity values. Ensure that your working space is set up for your normal workflow, including such settings as gamma, color profiles, and so on. If you haven’t changed any of this before, it’s likely you don’t have to do anything more, but you can learn about the basics on the following site: helpx.adobe.com. Search for “Color settings Photoshop” and browse the results.

In your new experiment document, select the Gradient tool and then open the Gradients panel (Window > Gradients). Create a new preset group by clicking the Create New Group button at the bottom of the panel (it looks like a folder) and name the group Utility Grads.

Press D to load the default foreground and background colors (black and white, respectively), then from the Gradients panel open the Basics folder and select the Foreground To Background gradient—this will now of course be black to white. If you have a layer active in the Layers panel, clicking a gradient preset will either add a new Gradient Adjustment layer if the layer has content, or convert a blank layer to a Gradient Adjustment. Name the layer B-W 0% Smooth.

Double-click the icon on the Gradient Map layer to open the Gradient Fill dialog box, and set the Angle to 0º. Then click the Gradient swatch to open the Gradient Editor dialog box. Foreground To Background should already be loaded in the Name field.

In the editor area below the presets, find the Smoothness setting and enter 0 (zero). Smoothness interpolates luminosity values to look more uniform to your eye using a Gaussian distribution; setting the value to zero gives a linear transition between color stops. This will be important when using the Posterize adjustment later on.

Give your modified gradient a new name such as B-W 0% Smooth, and then click New to save it (see Tip). Drag the new preset to the Utility Grads group. As you create new utility gradients (such as the black-white-black gradient we created in the “Gradient Map Luminosity Selection” section of the “Selections & Masking” chapter in Part II), place them here for easy use and organization. Click OK in the Gradient Editor and Gradient Fill dialog boxes to close them.

Back in your document, create a blank layer to work on and add a new guide layout (View > New Guide Layout) with one column and eight rows, ensuring that Gutter and all other numerical settings are blank or 0.

Switch to the Rectangular Marquee tool, then create a selection from the top horizontal row. If you have not previously done so, ensure snapping is on (View > Snap). Click the foreground color swatch in the Tools panel and choose RGB red (RGB: 255, 0, 0). Fill the selection area on your blank layer with the red foreground color by tapping Option+Delete/Alt+Backspace.

Skip a row, then repeat the process for green (RGB: 0, 255, 0) on row 3 and blue (RGB: 0, 0, 255) on row 5.

For row 7, you need to create a color spectrum. In the Gradient Editor, make a new gradient preset with the settings shown in the following table. In addition, set Brightness and Saturation to 100% and Smoothness to 0%. You can start from any preset you like so long as it uses 100% Opacity; it’s probably easiest to choose a simple preset so you can add each stop individually.

This new gradient gives you a spectrum that will repeat if you use it with the Radial gradient, and gives a full account of the primary and secondary RGB colors. Save your new preset (I called mine Spectrum - RyGcBmR), and use the Gradient tool to drag from left to right across row 7, the next-to-last row on your blank layer.

Name the layer with your color bars Blend, and then duplicate it naming the duplicate Reference. Use the Move tool to drag the Reference layer downward (hold Shift to constrain the movement) until it snaps to fill the even-numbered rows in Blend. Click the Lock All button with the Reference layer active to prevent it from being changed. You’ll use this to compare the results of experimenting on the Blend layer so differences are easier to see.

Your layer stack should now look like this.

Turn off the visibility of the Blend and Reference layers for now, and add a blank layer between the B-W 0% Smooth layer (the gradient) and Blend layer. Switch to the Gradient tool and load the B-W 0% Smooth preset. Hold the M key to temporarily load the Marquee tool, then drag to select row 7. Release M, and drag from the bottom edge of the row 7 to the top edge so the selection gets a uniform black-to-white gradient. Repeat for the row 8. Here’s what the newly created gradient layer should look like.

The reason for this is because the last two rows are spectra from left to right, so a horizontal gradient won’t evenly interact with every color when we start changing blending modes. Having the black-to-white gradient vertical here ensures that each of the colors gets to blend with every level of gray.

