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Retouching Skin
Tutorials and Reviews
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Retouching Skin part 1
Tutorial by edgework
This is a topic that often falls outside of the concerns of professional photographers; rather than capturing reality and presenting an honest depiction of what one finds there, this endeavor is concerned with... well, lying. At its simplest, it's an effort to help the subject look their best; at its most extreme, we are creating fantasy pure and simple, with results that are never found in the real world. Ever. No one looks like this, not even Tyra Banks. (She comes pretty close, though).
Perfectly smooth skin is a tricky retouching challenge. It's a series of complex gradients moving not only from lights to darks and from one hue to another but in multiple directions as well. It doesn't take much for the eye to fasten on imperfections and the effort to remove them often creates more problems. Until Photoshop 7, the tool of choice for skin work was the cloning tool (No purer manifestation of evil has ever been found.) It was, and remains, woefully inadequate to the task. The combined challenge of maintaining the smoothness of the gradients without losing believable skin texture made many retouchers reconsider their applications to McDonalds. With PS7 the Healing Brush made it's appearance and music and light once more filled the land of retouching.
There are three ways to approach skin retouching. The most common is to think like a plastic surgeon: you graft skin from a healthy area onto the problem spots and hope you can minimize the scars. But imperfections can also take the form of unwanted variations in dark and light areas. Rather than replacing an unwanted area, we dodge or burn the areas, lightening or darkening just enough to bring them into balance. Sometimes the problem is one of mismatched color, and we must find a way to exploit color correction techniques.
These three approaches constitute 90% of the time you will spend on a serious retouching job. None of them requires arcane techniques; they do require finesse, and, most of all, patience. There is no quick fix for skin, not if the desire is to make it look both flawless and real and to hide your own tracks. None of the whiz-bang effects that LAB produces will be found here. Most of the job entails endless repetition of the same simple moves, with results so slight you'll often wonder if you're accomplishing anything. Until you turn your retouching layer on and off. You get your whiz-bang effect at the end of the job when you compare before and after version.
One technique that has been around forever, and which lives to this day, is to create some form of smoothing layer on top of the offending skin and try to blend it into the original without making it look fake. Whether one paints tones in with an air brush, or tries some blurring moves, this approach is roundly scorned by most magazine editors and, when done too obviously, will not only get the job bounced, it will earn those responsible a place on the "Do Not Use" list. Still, the reason it remains a current technique is that, done right, it works. It is to be hoped that we will do it right.
In this section I will address the three approaches to skin work already mentioned. In Part 2, I will deconstruct a couple of jobs, discuss contrast moves, smoothing, sharpening, how to make skin glow, and other fantasies.
THE HEALING BRUSH
Adobe has described the Healing Brush as "The Cloning Tool on steroids." Somewhat true. While you can often treat it like a cloning tool, one that doesn't require precision and offers superior results, it comes with its own set of quirks, and capabilities that go beyond cloning. For any skin work, it will be one of your primary tools.
First, let's note the most peculiar quirk of the Healing brush. In theory, it retains the color and lightness of the target area, while replicating the relationship between lights and darks from the sampled area, translating the sampled texture into the target range of value and tone. It also performs a kind of magical blending between target and sample, and at the edge of the strokes, without muting detail. While this blending pretty much eliminates the "clone worms" so prevalent with the cloning tool, it can be both blessing and bane.
In these images, we see what can go wrong with the healing brush.
The pattern of fine hairs needs to be smoothed out. It would seem to be a perfect job for the healing brush, given it's blending capabilities. (A) We sample from a nearby region with texture but no hair (B). But the result (C) demonstrates the blending capability of the healing brush, precisely where we don't want it. Part of the problem is that we've made our target area too close to a much darker region, but the main problem is the brush size. The ability to suck in surrounding pixels is a direct function of the size of the brush.
Note the similar target area in (D), but with a significantly smaller brush. The result this time (E) is much more in keeping with expectations.
So¬ó
Rule 1: always keep the size of your brush in proportion to the artifacts that are being dealt with. Even if the overall area that you cover with a single move is much larger, the tendency to pull in unwanted pixels will be determined by the brush size. (On the other hand, if there is a sharp transition that you want to smooth out, replicating the "mistake" of image (A) can become a valued procedure. A few passes on either side of the transition line, pulling the regions into each other, can make for smooth transitions.)
Rule 2: Don't use the healing brush to make drastic shifts in color or value (i.e. removing a dark shadow, or a necklace.) It will make a soupy mess of the job. Prep the area first by using the Dodge/burn techniques or the color moves discussed next, to bring the target into rough balance with the surrounding area. You could even use the clone tool.
Here's an unsightly wrinkle that we're simply going to take out (A). Keep in mind, the healing brush is quite forgiving. You don't need to worry about lining up your sample with your target, you don't need to be particularly precise. (B) shows a typical stroke that I might make, and the result (C). And after four or five similar strokes we arrive at (D).
