The Overton Technique

My friend, Roxanne Bouché Overton (roxanne_overton on Instagram) has been developing a collection of techniques she calls Intentional Camera Movement or ICM. Many of her images are just that: moderately long exposures (perhaps 1/10 to 1 second) during which she moves the camera up, down, side-to-side, perhaps in a curved motion, forward/back or zoom in/out. As you can see from her Instagram feed, she’s become quite good at it.

But a few days ago I attended a presentation she gave, and at the end she showed the results of another variation on the technique. Here are two of her images. I think you can see why I was intrigued.

Multiples .003.jpegPhoto by Roxanne Bouché Overton

Multiples .001.jpegPhoto by Roxanne Bouché Overton

Based on what she explained, I decided to give it a try. Here are my first results:

L1000356-Edit.jpg“Cityscape #1” by Doug Kaye

L1000333-Edit.jpg“Walk This Way” by Doug Kaye

L1000375-Edit-3.jpg“Cityscape #2” by Doug Kaye

L1000346-Edit.jpg“Bike 363” by Doug Kaye

So, how do you do this? It’s remarkably simple.

First are the exposures. Unlike Roxanne’s other ICM work, these are not long exposures, but rather traditional short-exposure shots. There are multiple handheld images. In the case of “Cityscape #1”, I photographed a street sculpture by walking around it, shooting about 20 images from all 360 degrees. Here are two samples of the individual images:

L1000356.jpg  L1000361.jpg

From Lightroom, I selected all the images, then [Photo…Edit in…Open in Photoshop as Layers]. Once in Photoshop, I selected all the layers, then [Edit…Auto-Blend Layers…]

Screen Shot 2018-08-18 at 10.08.48 PM.png

(Note that sometimes I check Seamless Tones and Colors, but other times it works better without.)

That’s it! Seriously. It’s almost embarrassingly simple. I flatten the image (merge the layers) and save. The resulting image is automatically returned to Lightroom.

What’s going on here? Auto-Blend is typically used for processing focus-stacked images, most often for macro photography. Photoshop creates a layer mask for each image (layer) then analyzes the overall image, one very small region at a time. For each region, it looks at each layer and determines which layer can provide the sharpest sub-image for that region. It then “masks in” that region on that layer. When the layers are merged, you have an image with the maximum sharpness in each region.

But that’s for focus stacking. In this technique, Photoshop is trying to do the same thing, but because the camera or subject have moved from one exposure to the next, Photoshop is merging parts of the subject that may not be in the same region from one layer to the next. You never quite know what you’re going to get, but with practice you can get an idea of what subjects, angles, lighting and lenses will yield the best results. (All of my images above were JPEGs captured with a Leica Q, 28mm, in full-auto mode.)

Not all resulting images are made with 360-degree coverage. For example, for “Walk this Way” I barely moved the camera between exposures. For “Cityscape #2” I purposely moved it a bit up/down, left/right between exposures. And for “Bike 363” I moved about 180 degrees around the motorcycle. In all cases, I’ve cropped the resulting images to emphasize the most interesting portion of the results.

Check out Roxanne’s other work and give this technique a try. It’s a lot of fun. And let me know how it goes!

Workflow: The NDOC “Tree Tunnel” Image

This image I made of a very popular location here in Marin County, California, generated a lot of online feedback. Because I used such a variety of post-processing tools and techniques, I thought it would be an interesting exercise to explain the workflow here. This presentation is an experiment and I look forward to hearing what you think of this format, particularly compared to screencasts and videos.

The slideshow below contains an image for each step in my process. If you hover over it you can pause it or move it forward or back. Below the slideshow is a scrolling area with the corresponding explanations. Click on any image to see it 2x larger. It should work on your mobile devices, too.