To use this file as an experimental workbench, make the Reference and Blend layers visible again and change the blending mode of the latter. Watch how the colors behave based on how they blend with the gray layers below. You can also clip adjustment layers to the Blend layer which gives you control over the brightness, saturation, and hue of the Blend layer colors depending on which adjustment you choose. Because the adjustment layer itself does not apply a blending mode to the Blend layer, you’ll still have to choose a blending mode and/or change the opacity and fill in order to see a blended effect.

Although this particular set up doesn’t seem too exciting, it’s kind of like a “Hello, World!” programming project meant only to demonstrate that something works, leaving the how to future efforts. It allows you to see how the fundamental RGB colors behave when blended with different values of gray. One fun variation is to place some kind of color control layer between the Blend layer and the black-and-white gradient base layer. Try a Solid Color Fill layer set to Color blending, a Color Lookup adjustment layer, or even a Gradient Map layer.

More complex and useful project files can be built from these principles. Before moving on, though, take a look through the various blending modes, including the Special 8 that respond differently to the Fill slider (the Special 8 blending modes respond differently to the Fill slider than the Opacity slider. Read about them in the “Blending Modes” chapter of Part IV, “References”). As you see changes (or no change), try to describe to yourself why the result makes sense. For example, the previous image is the result of the Lighter Color blending mode.

Remembering that Photoshop assigns a weighting value to luminosity that approximates human visual perception, then it should be clear that there is some point along a black-to-white gradient where the gray value is brighter than the color. The point where the solid horizontal color bars stop is exactly where the gray value and the luminosity of the color are identical. The spectrum along the bottom shows the same effect for every RGB color at full brightness and saturation.

You can test the idea using a Curves adjustment layer clipped to the Blend layer.

Changing the RGB curve changes the relative brightness. Check out the result of a typical contrast S curve, such as the Increase Contrast (RGB) preset in the Curves Properties panel. What changed and what is the same?

Did you notice that the “pure” primary and secondary colors did not change at all? The intermediate, mixed colors did change. This result tells you that in order to adjust contrast in an image, some colors have to change. If, instead, you return the curve to its default setting and then choose the Blue channel and drag its right-side control down to the bottom of the graph, you’ll see that the blue bar does shrink until it’s gone, and the blue region of the spectrum turns black.

You can also reset the Curve and then explore how self-blends work by using blending modes on the Curves layer while leaving the Blend layer set to Lighter Color. Use Multiply for the Curves layer.

Notice the depression in the intermediate areas? Again, the color bars haven’t moved. Once you’ve built this experiment file, see if you can approximate some of the blending mode results with various combinations of adjustment layers.

You can also try adding images or other gradients between the various layers. Use an Invert adjustment layer, also clipped to the Blend layer. Just play and see what you can discover, but always think about the results you see and ask yourself “why?”

Want to explore the difference between Fill and Opacity? Set the Blend layer to Hard Mix and turn off visibility of the adjustment layers. I have some thoughts on why these behaviors are different in the “Blending Modes” chapter in Part IV, “Reference”.

Let’s move on to using the experiment file to create a preset. Set all blending modes back to Normal, all opacity and blending values to 100%, ensure no selections are active, and turn off any adjustment layers. Add a Black & White adjustment layer above the Blend layer and set its blending mode to Luminosity. This is the default black-and-white conversion that Photoshop thinks you want to start with. What’s wrong?

The default conversion results in red and blue getting a little lighter, and green getting darker. In other words, this is not a direct, neutral conversion of luminosity values. Using this setup, start by adjusting the Reds, Greens, and Blues sliders so those colors match the Reference layer. Then go back and adjust the secondary sliders. If you need more precision than dragging the controls provides, hold Option/Alt and then drag on the slider name, which slows down the movement of the control.

Once you have achieved a true neutral setting, save the preset for easy recall later (click the panel options menu in the upper-right corner of the Properties panel and choose Save Black & White Preset). I use this preset as a starting point when applying a B&W adjustment layer for detailed contrast work, as in the B&W Control Freak technique from the “Color & Value” chapter of Part II, “Techniques.”