The question could be raised, "Why use the healing brush for a shadow like this? Why not a dodge/burn layer?" As I will demonstrate, I make extensive use of dodge/burn layers to lighten and darken selective areas. However, unlike the healing brush, dodging and burning requires infinite patience and subtlety. And precision. Large imperfections like this wrinkle are among the first things that I'll attack, and I do it with the healing brush because it's fast. I can be sloppy. I basically scribble over the target area; maybe I'll draw circles, maybe half-moons. It doesn't matter. The healing brush responds to all of it and after a relatively short time, the gross imperfections suddenly become much less noticeable. And much more conducive to the refined shifts that dodging and burning provide.
My initial moves always are with the healing brush. I try to attack everything I see. By definition, if I notice it, it shouldn't be there. So it's only natural that I would deal with deep wrinkles around the eyes and in the face at this point. The healing brush makes quick work of them
Here's a fairly normal pair of eyes (A); however if they were meant for a cover of, say, Elle, the instruction would be "Knock back the wrinkles some." Which means keep it real. Don't do an eye-lift that stretches the skin tight and glossy.
Now, retouching just part of the way is kind of a pain; the usual approach is to set your cloning or healing tool at a low opacity and clone some clean skin over the wrinkle. This is never particularly satisfying; there's almost always a softness and loss of detail surrounding the actual wrinkle.
What is easy, using the healing brush, is to hit the offending wrinkles head on and obliterate them altogether (B). Then cut out the originals from the layer beneath, and put them on top (C). Now you just need to set the opacity to determine how much you will knock them back. This is how they look at 40% (D). There is still some discoloration and unevenness, but it was already there. We'll deal with that in later fine tuning steps. But for deep face, neck and eye wrinkles, this will allow you to keep believability, while repairing the damage.
One last thing to keep in mind, both with the Healing Brush, and with the two techniques that follow: Start close up, at 100%. Then move back out to 50%. Avoid odd scaling values. 66.7% and 33% aren't horrible, but 71.83% would be a disaster. At 100%, there is a one-to-one ratio between screen pixels and image pixels. 50% and 25% yields results that compress the pixel information evenly, much the same as happens when you print at actual size. Odd scalings create interference artifacts from uneven interpolation of image pixels to screen pixels. At even scalings, you will see artifacts that weren't apparent at 100%, and you can trust that they are actually there. So you will want to make several passes, zooming out each time and dealing with the new problems that show up.
You won't get it perfect with the healing brush, but as you can see here, sudden transitions with their obvious edges are easy to remove. And now the imperfections that remain can be dealt with much more effectively by the next technique.
Tutorial by edgework
This is a topic that often falls outside of the concerns of professional photographers; rather than capturing reality and presenting an honest depiction of what one finds there, this endeavor is concerned with... well, lying. At its simplest, it's an effort to help the subject look their best; at its most extreme, we are creating fantasy pure and simple, with results that are never found in the real world. Ever. No one looks like this, not even Tyra Banks. (She comes pretty close, though).
Perfectly smooth skin is a tricky retouching challenge. It's a series of complex gradients moving not only from lights to darks and from one hue to another but in multiple directions as well. It doesn't take much for the eye to fasten on imperfections and the effort to remove them often creates more problems. Until Photoshop 7, the tool of choice for skin work was the cloning tool (No purer manifestation of evil has ever been found.) It was, and remains, woefully inadequate to the task. The combined challenge of maintaining the smoothness of the gradients without losing believable skin texture made many retouchers reconsider their applications to McDonalds. With PS7 the Healing Brush made it's appearance and music and light once more filled the land of retouching.
There are three ways to approach skin retouching. The most common is to think like a plastic surgeon: you graft skin from a healthy area onto the problem spots and hope you can minimize the scars. But imperfections can also take the form of unwanted variations in dark and light areas. Rather than replacing an unwanted area, we dodge or burn the areas, lightening or darkening just enough to bring them into balance. Sometimes the problem is one of mismatched color, and we must find a way to exploit color correction techniques.
These three approaches constitute 90% of the time you will spend on a serious retouching job. None of them requires arcane techniques; they do require finesse, and, most of all, patience. There is no quick fix for skin, not if the desire is to make it look both flawless and real and to hide your own tracks. None of the whiz-bang effects that LAB produces will be found here. Most of the job entails endless repetition of the same simple moves, with results so slight you'll often wonder if you're accomplishing anything. Until you turn your retouching layer on and off. You get your whiz-bang effect at the end of the job when you compare before and after version.
One technique that has been around forever, and which lives to this day, is to create some form of smoothing layer on top of the offending skin and try to blend it into the original without making it look fake. Whether one paints tones in with an air brush, or tries some blurring moves, this approach is roundly scorned by most magazine editors and, when done too obviously, will not only get the job bounced, it will earn those responsible a place on the "Do Not Use" list. Still, the reason it remains a current technique is that, done right, it works. It is to be hoped that we will do it right.
In this section I will address the three approaches to skin work already mentioned. In Part 2, I will deconstruct a couple of jobs, discuss contrast moves, smoothing, sharpening, how to make skin glow, and other fantasies.