[slideshow_deploy id=’3305′]

 

  1. Original. This is the original image, converted without adjustment from a RAW file. Fujifilm X-E1, ISO 400, XF 18-55mm f/2.8-4 R LM OIS, 1/640 second, 55mm, f/5.6.
  2. ACR Basics. My preliminary work in Lightroom or Adobe Camera Raw is just to correct for lens distortion and to map the medium dynamic range RAW file down to the low dynamic range 16-bit image that is used in Photoshop. Here I reduce contrast and recover as much shadow and highlight detail as I can coax out of the RAW file. My goal is to end up with a low-contrast flat image.
  3. Endpoints. The previous step typically yields weak blacks and highlights. Now in Photoshop, I start by spreading the luminosity of the image across the entire dynamic range using a curves adjustment layer to set blacks about RGB=2 and whites at RGB=253. I skipped white-balance correction for this image because I knew I was going to B&W, but this is the point at which I would do that for a color image.
  4. B&W Conversion. I created a SmartObject copy and used Nik’s Silver Efex Pro 2 for the conversion to monochrome. With a more colorful original I typically start by adjusting the color sliders to control each color’s contribution to the b&w version, but in this case I made no global adjustments (color, contrast, brightness, structure, etc.) at all. Instead, I used about a dozen control points in the dark areas of the treetops to bring out some detail there. I also reduced brightness and increased the contrast of the building at the end of the road. I could have done these later, back in Photoshop (I did, in fact), but it seemed like a good time to deal with these issues.
  5. Levels. I’ll often drop in a levels adjustment layer to keep the white/black endpoints under control. Here I also increased the overall contrast after the b&w conversion.
  6. Dodge/Burn Roadway. I didn’t like the lightness of the road. I thought it attracted too much attention to itself rather than supporting the overall composition of the image. (You can switch back and forth between 5 and 6 to make up your own mind.) I also thought the splotchiness from shadows on the asphalt were distracting because they broke up the continuous flow of the roadway’s leading lines. This was a complex step using two curves adjustment layers and luminosity painting, a technique I learned from Tony Kuyper. One curves adjustment layer darkens (burns) the roadway and the leaves near the trees. The second curves layer lightens (dodges) a strip between those areas. The overall effect is to darken and even-out the roadway while increasing the contrast and strength of the lines leading to the building at the end of the road. Once I was done, I decided it was too strong, so I backed off the opacity of the two grouped layers to 78%. The advantage of using luminosity painting or a luminosity mask when dodging and burning is that you can retain and even increase contrast/detail in those areas.
  7. Mid-tone Contrast. So much of this image is in the mid-tones, so I brought out a bit more using a curves adjustment layer with a Basic Midtones luminosity mask.
  8. Dodge/Burn Trees. The light here was beautiful but unusual. Because of overcast skies and the dark canopy of trees, the trunks are actually getting side light from both sides. I wanted to increase the tunnel effect, so I didn’t want too much light on the insides of the tree trunks, particularly in the foreground. That one tree in the left foreground almost looked like it was hit with a strobe. (Compare to step 7.) As with the roadway (in step 6) I used two curves adjustment layers and painted with brushes loaded with luminosity mask selections. This is another good stage to compare, back and forth, with the previous one. It may look like I’m removing contrast and focus from the left and right sides of the frame, which is true. But I’m doing so to focus the viewer’s attention on the center.
  9. The Building. Although it’s not realistic — an overcast sky is almost always the brightest part of an image — I wanted the building at the end of the tunnel to be slightly brighter than the sky. Here I used a curves adjustment layer with an edited luminosity mask to brighten and increase the contrast of the building. After tweaking, I reduced the opacity of this layer to 39%.
  10. The Sky. To complete the effect above, I used another luminosity mask and a curves adjustment layer to darken the sky to just below the level of the building. I ended up weakening this effect too, backing off the opacity to 62%.
  11. Vignette. I wanted to darken selected areas, particularly around the periphery, so I painted with a very weak black brush into a new layer in Soft Light blend mode. Opacity 41%. I didn’t use a luminosity mask here because I didn’t want to maintain or enhance the contrast or detail.
  12. Touch-Ups. I should have done this much earlier in the process, but there were a few bright objects in the close foreground and on the roadway that were driving me crazy. I used a new layer and a combination of the Clone Stamp and Healing Brush tools to get rid of them. It’s hard to see unless you toggle between images 11 and 12 and look closely, primarily at the lower-left corner. I always use these tools in a separate layer because they’re then non-destructive and I can use the Eraser tool on them.
  13. PPW Sharpening. I frequently use the Sharpen 2013 action from Dan Margulis’ Picture Postcard Workflow, version 3.3. In fact, many of the steps in this workflow I learned from Dan. I ran the sharpening action on a copy of the image, flattened that image, then copied it back to a new layer in the original image. Rather then adjust the sharpening in that second (temporary) image, I often just keep the defaults and copy it back at full/normal strength. I then reduce the effect selectively with a layer mask or (in this case) globally by reducing the opacity of this layer to 45% to avoid over sharpening. The advantage of doing it this way is that since I don’t make any changes to the output of Dan’s action, I can re-create it at any time.
  14. Levels (2nd). After so many adjustments, the white & black points are often off, so I use another levels adjustment layer and the Auto button to bring things back into line.
  15. Warm Black. I decided the image was too cool, so I used an action I developed that warms the shadows (a gradient with black as r=9, g=4, b=0). I backed it off to an opacity of 75%.
  16. Original Color. After warming the image, I decided I wanted to see just a hint of the original color: the green in the treetops and some additional warmth in the leaves along the roadside. I added a new layer with a copy of the original image at 20% opacity in the Color blend mode. The effect is very subtle.
  17. Darken. After that warming and color, the image was too light for the effect I was looking for, so I used an unmasked curves adjustment layer to darken the image overall without affecting the endpoints.
  18. Global ACR Tweaks. At the very end, I wanted to add a bit of local contrast and crunchiness, so I created a merged copy, converted it to a SmartObject, then ran Adobe Camera Raw as a filter with the following global adjustments: Exposure=+0.15, Contrast=+6, Highlights=-31, Shadows=+71, Whites=+17, Blacks=+1, Clarity=+20 and Vibrance=+29 (for color). This last step really brought the image to life with a bit of that Halloween feeling I was going for.