How about an experiment that tells us something about how the Opacity setting works with color?

Turn off the Blend layer, and unlock the Reference layer. At the very top of the layer stack place a Posterize adjustment layer, leaving the default value setting of 4.

The solid color bars have not changed, but look at the gradients. The black-white gradient now has the expected four solid bands, but the spectrum is more complex. What’s going on?

Posterize splits each channel into the specific number of levels, evenly distributed between black and white. That means each channel gets four levels in this case, which you can verify by looking at each channel individually. The reason there are not exactly 12 bars in the spectrum is because of overlap. In particular, pay attention to the Red channel being split because we created the spectrum such that RGB red occurs at both edges of the document. However, each of the channels has the same gray values, and the same amount of gray (you can measure the width and brightness of each gray bar on each channel if you like).

Back in the RGB Composite channel, slowly lower the Opacity setting of the Reference layer while watching the spectrum. At about 75%, there should be a distinct change in pattern, and the edges of the solid bars may change slightly. By 70%, the solid bars obviously are being affected, and additional banding shows up in the spectrum.

Remember that the Posterize adjustment is affecting the result of the blend, not just the content of the Reference layer. The angles that show up in the spectrum are due to the way the compositing equation handles the alpha component, and represent the dividing point between the luminosity values that Posterize has used for each channel. If that word salad doesn’t mean much to you, don’t worry about it. Just pay attention to the regular pattern, which means the opacity value is smooth across the entire range of colors.

RGB Triangle

Of course, we are not limited to this rather simple design. Because there are three color channels, we can also build a triangle spectrum that shows a more logical mix of colors and allows us to explore interactions using patterns. This one is a little trickier and requires some precision while creating it.

To create the equilateral triangle, start with another square document (this time with a transparent background), and create a new guide layout of six columns and five rows, with zero gutter. Ensure that View > Snap is selected. With the Rectangular Marquee tool, drag out a selection as shown in this diagram.

With the selection still active, choose Select > Transform Selection. When the transform options appear, select Toggle Reference Point and drag the reference point from the center to the lower left of the selection. Moving the reference allows the selection to rotate from the corner.

In the options bar, enter −60 for the rotation angle. With the transform still active, chose View > Rulers and drag a guide down from the top of your document to the corner indicated here. Leaving the transform active allows the guide to snap to the corner. Press Return/Enter a couple of times, then Command+D (macOS)/Ctrl+D (Windows) to deselect.

Use the Polygonal Lasso tool to connect the corners you just used, then fill with black and deselect. We’re going to fill on the channels directly, and Photoshop will not add pixels to a blank channel. The black fill is there to “catch” the gradient we’ll apply shortly.

We have one more trick, which is finding the midpoints of the triangle’s sides. Again, drag a rectangular marquee of any width from the top of the triangle to the bottom, then drag a guide down until it snaps to the middle of the selected region—that is the half-way point of the height of the triangle, and one of the guides we previously created should intersect with it precisely on the edge of the triangle. Deselect the marquee.

And now you know a stupid Photoshop trick: how to create an equilateral triangle. That’s an accomplishment!

Okay, remember how I said to create a preset of the 0% smooth black-white gradient? Select the Gradient tool and load that preset up. Open the Channels panel, and select the Red channel. Drag from the apex of the triangle to the center point of its base. It should be white on the top, black on the bottom.

Repeat for the other two channels: Drag from the lower-right vertex to the left side’s center point for Green, and from the lower-left vertex to the right side’s center point for Blue. You may hide the guides now if you like. Click back on the RGB composite channel, then rename the triangle layer to Base. Your final triangle will show saturated channel colors in its angles and close to 35% gray in the exact center.

Add a Curves adjustment layer above that and set the Curves blending mode to Hard Mix.

Cool, huh?

Now tweak the curve and watch the pattern change (try the Solarize preset we created in the “Helper Layers” chapter of Part II, “Techniques”). Remember that setting a blending mode on an adjustment layer is effectively a self-blend of everything below the adjustment (or what the adjustment layer is clipped to).