THE HEALING BRUSH
Adobe has described the Healing Brush as "The Cloning Tool on steroids." Somewhat true. While you can often treat it like a cloning tool, one that doesn't require precision and offers superior results, it comes with its own set of quirks, and capabilities that go beyond cloning. For any skin work, it will be one of your primary tools.
First, let's note the most peculiar quirk of the Healing brush. In theory, it retains the color and lightness of the target area, while replicating the relationship between lights and darks from the sampled area, translating the sampled texture into the target range of value and tone. It also performs a kind of magical blending between target and sample, and at the edge of the strokes, without muting detail. While this blending pretty much eliminates the "clone worms" so prevalent with the cloning tool, it can be both blessing and bane.
In these images, we see what can go wrong with the healing brush.
The pattern of fine hairs needs to be smoothed out. It would seem to be a perfect job for the healing brush, given it's blending capabilities. (A) We sample from a nearby region with texture but no hair (B). But the result (C) demonstrates the blending capability of the healing brush, precisely where we don't want it. Part of the problem is that we've made our target area too close to a much darker region, but the main problem is the brush size. The ability to suck in surrounding pixels is a direct function of the size of the brush.
Note the similar target area in (D), but with a significantly smaller brush. The result this time (E) is much more in keeping with expectations.
So¬ó
Rule 1: always keep the size of your brush in proportion to the artifacts that are being dealt with. Even if the overall area that you cover with a single move is much larger, the tendency to pull in unwanted pixels will be determined by the brush size. (On the other hand, if there is a sharp transition that you want to smooth out, replicating the "mistake" of image (A) can become a valued procedure. A few passes on either side of the transition line, pulling the regions into each other, can make for smooth transitions.)
Rule 2: Don't use the healing brush to make drastic shifts in color or value (i.e. removing a dark shadow, or a necklace.) It will make a soupy mess of the job. Prep the area first by using the Dodge/burn techniques or the color moves discussed next, to bring the target into rough balance with the surrounding area. You could even use the clone tool.
Here's an unsightly wrinkle that we're simply going to take out (A). Keep in mind, the healing brush is quite forgiving. You don't need to worry about lining up your sample with your target, you don't need to be particularly precise. (B) shows a typical stroke that I might make, and the result (C). And after four or five similar strokes we arrive at (D).
The question could be raised, "Why use the healing brush for a shadow like this? Why not a dodge/burn layer?" As I will demonstrate, I make extensive use of dodge/burn layers to lighten and darken selective areas. However, unlike the healing brush, dodging and burning requires infinite patience and subtlety. And precision. Large imperfections like this wrinkle are among the first things that I'll attack, and I do it with the healing brush because it's fast. I can be sloppy. I basically scribble over the target area; maybe I'll draw circles, maybe half-moons. It doesn't matter. The healing brush responds to all of it and after a relatively short time, the gross imperfections suddenly become much less noticeable. And much more conducive to the refined shifts that dodging and burning provide.
My initial moves always are with the healing brush. I try to attack everything I see. By definition, if I notice it, it shouldn't be there. So it's only natural that I would deal with deep wrinkles around the eyes and in the face at this point. The healing brush makes quick work of them
Here's a fairly normal pair of eyes (A); however if they were meant for a cover of, say, Elle, the instruction would be "Knock back the wrinkles some." Which means keep it real. Don't do an eye-lift that stretches the skin tight and glossy.
Now, retouching just part of the way is kind of a pain; the usual approach is to set your cloning or healing tool at a low opacity and clone some clean skin over the wrinkle. This is never particularly satisfying; there's almost always a softness and loss of detail surrounding the actual wrinkle.
What is easy, using the healing brush, is to hit the offending wrinkles head on and obliterate them altogether (B). Then cut out the originals from the layer beneath, and put them on top (C). Now you just need to set the opacity to determine how much you will knock them back. This is how they look at 40% (D). There is still some discoloration and unevenness, but it was already there. We'll deal with that in later fine tuning steps. But for deep face, neck and eye wrinkles, this will allow you to keep believability, while repairing the damage.
One last thing to keep in mind, both with the Healing Brush, and with the two techniques that follow: Start close up, at 100%. Then move back out to 50%. Avoid odd scaling values. 66.7% and 33% aren't horrible, but 71.83% would be a disaster. At 100%, there is a one-to-one ratio between screen pixels and image pixels. 50% and 25% yields results that compress the pixel information evenly, much the same as happens when you print at actual size. Odd scalings create interference artifacts from uneven interpolation of image pixels to screen pixels. At even scalings, you will see artifacts that weren't apparent at 100%, and you can trust that they are actually there. So you will want to make several passes, zooming out each time and dealing with the new problems that show up.
You won't get it perfect with the healing brush, but as you can see here, sudden transitions with their obvious edges are easy to remove. And now the imperfections that remain can be dealt with much more effectively by the next technique.