(Un)Stiffed by Adobe

[Update: This issue has been resolved in my favor. It was a case of one hand not knowing what the other was doing. Although people on the Adobe Forum (including at least one forum staffer) insisted I didn’t qualify for the Photoshop Photography Program, they were in fact wrong. Not only that, but Adobe had already automatically switched my account from single-app Photoshop CC to the PPP bundle that included Lightroom 5. I accept some of the blame for not going to the My Account page on Adobe.com to check. But since I couldn’t find any info about his in the FAQs or other online Help pages, I thought I’d ask in the Forum.

Special thanks to Larry Nienkark who pointed out that he successfully received this upgrade. It caused me to check to see if I’d received it automatically as well…and I had!]

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Photoshop: Fixing Those Shiny Faces

I was shooting a wedding rehearsal dinner in New York in a restaurant with dark walls and ceiling. No choice: I couldn’t bounce a flash off of anything white, so I had to use on-camera flash. I popped a Gary Fong Lightsphere onto the SB900 atop my Nikon D3s for the job. Although Gary’s “Tupperware” diffuser helps, you still end up with results like this. Obviously lit from just above the lens, and the awful glare from shiny skin.

Andrew & Mikey

But as luck would have it, I just returned from a four-day intensive workshop with color-correction.retouching guru Dan Margulis, where I learned a marvelous technique for improving those blown-out shiny highlights. After some experimentation, I came up with a variation of Dan’s technique. It works so well, I thought I’d share it with you here. The results are shown below.

Andrew & Mikey

The first steps are from Dan:

  • Dan’s technique requires that you switch to the Lab colorspace. Using my variation, you can stay in RGB.
  • Create an empty layer. (Dan uses a duplicate layer. I prefer to work in an empty one.)
  • Using the eyedropper tool, select an area with color near the blown-out highlight. This sets the foreground color.
  • Using the brush tool, paint that color over the shiny area. Dan sets the brush to Color mode. I paint in Normal mode, then change the layer to Color mode.

The results replace the white in the shiny area with color, but keep the luminosity. In Dan’s Lab version, this creates a color that Photoshop can’t render. It’s as bright as pure white but still has color. Since this isn’t possible in RGB or on your screen, Photoshop is forced to convert it to something else, which is why Dan’s technique works. I stay in RGB, then use the following additional steps:

  • Duplicate the layer you just created containing the touch-ups.
  • Switch it to Normal mode.
  • Dial back the Opacity to 30%-40%.