Variations you can try with this setup:

• Duplicate the base triangle and use Cmd/Ctrl+I to invert the colors.

• Duplicate then rotate the triangle to see how different colors interact with various blending modes as well as Opacity and Fill settings.

• Add adjustment layers between the triangles or clipped to the top one.

• Use a Posterize adjustment in various places (keep the levels settings fairly low).

• Use this to explore color interactions, generate palettes of color chips, and so on.

Hue Wheel

Another favorite of mine that probably looks more familiar is a hue circle. This takes advantage of the spectrum gradient we created. In another new document sized 2000 px by 2000 px, create a guide layout of two columns and two rows, so that you get an intersecting guide right in the middle of your canvas. Switch to the Elliptical Marquee tool, ensure snapping is on, then hold Option/Alt+Shift while you drag out from the center guide intersection so that most of the square canvas is taken up with the selection.

Select the Gradient tool, load the Spectrum - RyGcBmR preset we created earlier, and select Angle Gradient. On a blank layer, drag from the center to either the top or right of the selection area. The direction in which you drag places red along that axis. In HSB color space, RGB Red is considered 0°, while green is 120° and blue is 240°. For this version, I chose red to be at the top for consistency with the RGB triangle.

Name your new layer Hue Wheel.

With the selection still active, add a blank layer above your hue wheel, then use the B-W 0% Smooth preset with the radial fill gradient (select the Reverse option) and drag from the center to the edge of the selection. This should give you a gradient from white in the center to black at the circumference. Name this layer Luminosity.

Create another blank layer, then edit the gradient to replace the white color stop with fully saturated red (Hue: 0, Saturation: 100, Brightness: 100). Drag again from the center to the circumference, creating a gradient with red in the center and black at the edge. Name this layer Saturation. Here’s the layer stack so far.

Turn off the Saturation layer, and set the Luminosity layer blending mode to Luminosity.

With your fresh, new experiment file ready to go, group the Luminosity and Saturation layers, then start adding adjustment layers and blending mode changes as before. This particular version allows for incremental rotations so you can align virtually any combination of colors. Adding saturation and luminosity layers enables you to see new patterns based on those characteristics in addition to opacity, fill, blending, and so forth.

Honestly, this one is also just a lot of fun to play with. The layer names are just to keep track of the original settings, but please do try all the different blending modes! Duplicate the Hue Wheel layer and rotate it, add some Posterize and other adjustment layers, create flat copies and apply filters—go nuts! Part of the value of these exercises is just to have fun and see what happens. Sometimes the results will be quite boring, but other times they may spark a new idea or give you a creative boost.

Solving Problems

I tinker with these and many more experiments all the time, building little files to investigate certain questions. The methodology here is similar to any scientific endeavor in that I take time to think about what I want to explore, and ask myself questions about how best to reduce the variables. The experiments themselves are not meant to be pretty, but they are meant to let me see things in an unambiguous way. Sometimes that means making multiple experiments. Although the projects I’ve talked about here focus on the RGB display spectrum, I also dive into virtually everything I can find to play with in Photoshop, including filters, plug-ins, tools, and any other element that is exposed in the user interface.

Sometimes these experiments help me reverse engineer certain techniques, such as simulating classical realism style painting. Other times they show me the limits of some function or technique, which both sets a boundary and poses new questions: What if I want to go further than the technique allows? The general process is to think about the challenge ahead and then to break it into smaller tasks. Often times, the value of an experiment—including a failed one—is how it helps shape your thinking about a problem, or expands your vocabulary regarding other situations.

We can obviously go far beyond tinkering with color and brightness, and use various filters. A classic example is using Difference blending mode with a slightly altered version of some layer content to grab the differences as a selection, as we did with in the “Hue/Saturation Selection” section of the “Selections & Masking” chapter in Part II. Instead of altering hue, what if we slightly blur a layer? The result is that high-contrast areas are now low-contrast, so we end up with a display of high-contrast edges that can be selected and used as a mask.

That mask is a great starting point for selective sharpening.