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DODGING AND BURNING
The healing brush's value is the ease with which lots of gross imperfections can be brought under control without a loss of skin texture. But if you want to take that next step to flawless skin, you will need to dodge and burn¬óagain, and again and again.
With the healing brush i will try to cover as many bases as possible before moving on. Dodging and burning is never finished. Sometimes the problems that it has to address don't become obvious until other steps have been completed. A typical work flow might look something this:
Healing Brush
Contrast move
Dodge/burn
Color move
Dodge/burn
HIRALOAM
Dodge/burn
Healing Brush
Dodge/burn
Smoothing
Dodge/burn
Add glow
Dodge/burn
Sharpen
Dodge/Burn
Have lunch
Dodge/burn
You get the idea.
A quick search of any number of Photoshop forums will turn up a variety of approaches to this task. I'll be honest, I haven't tried most of them; I found the version I like and it's never let me down. If you wish to embellish or modify this technique, by all means, do so.
None, by the way, involve actually using the Dodge/Burn tools on the image pixels themselves. Don't even think about that. They all involve placing dark and light tones in a layer or layers above the image with the intention of countering unwanted variations in the lights and darks. Usually, this layer will be in Hard Light, Overlay or Soft Light mode. All three modes interact with the underlying pixels to create lighten or darken effects.
In all three modes, 50% gray has no effect at all. Hard Light and Overlay will screen tones lighter than 50% against the underlying pixels, and multiply tones that are darker. With Overlay, the effect diminishes as the underlying pixels approach white and black, concentrating the effect in the quarter tones and three-quarter tones. A layer filled with white in Overlay Mode will bleach out most of the image, but the shadow detail will be retained. Hard Light mode affects the highlight and shadow detail as well and as a result, produces a much stronger effect. To be honest, I'm not sure what Soft Light does. It's similar to Overlay in that highlights and shadows are retained, but the effect is, well, softer. The best way to see the difference is to place a layer above any image you choose, fill it alternately with white and black in each of the three modes.
Painting light or dark colors in a layer in any of these modes will result in lightening or darkening of the image. There are endless variations: filling a layer with 50% gray and using the Dodge and Burn tools on that neutral color; creating a multiply layer and a screen layer and alternating the use of each one, depending on whether you wish to dodge or burn. I like simplicity and a minimum of steps (very important with a procedure that you will repeat endlessly) so I create a transparent layer in Hard Light mode. There's no need to fill it with 50% gray; it has no effect other than to make it easy to see your stroke if you isolate the layer.
Whatever mode you use, the key is a small brush, low opacity and a pressure sensitive tablet. I set my brush to 5% opacity and my tablet pen opacity mode to pressure, and I vary the size in direct porportion to the artifacts I am modfying. It's better to build up many small strokes over an area than to try to cover everything with one or two large strokes.
The colors I choose to paint with depend on the image. Often, white and black work just fine, as the only thing we are trying to do here is alter the lightness value of discreet parts of the image. However, sometimes you will run into saturation and hue problems using this approach: merely lightening a dark area or darkening a light area can yield values equal to the surrounding pixels, but with colors that desaturated to blend. It's often a good idea to sample from the lightest highlight (that hasn't gone to white) and darkest shadow (that hasn't gone totally to black.) Setting one color to foreground and one the background, it's a simple click of the "X" key to change them around. That's the beauty of this approach: one tool (the brush) one layer, one key stroke to switch from dodging to burning and back again.
Here is where accuracy is required. The imperfections that you are targeting are small to begin with, and as you progress, they become ever more subtle. If you're not accurate, you'll simply create new artifacts, rather than eliminate those that are already there. It's hard to demonstrate dodging and burning in separate images, since each move is so slight. So here's a before and after shot, with the dodge/burn layer. I set the strokes against 50% gray so they can be seen. In practice, I usually don't bother. Filling with gray is just one more unnecessary step that I don't want to take the time to do. Don't try to count the strokes; it's too depressing. An advantage of switching dark and light colors on the same layer is that you can almost run on automatic pilot; the process of adding strokes becomes a kind of zenlike activity where you don't really notice time passing. It's a small price to pay for beauty.
COLOR IMPERFECTIONS Note the unfortunate skin blotches on this otherwise cute little baby. This image comes from a thread where a genuine whiz-bang LAB technique was discussed, and which is certainly relevant to any discussion of skin imperfections, particularly color problems. That thread is here. I highly suggest acquiring facility working in LAB, in general. As this thread shows, some valuable tools are available that you won't find in other spaces. However, this is about retouching and there's no point rehashing LAB discussions that have been dealt with in far greater depth elsewhere.
I took a more conventional approach, using selective colors and a variety of other tricks, eventually bringing me to this unsatisfactory point.
The red areas are too extensive to yield to the healing brush, and dodging won't really solve the problem. The color problem will still be there even if we get the values in sync.
Whenever I have a problem like this one, I like to treat it like a simple color correction issue. I have one area that I don't like, and another area that I'd like to match. It's a perfect problem for a set of curves to solve; the only problem is creating a decent mask through which to engineer the shift. My solution is to work backwards.