The result is similar to what Dan achieves in Lab, but I think you have a bit more control over it. Dan’s technique preserves virtually all of the contrast and texture. My version allows you to sacrifice some of that texture in order to reduce the highlights further. Give it a try!

Free Photoshop Actions: 1/4- and 3/4-Tone Masks

Inspired by the great work of Tony Kuyper and Mark Lindsay plus the video tutorials by Sean Bagshaw, I’ve just posted this 14-minute tutorial on how to use my new free Photoshop actions to enhance the 1/4- and 3/4-tone portions of your images.

Download the free Photoshop Actions. (My Photoshop Actions for 1/4- and 3/4-tone masks are not compatible with current versions of Photoshop. Beside, the latest version of Tony Kuyper’s TKActions Panel includes a superior tool for generating these masks.)

Luminosity — Photoshop Techniques (Part 1 of 2)

Why Luminosity? Without variations in brightness (tonality) a black-and-white image would be nothing more than a solid gray rectangle. But the same concept applies to color images as well. Without luminosity you wouldn’t be able to see the folds in a piece of fabric or the shape of a mountain. There would be no way to distinguish the light and dark areas of the same color. Luminosity, more so than color, is the key to defining shapes and showing detail in an image, b&w or color.

I’ve been on a three-year quest to understand how best to manage luminosity, particularly in Photoshop. My goal in Part 1 of this article is to explain what I’ve learned along the way towards my current luminosity workflow. Yes, I could simply jump to my current techniques, which I will instead cover in Part 2, but I think the evolution and order of presentation is important to developing a clear understanding of how the more advanced techniques work and how and when they should be used. Sorry to be such a tease, but I think you’ll thank me in the end.

I’ve pulled together these tools and techniques for managing and improving luminosity from a variety of sources. Almost none of them are of my own invention, and even those I thought were so clever turned out to be invented by someone else long before.

Although I’ve included a few examples and even some step-by-step moves, rather than describe every tool and technique in detail, I’ve opted wherever possible to link to a webpage or video that explains the technique better than I can do within the scope of this article.

Note: This article is based on my presentation to the Marin Photo Club’s Advanced Photoshop SIG in March 2013. Special thanks to Scott Loftesness for discovering and researching many of the techniques and resources described here and for providing feedback at various stages.

The Big Picture: Where Does Luminosity Adjustment Fit in the Workflow? After correcting camera/lens issues (chromatic aberration, distortion, white balance) and recovering highlights and shadows in Adobe Camera RAW (ACR), Lightroom, etc., the next step is to work on an image’s luminosity. This is true regardless of whether it’s a color or monochrome image.  In other words, luminosity adjustment comes right after initial RAW processing of an image either in Lightroom or ACR.

Hierarchy. Instead of grouping techniques according to the problems they solve (e.g., putting all the highlight-recovery techniques together), I’ve organized them according to the complexity of the concepts that underlie the techniques. The sequence is also more-or-less the order in which I learned the techniques as I’ve delved deeper and deeper into Photoshop and learned from the gurus of luminosity.

Below is an outline of those increasingly sophisticated concepts. These are not steps in a workflow. They’re just categories of different ways to understand and solve the same problems of adjusting the luminosity of an image. Over time, as your Photoshop skills improve and you learn more about these techniques, you’ll find you’re drawn to using those in the categories farther down the list.