Moving deeper into filters, let’s say you want to describe the distortion effects from using the Path Blur feature in Blur Gallery. Applying a path blur to a photo is a great place to start, but how do you know if you like it? How does the blur change as the paths are changed? What would you use to show the changes, and better yet, how would you teach yourself better control over those changes?

First, we know we want something that doesn’t resemble our own art work so we can evaluate the effect and controls on their own without being influenced by whether we like the result. We also know we want to reduce the amount of variables to only the essential. The variables we typically have to work with are color and brightness, so what minimizes both? A layer filled with 50% gray meets that description, right?

But performing a task that moves pixels around is boring and pointless if you can’t see those pixels. We can add some visible pixels with the Noise filter (Filter > Noise > Add Noise). A modest amount will do, so let’s fill the gray layer with 10% monochromatic and Gaussian distribution.

Next, we can apply some blur (Filter > Blur Gallery > Path Blur).

Now we have a baseline for seeing the exact effect, and we can build from there. Changing the path lets us see the scope of the effect and how certain controls behave. You now have another entry into your vocabulary—you understand something more about the Path Blur feature. You just discovered a new hidden power, but that power is yours. It does not belong to Photoshop.

The experiment is useless without context, though. How do you fold this new power into your work? Would it be good for building textures? Can you control it well enough to imply complex motion?

Now What?

We’re going to apply general problem-solving skills in the next few projects, building on the material provided in Part II, “Techniques.” The purpose of going through experiments at this point is to provide you with a way to address challenges you will face in your editing and retouching, by giving you a way to reset your mind. As you identify the tasks at hand, you are likely to discover that the instructions for a given technique don’t exactly solve the issue. You cannot simply type in values for certain dialog boxes or exactly follow provided steps when you’re dealing with images that are vastly different than the examples provided.

Working on experiment files when you’re not under a deadline or don’t have an important project in front of you allows your familiarity with the features, techniques, and tools to grow. You’ll recognize patterns and behaviors more quickly. You will start to see new possibilities simply because your mind is making connections. Experiments give us more points of reference, and more points mean more pathways to travel.

And sometimes we just need a break. Building experiments to solve problems is great, but we do need more. Build experiments to play, to kill time; the things you discover will leave little seeds in your imagination, and when the time is right those seeds will begin to sprout.

In the projects that follow, I will not be providing details on every single step because the point is to share how I think about approaching the images. All of the projects rely on techniques previously described in the book, but they also include additional tools and methods I have not talked about earlier. The reason for this is to show that the material provided is not meant to stand alone and solve all of your imaging problems; they were always meant to expand your Photoshop vocabulary, to empower you as the artist. That means it is on you to mix this new knowledge with whatever else you can find, what you already know, and what you will learn when you put this book down.

Variations

There are lots of variations available with this technique. Using the Mixer Brush on the low-frequency layer tends to change all the elements of color, including moving brightness around. This can cause unwanted changes in the shape of facial features. You can correct this with subsequent use of dodge and burn, or you can avoid some of it by separating out the color and luminosity layers. If you want to try this out, you can isolate Color and Luminosity layers as described in the “Helper Layers” chapter in Part II, “Techniques.” You will want to treat the Luminosity layer with dodge and burn techniques rather than the Mixer Brush or blurring tools. Just be warned that this approach takes a lot more attention to detail and patience, because you are working on three different layers.

Another option is to try different kinds of blur. A popular method that seeks to preserve edges uses the Median Blur filter. This is really great for dealing with architectural and textile photos where you need to move large blocks of color around within the bounded areas.

There is something to consider when choosing your blur size, too. Different types of textures or detail may not be completely isolated from the color layer, so you should get in the habit of checking out the results of your blurred color layer. If some of the detail is left behind because the edge is larger than the radius you set for the blur, you risk damaging that texture by blending or giving it additional blur. On the other end, if you use too large of a blur radius, you don’t have much wiggle room when trying to correct smaller defects. And at some point the blur is so large that it will not line up properly with the detail layer.

That’s why I suggest you get comfortable with the idea of using multiple frequency separation passes for different textures and amounts of detail. This will be more common when dealing with images where you have closeups of both skin and fabric, or multiple textiles that need to be retouched.