First, I set a color sampler in the middle of the triangular patch of skin just to the left of the nose, as the tone I wanted to match. Then I set a second sampler somewhere in the middle of the red blob just to the left of the first area. The red sampler read R:209, G:135, B:108. The clear sampler read R:229, G:182, B:156.
Next, set a curve adjustment layer and fill the layer mask with black. Make sure that the gradient at the bottom of the window has black on the left. now set a midpoint in each of the channels, plugging in the values as they appear in the info palette. In the red curve, with the midpoint selected, you would enter 209 for Input, 229 for Output. In the green curve use 135 for input, 182 for output, and in the blue curve use 108 for input, 156 for output.
The next step is identical in mechanics to using a dodge/burn layer. Small brush, low opacity, painting incremental strokes of white into the mask, letting the curve begin to work on the red skin. Here is the mask that evolved, and the result it produced. You can see from the brush strokes that I used a wide variety of sizes and opacity settings (the result of keeping my pen in pressure sensitive mode).
The beauty of using a curve like this is that, rather than painting in a single color in color mode, you are applying a full color range. Even though I only entered values from a single sample in each region, the curves distribute the shift over the entire spectrum. Not only do all the regions lighten and shift color, but by painting more white into darker or redder regions those tones can easily be brought into balance with the surrounding pixels.
Acne and freckles respond quite well to this approach. It's also good for gross color shifts, such as lightening shadows. It avoids the saturation problems of dodging away at the shadow and finding out that it's basically a neutral color.
...AND THE KITCHEN SINK
When to use which technique? Seldom does a job allow you to separate out each step. There is a lot of overlap, areas where you could dodge a shadow or just as easily hit it with the healing brush. Then there are times when you're not sure if anything would be effective.
Image (A) shows a really harsh shadow. It needs to be softened, lightened, smoothed and the purple cast needs to be pulled more towards brown. This is a job that will take everything we can throw at it, including the kitchen sink. (Note: the clearly defined area also makes this a perfect candidate for the LAB modification mentioned in the previous section).
I first sampled a shadow that was a more pleasing color and used that as my match values for a curve modification. The mask that I painted is at (B) and the result at (C).
This is an improvement, certainly more compatible with the healing brush, which is what I hit it with next (D). I wasn't trying to wrap things up with this step, so I didn't worry much about being sloppy. I mostly wanted to smooth out the fine hairs, and blend the patch more with the adjacent skin.
Now it's time to dodge and burn. I sampled a highlight and shadow from the rest of the face. (E) shows the hard light layer with my dodge/burn strokes and (F) the result. Still irregular, but the overall tones are much more balanced than in (D). And the areas are small enough that a final hit with the healing brush gets us to (G), and the beginnings of a real patch of skin.
This example isn't perfect, and I'm not sure I'd have done everything this way in a full retouch of the face. But it shows that none of these techniques are isolated. And they're all focused on the same result: removing any anomaly that stands out from otherwise smooth, flawless skin. All the while retaining the illusion that this really is normal skin; skin with texture and pores and maybe even a stray line or two. It's just real skin that's infinitely more beautiful than yours.
[imgr][/imgr]Retouching Skin part 2
Part 1 of this series provided an overview of some of the generally accepted approaches to the problem of achieving perfect skin. The techniques themselves aren't glamorous, though the results can be. They tend, rather, to be boring, repetitive, simple procedures, tasks in which the operator must do most of the work. Grunt work, in other words.
Part 2 (the one you're reading now) and Part 3 will shift over to those effects in which Photoshop does the work and we just add up numbers and push buttons, though a little bit of delving into the esoterica of Photoshop, how it works under the hood, will be called for. But the payoff is definitely worth it. The ideas behind the process discussed here certainly did not originate with me; they can be found on other forums all over the web. I've provided my own particular slant, as I would expect you to do, once you're comfortable with the basic ideas.
What we're going to do is take this image, generously donated for this purpose by ricbuchner, from its original state...
...to here, without lifting a clone tool or healing brush, without dodging or burning or patching or anything else.
Now, it must be said, the image we are starting with comes in pretty good condition, both in terms of the photography, and in terms of the skin quality. No scars, ridges, bumps or gross discolorations. So, of course, we're going to degrade things a bit before embarking on the restoration.
This shows the result of some channel blends that I've been playing around with, splitting up the R, G, and B channels and blending them back into the image in various modes to create more dramatic contrast.
These blends and their possibilities will be covered in Part III, but, as you can see, including the blue plate to add weight also brings out imperfections that were mostly yellow discolorations in the original. An ugly mess. if we could just get rid of the blotches, the gain in contrast would definitely be worth it. It's out of the question to try to dodge and burn them away, and the healing brush would just stir up the soup. In fact, it's such a disaster that the idea of even trying such a move probably would never come up in a normal work flow. Better to just rely on curves for contrast, though I've found that they don't do the job quite as well.