Starting with the most basic, here are the techniques for dealing with image luminosity:

  • Global Adjustments. Alter the entire image using direct image adjustment or adjustment layer (e.g., Brightness/Contrast, Curves)
  • Local Adjustments. Use an adjustment brush (e.g., the Dodge and Burn tools) or a similar tool to affect only part of the image.
  • Global Adjustments with Masks. Use a global adjustment to alter the entire image, but control which portions are affected using a layer mask. The mask might be:
    • a manually created selection (affects specific areas)
    • a channel used as a mask (affects areas according to color and luminosity)
    • a luminosity mask (affects areas according to luminosity regardless of color)
  • Luminosity Replacement. Generate a new luminosity (layer or channel) using techniques such as:
    • use one channel (e.g., red, green or blue) to redefine the luminosity of all colors;
    • use one or more channels to redefine the luminosity of the image, selecting the areas, ranges or luminosity values affected using masks; or
    • creating a separate monochrome version of the image and using that to redefine the luminosity of the color image.
  • Luminosity Painting. Use any of the above techniques to create an enhanced luminosity layer, but apply that layer by brushing with an active selection (based on yet another channel/mask) to control where the effect is applied. I’ll explain luminosity masks and luminosity painting in Part 2 of this article.

Seeing the Luminosity. To view the luminosity of an image — we’ll assume for the rest of this discussion that we’re working with a color image — here are three techniques:

  • Desaturate the image. Image->Adjustment->Desaturate (⌘-shift-U on Mac).
  • In the Channels palette, look at each of the RGB channels separately (⌘-3,4,5 on Mac).
  • To see all ten usable channels (RGB, CMYK, Lab) get the Channels Power Tool (€20, highly recommended). The CPT plugin also simplifies applying channels to layers and masks, which we’ll use in later techniques.

The images below illustrate the before/after effect of the Desaturate command. Notice how similar the previously blue and yellow areas appear because they have very similar luminosity values. Also note that the number “1” on the hull is nearly invisible because it has almost the same luminosity value as the area immediately around it.

The four images below illustrate the contents of the individual color channels. Note, for example, how much difference there is between the blue and yellow areas in the B channel. Yellow is the complement of blue and hence appears very dark in the B channel. Also note how the number “1” on the boat’s hull appears much more clearly in the R channel than in the other color channels or the full RGB image. We’ll look at ways to use the R channel to enhance that detail in the color/RGB image later in this article. (Mark Lindsay’s Channeling Channels is a good introduction to the concepts of channels.)

Global Luminosity Adjustment Tools. Photoshop includes a number of tools in the Image->Adjustments menu for making adjustments to luminosity of the entire image. You may have thought they were too simplistic to bother with, but you should become familiar with each of them. There are many situations in which they’re more valuable than you might expect, particularly when manipulating masks. The same or similar tools are also available as Adjustment Layers, which is the preferred way to use them in most cases since Adjustment Layers are non-destructive. I generally only se the menu-based adjustments to increase the contrast of a layer mask — something I can easily restore if I’m not happy with the results.

  • Brightness/Contrast
  • Curves
  • Levels
  • Exposure
  • Shadows/Highlights
  • Threshold (sometimes useful in mask manipulation)

Below is a before/after example of a global luminosity adjustment (a Levels adjustment in this case).

Local Luminosity Adjustment Tools (Dodge & Burn). Dodging and burning are techniques every photographer should learn. As opposed to global changes in contrast and exposure, these local adjustments are where you really learn to producer richer images with more depth and detail. They’re also the basis for the most advanced technique we’ll cover in Part 2, luminosity painting.

There are a variety of ways to selectively dodge (lighten) and burn (darken) specific areas of an image. The simplest are the Dodge and Burn tools that have been a part of Photoshop for many years.

The Dodge and Burn tools are destructive, so before using them make a copy of the layer you want to adjust. The only way to reliably reverse the effect of these tools in their normal use mode is to use the Undo command. An advantage of these tools, however, is that you can elect to alter only the highlights, midtones or shadows of an image using a pull-down in the tool’s property area.

For example, if you dodge an area of high contrast that has both light and dark areas, the light areas will be lightened while the dark areas will be far less affected. Hence the contrast will be increased.

As we look at increasingly more powerful techniques, we’ll see better and better ways of dodging and burning your images.

Consider Working in Lab Color Mode. When working in the RGB colorspace, particularly when making substantial adjustments, increasing contrast using the above tools has the unwanted side effect of also increasing color saturation.

There are two solutions to this problem. The first (and my preference) is to use these tools in Lab color mode in which you can adjust the L channel (Luminance) independent of the a & b (color) channels.