And of course, blurring is a rigid taboo. Any blur that could get rid of the blotches would certainly lose any useful detail. Wouldn't it? Turns out, the answer is "Not necessarily."
THE BASIC IDEA
The theory sound simple enough: blur the big stuff and leave the small stuff alone. We want to lose the blotches but keep the pores and other fine details that make skin texture believable, and, the lack of which, conjours up the dreaded judgment "AIRBRUSHED!!!"
But if it sounds simple, it also sounds impossible, until we actually explore the relationship between blurring and sharpening in Photoshop, specifically between the Gaussian Blur filter and the High-Pass filter.
Rather than get into an elaborate discussion that is ultimately beside the point, try this yourself with any image you wish. Or you can just watch me as I play around.
NOTE: If you chose to pull the example images posted here, your numbers will be different than mine. I worked with an original Hi-res image; these are scaled down for the purposes of illustrating the steps.)
BLURRING AND SHARPENING
• Start by duplicating an image twice into new layers. Leave the original alone. We'll use it for comparison.
• To the first copy apply a Gaussian Blur such as you see here. The radius will vary, depending on the image size and resolution. The goal is a broad blur that wipes out all fine detail, leaving only areas of color. In this case I used a radius of 25, but the numbers aren't important. Getting rid of the details is the point.
While the Gaussian Blur filter is well-known, the High Pass Filter is a little stranger, less user friendly and not so easily understood. It is often used for various sharpening moves. Depending on the radius, it reveals fine detail against a 50% gray background. The larger the radius, the more detail is exposed.
When used as a sharpening tool, the idea has been to combine the resulting layer with the underlying image in one of the modes that both lighten and darken, based on the value of the pixels on the top layer. The usual modes are Soft Light, Overlay and Hard Light, modes for which 50% gray has no effect and so only work on the level of detail revealed.
Go now to the top layer in your file and choose Filters>Other>High Pass.
Like Gaussian Blur, there is only one value to set, and it too is a radius. Use the same value that you used for your Gaussian Blur layer. It will look more or less like this.
Note how each layer contains precisely the information that the other is lacking. It might have been more helpful had Adobe extended the Audio metaphor of the High-Pass filter and called the Gaussian Blur filter a Low Pass filter.
Note how effectively the High-Pass layer can restore detail to the blurred layer underneath, when used in the modes previously mentioned.
All of these are at 100% opacity. If you turn off the blurred layer, so that the High-pass layer is blending into the original image, you will see how the filter can be used as a sharpening method. It's effective, but not nearly as effective as it will be once you understand what is really happening and can exploit the effect to its fullest potential.
TWO SIDES OF THE SAME COIN
Turn the blurred layer back on
Set the blending mode of the high pass layer to Linear Light, and the opacity to 50%. (The math isn't relevant to using the modes correctly; it's enough to know that Linear Light has a much stronger blending effect than any of the other modes. It is the same as using Additive in Calculations or Apply Image.)
With the exception of the very lightest highlights, which have gotten lost in translation, we have not only restored detail, we have virtually returned the image back to its original state. Toggling back and forth from the bottom layer alone to the two layers on top will quickly confirm this.
You can experiment with the opacity of the High Pass Layer: raising it above 50% sharpens the image, lowering it softens, a nifty trick in itself. But not the one we're ultimately interested in.
What this demonstrates is that High-Pass and Gaussian Blur are simply two sides of the same operation. Gaussian Blur is the low pass filter, blocking out all the fine detail and only allowing the largest, most basic areas through. The level of detail is based on the radius setting.
The High-Pass filter works the same way, but in reverse. It blocks the lower bands of detail and only allows the higher bands of information, the fine detail, to pass through.
The radius is the key. Different kinds of detail are maximized at different radius settings. The trick will be to isolate those different "frequencies" of detail, emphasize the ones we want, and minimize the stuff we want to get rid of.
Let's return the image now to the state it was in before we applied the High Pass Filter. You can go the the history palette and click on the level just before the one that says High Pass Filter.
(If, for some reason, your history has gotten scrambled, just set up your layers as before: original on bottom, blurred layer next, and a copy of the original on top)
This time around, we're going to set our blending mode and opacity BEFORE applying the High Pass Filter.
Go to the top layer (the copy of the original) and set blending mode to Linear Light, and opacity to 50%. It should look something like this.
Open the High-Pass Filter and and pull the radius slider all the way to the left. The value is .1 pixels.
The image is magnified to 400%. Note how the level of detail changes as you increase the radius. Your readings will vary somewhat, depending on the resolution of your image, but the same thing will happen as you raise the setting. Different levels of detail will become more pronounced.
What we are left with, after this somewhat complicated demonstration, is really a simple idea: Various settings of the High Pass filter emphasize different levels of detail. Some of that detail is desirable. Some, we want to get rid of. It's actually pretty simple to accomplish.