Rather than convert your entire image to Lab (and possibly mess up some of the adjustments you’ve already made), use Image->Duplicate… and select Duplicate Merged Layers Only. Then convert the copy to Lab mode (Image->Mode), make your adjustments, merge the layers, and finally copy the Lab image onto the RGB version. The Lab image will appear as a new layer, which you can then temper with the Opacity adjustment.


Sidebar: Copying Images as Layers. A few students have told me they didn’t know how to copy one image onto another as a new layer. I couldn’t locate a short video on this topic, so here are the steps in longhand.

  • To start, your images must be exactly the same size (in pixels).
  • Enable the Move tool (keyboard shortcut: v).
  • Hold down the shift key, which tells Photoshop you want the source image to be aligned with the target image.
  • If you’re in tab-view mode, drag the source image to the destination image’s tab, but don’t release either the mouse button or the shift key. Wait for a moment for the destination image to appear, then continue dragging into the destination image itself. Release the mouse button and the shift key. 
  • If you’re in a tiled-view mode, drag and drop the source image to the destination image, then release the shift key.

For example, the left image below is the original. The center and right images show the results of Levels adjustments of gamma=0.35. The center one was done in RGB mode and illustrates the increased saturation. The right image was done in Lab mode and demonstrates that only the contrast has changed.

The Lab color mode is an extraordinarily powerful tool but beyond the scope of this discussion on luminosity. For more information on using Lab color, start with my post on Lab Color and My Workflow du Jour.

Get to Know Blend Modes and Blend-If. From here on, you should be comfortable with both blend modes and the blend-if options in Photoshop’s Layer Style dialog box. I’ve previously written an article on Blend Modes in Photoshop that should get you started.

Dodging and Burning with Blend Modes. Once you understand blend modes there are better ways to do almost anything when it comes to luminosity in Photoshop. Blend modes give us two better ways to do dodging and burning.

The first variation is to make your adjustments on a new layer in Overlay (strong) or Soft Light (weaker) blend mode filled with 50% gray. The advantage is that you can undo your dodging and burning either by using the Eraser tool or by painting with a 50% gray brush. The disadvantage is that you’ll no longer have the option of selectively altering the highlights, midtones or shadows.

The second technique is to paint with a black or white brush on a 50% gray layer set to Overlay or Soft Light blend mode. This has the same strengths and weaknesses as using the Dodge and Burn tools. I recommend two videos on this technique, both of which will also lead you to a slew of other great videos: Aaron Nace’s Dodge & Burn, and Sean Bagshow’s Dodge & Burn. If you’re new to or uncertain about blend modes, these videos will help.

Highlight/Shadow Recovery (Blend Modes). Another simple technique using blend modes is to enhance the brightest and darkest areas of your image.

You can’t truly recover blown-out highlights (or plugged-up shadows) with Photoshop, but you can to some extent darken (lighten) and increase the contrast in those areas to show more detail. (If your original image is in RAW format, you can recover at least some of the highlight and shadow information, but you need to do that in your RAW processing software — Lightroom, ACR, etc. — before bringing your image into Photoshop.)

To darken highlights, duplicate the background layer, then change the blend mode of the top layer to Multiply. This will darken everything, so go into Layer Styles and use the This Layer blend-if sliders (aggressively!) to restrict the darkening to only the highlight areas.

To lighten the shadows, do the same as above, but use Screen mode instead of Multiply and use blend-if to keep the effect out of midtones and highlights.

The four images below illustrate how these techniques can be used separately and together.

Masks and Selections. The above examples of highlight and shadow recovery were created using only blend modes and the blend-if feature. But to combine the recovered images into the final “Both” version I had to use a layer mask filled with a gradient. That’s because I couldn’t create a smooth transition of the midtones in the image (the background mountains and some of the red soil in the foreground) using blend-if.

You’ll frequently find that using continuous-tone masks such as gradients and masks created from the color channels (e.g., the red, green and blue channels) are very helpful in isolating the effect of your adjustments to specific areas or tones within an image. We’ll see much more about this in Part 2.