THE WORKFLOW
It's always a good idea to apply some conventional retouching to the image before embarking on this procedure; large blemishes, warts, brusies, lines and discolorations should be minimized as much as possible. But you don't need to be a fanatic about it. As I said at the outset, I performed no retouching on this image before taking it through these moves, though, as I mentioned, the skin was in good condition to start with. Sometimes, though, it helps.
• Copy the original (or merged layers) into five new layers.
• Name the first layer Blur and leave it in Normal mode at 100%.
• Change the other four layers to Linear Light mode and set their opacities each to 50%. Turn them off for now and return to the Blur layer.
BLURRING
This is the step that wipes out everything, in order that we can selectively replace only what we want. We've used Gaussian Blur so far in our examples to accomplish this.
The advantage with using Gaussian Blur is that it is precise. Knowing the radius of your blur provides you with a guide for measuring the radius for your high-pass filters. The disadvantage is that it is sloppy and hard to control. Color bleeds from one area to the next and with skin that becomes obvious next to dark backgrounds, hair, clothing and shadows.
One way to get around this has been to create a skin mask like the one to the right. Then, using it as a selection, the skin gets copied to a new layer and the blur gets applied to that. This works better, in that dark regions adjacent to skin don't bleed their colors into skin tones. But it creates a softness at those edges anyway, simply from blurring. There are ways around it, but I prefer a different method altogether.
THE LENS BLUR
The Lens Blur filter was introduced in PS7, I believe, and its primary function is to mimic depth-of-field effcts. It uses a grayscale alpha channel to determine how much blurring to apply to different parts of the image. A properly applied gradient from white to black can create a believable effect of blurring increasing with distance. It is far cleaner than trying a similar operations with the gaussian blur. It adheres to the mask precisely, with no pixel/color bleed. And we're not using gradients. Our only concern is with black and white areas¬óto blur or not to blur.
I've been using a Lens Blur in place of Gaussian Blur, with superior results. The downside: the radius settings don't seem to match those of the Gaussian blur, so you will need to work a bit more intuitively. This, as it turns out, is not too hard to do.
So, shiny new skin mask in place as one of your alpha channels (named, hopefully, skin mask, or something to identify it), let's see how it works.
When you open the Lens Blur Filter, there is an impressive and daunting array of parameters. I haven't found much use for any of them other than Radius, Shape and Distribution.
• At the top under Depth Map, select the alpha channel with your mask (which, if named properly, will be easy).
• Leave the Blur Focal Distance at 0. If your preview shows the blurring happening in reverse, check the Invert box.
• I use the Hexagon shape because it seems to be stronger. It's not really important. Choose to taste.
ª At the bottom I check Gaussian for Distribution.
• It's the Radius slider that is of interest. By now you should know what it is we're looking for with this step. Vary the setting until you have those smoothly blurred areas of color.
If you see that you are losing some shadow detail, or that you are getting some color drift from shadow areas into skin tones, click Cancel and return to your mask and paint them out. Notice how in the mask I drew, I excluded the nostrils.
Once your preview is to your liking, apply the filter. It takes a bit longer than a normal Gaussian Blur, and the result is a little strange. Sharp eyes and mouths in a smooth sea of washed out skin. But that will change.
ADDING DETAIL
Up until now, the steps have been pretty straight-forward, and the goals clear. Now it becomes slippery, in that there are an infinite number of ways to set the appropriate values to get the effect desired. It's a matter of taste and preference. I'll take you through the settings that I chose, and try to explain why (not always an easy thing) but it's not as important to match my approach as to become comfortable with what is actually going on. Keep in mind, your numbers will be different. In fact, were I to do this again, my numbers would probably be different. And any of these parameters can be enhanced, modified or expanded.
We have four layers to work with. The goal will be to apply the High Pass filter to each of them, with a distribution of radius settings that more or less evenly captures a full range from small to large detail. Once we determine the initial radius, we can then determine the settings for the remaining three layers by simply reducing the settings each time by an equal value. But what should that initial radius be?
Recall that with a Gaussian Blur, we knew the setting that would return the blur to its original state: it was the same as the Blur radius. We don't have the same precision here, but it's pretty easy to increase the radius of the High Pass filter until the image looks more or less like the original. Our starting radius will then be a value lower than this. (Remember, we're trying to minimize the large detail.
For this image, a radius of 30 pretty much replicated the original state. So I reduced the setting to 20 and that became my starting value, the results shown here. Compare it with the third image (the starting image) and you can see that we've already begun smoothing some of the blotchiness away.
Our ending value will almost always be a radius of 1 pixel (occasionally less, but not often), so it's simple arithmetic to figure out the intervening settings. I chose 20, 13, 8 and 1 as the settings for each of my High-Pass Layers.
This is how it looks after all four layers have had the High Pass Filter applied. Things look pretty ugly; but now we start playing with the layer opacities.
We will drastically reduce the opacities of the layers with the largest radius settings, and increase the overall effect of the layers with the smaller settings.
Here is the arrangement I ended up with. The layer names reflect the High Pass settings each used. I arrived at this by pure trial and error and might well have chosen different values. But these work. Trust your eye.
The opacities are as follows:
20: 20%
13: 80%
8: 80%
1: 100%
I then grouped the two top and two bottom layers into their own layer sets, and adjusted the opacities of these as well.
Low End: 20%
High End: 75%
Finally, I applied a Gaussian Blur to each of the High Pass Layers, to return things to a realist focus. The blur radius increases as the High Pass radius increases. I stayed conservative. Experiment to see what works.
1: .5
8: 1
13: 3
20: 6
And, finally, I grouped both layer sets, along with the blur layer into a master layer set and applied our original skin mask to everything.
NOTE: there's nothing hard and fast about using four detail layers. Any number could be appropriate. You might want to cluster detail layers towards the smaller bands. Each image will have different characteristics and requirements.
And here is the result of all this dithering with opacities. Not too shabby, I think you'll agree.
The color's death warmed-over, but these curves...
...provide a nicely bronzed tone to the skin.
And the addition of a pleasant facial glow (also covered in Part III) completes the effect.
For all the convoluted explanation, the actual procedure takes about 15 minutes.
The variations are infinite. Depending on the opacities of the various layers you can create a crisply focused look or a soft fuzzy look. If the underlying image is fairly well retouched, the entire set of smoothing layers can be reduced in opacity to blend back into the original. Another approach would be to cluster the High-Pass settings towards the smaller end, rather than spacing them out evenly over the full range.
They all add up to the same thing: bluring the big chuncks out of existence, keeping the small bits and making them the focus.
Retouching Skin part 3
This is the third installment of my series on skin retouching, but before we cover any new material (there isn't much, actually), I want to to revisit the techniques that were discussed in Parts 1 and 2 and show how they might all come together in a real world workflow.
As before, my target audience is the typical dGrinner: a savvy photographer who knows a lot about images, and wants to bring their post-production use of Photoshop up to speed, particularly in the difficult area of skin retouching. I assume a working knowledge of Photoshop; this isn't intended as a beginner's tutorial. The use of masking, curves, tools and layers are presented with minimal explanation. I'm working with Photoshop CS1. CS2 offered little to nothing that would have altered the basic workflow described here. CS3 has some interesting new features but I'm not familiar enough with them to determine whether or not they would offer serious enhancements to the process. However, I doubt it. Retouching has never been whizz-bang stuff. It's pretty boring, lots of grunt work and steps repeated over and over. Patience is essential, experience with Zen meditation useful. Most efforts I've seen to streamline the process and eliminate the repetitive steps wind up costing more time while you undo the unsatisfactory result and go back to square one to do it right. If you're still using Version 7, you shouldn't have any problems but anything earlier than that and you're on your own. Perhaps this will inspire you to upgrade.
For this project I want to start with this highly characteristic face, generously dontated by dGrin member HollyC for the purposes of this presentation, and perform a sort of extreme makeover, see if we can turn back the clock about thirty years or so. While this kind of assignment can come up from time to time in advertising work, it's doubtful that anyone would need to make such drastic moves in normal portrait work. However, all the techniques under discussion—reducing and removing wrinkles, creating even skin texture, smoothing the skin tones and face sculpting—all have a place in any portrait workflow.
I faced two problems in preparing these videos. The first, I can't do much about: improvising a presentation in front of a live microphone is a special talent, the lack of which explains why I never pursued a career in talk radio. I ask your indulgence and tolerance for any obvious shortcomings in this area. The other has been the need to structure the work in a series of concisely packaged steps. It would be nice if the real world worked like that, and sometimes it does—one always has a general sense of what things need to be done first, what should be left until later steps—but it's far more an intuitive process, at least for me, than what I suggest here. Quite often I have no idea how I'm going to proceed until I begin. You try A, you try B, you try C, then you go back and try B again, and slowly your course of action takes shape. The idea that a job like this can be crystallized into a recipe, a fixed set of steps, is hopefully optimistic but seldom the case. What's important is understanding the territory, knowing the kinds of things that can be done, and, more important, the kinds of things that really don't work. I've tried to offer that, as well as a clear guide as to how one might apply these techniques to their own workflow.
The rest of this tutorial is presented in a series of videos. You must download each one to view them, and they require QuickTime 7. Just click the links below, download the videos, and then view them locally on your computer. NOTE: These links may not work on IE. Please use Firefox, Flock, or Safari to download these videos.
1 Clone and Heal (27MB)
2 Wrinkles (16MB)
3 Targeted Curves (18MB)
4 Touch Up (7MB)
5 Sculpting (14MB)
6 Skin Mask (9MB)
7 Smoothing (29MB)
Phil
"You don't take a photograph, you make it." ~Ansel Adams
Phil
Thanks for all the time & effort you put into this tutorial (and all the others, too).
Sherry
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Thank youu Ivar for your work.
Very useful, interesting and well done
Mode edit: While it did previously appear that Ivar was the author of this series of tutorials, it is, in fact, our user "edgework" who wrote these excellent documents and produced these videos.