Because so much detail is contained in the luminosity of an image, you’ll likely find the traditional means of creating a selection or mask (e.g., the lasso tools, the quick selection tool and the magic wand) are far less helpful than you might expect. These tools create all-or-nothing rather than continuous-tone selections, and even if you try to adjust or soften their edges (e.g., using Refine Edge), you often don’t get what you want.

In Part 2 we’ll explore many opportunities to use color channels as masks. Not only are channels continuous-tone, they’re also self-feathering, guaranteeing smooth transitions between selected and non-selected portions of your image.

Furthermore, hard-edge selections create masks that contain no detail except at their edges, whereas masks made from channels retain all the detail from that channel.

Get to Know Channels and Apply Image. The techniques described in the remainder of this article require that you copy images or channels to layers or masks. There are a number of keyboard shortcuts, but they’re hard to remember and not very flexible. The fundamental tool for copying images or channels to other places is the Image->Apply Image… dialog box.

I suggest you read Harold Davis’ Using Image Apply Image on photo.net. Don’t be scared off by the length of the article. Alternatively you can search the Internet for Photoshop Apply Image Video to find many video tutorials on the topic.

Luminosity Enhancement Using Channels. The objective of luminosity enhancement is to bring out detail in desired areas of an image. Bringing out detail generally means increasing contrast within those areas, for it’s contrast that allows us to see detail.

Unless an image is strictly black-and-white, there is always more contrast in one of the color channels (R, G or B) than in the image overall. The most basic of the luminosity enhancements techniques is to replace the overall luminosity of the image with the luminosity of the color channel that has the most desirable contrast and therefore detail (using the Image->Apply Image… dialog as shown above).

The following channel-replacement technique is recommended by many of my personal Photoshop gurus: Mark Lindsay, Lee Varis and Dan Margulis. A good way to learn more is to start with Lee Varis’ free 10-Channel Workflow videos (Part 1Part 2Part 3Part 4). Part 2 deals specifically with the steps to perform this enhancement:

  • Open the Channels palette and select the best channel. That’s best in terms of contrast in the area you want to enhance. If you have the previously mentioned CPT plug-in, you can use it to generate a preview of not just the RGB channels, but also the CMYK and Lab channels.
  • Add a new empty layer and change its blend mode to Luminosity.
  • Use Image->Apply Image…  (or the CPT plug-in) to load the new layer with the selected color channel.
  • For even more detail, use a Curves or Brightness/Contrast adjustment to increase the contrast in the desired area.
  • Optionally, if you want to restrict the enhancement by color and/or luminosity, use the blend-if sliders in the new layer’s Layer Styles dialog box.
  • As a last resort, if you want to restrict the enhancement to a specific area, you can generate a layer mask. Using the bend-if method is preferred because it can be feathered, whereas creating a mask using selections often causes undesirable hard edges.
  • Note that if you’re working in the Lab colorspace, you can simply replace the L (luminance) channel rather than generate a separate layer in Luminosity mode.

The before/after images below illustrate the effect of using the red channel as the source for the luminosity layer in Lab color mode. Note that the “1” on the hull is much more clearly defined. The blend-if sliders were used to reduce the contrast increase in the blues, and this could be carried further using more of the techniques described in Lee Varis’ videos.

Doug’s Luminosity Shortcut. Although I cut my luminosity teeth on the channel-replacement techniques recommended by Varis, Lindsay, Margulis and others, I’ve pretty much switched to a simpler, quicker and in some ways more-powerful technique. I arrived at this technique by asking myself, “If the best luminosity for a color image is a good black-and-white image, why not just use the best tool for making b&w images?”

My personal favorite b&w tool is Nik’s Silver Efex Pro 2, and I’ve described the method of using that plugin for managing the luminosity of color images in Silver Efex Pro for Color Images.

Luminosity Masks and Painting. It was less than four months ago that I published Lab Color and My Workflow du Jour, an article whose title suggests that I’m quite frequently changing how I process images. While I’m still using some of the du Jour techniques and the Silver Efex Pro shortcut as appropriate, I now find I’m more often using another workflow based on luminosity masks. I find them to be extremely powerful, and once mastered, there quite easy to use.

To Be Continued. In Part 2 of this article I’ll explain the next level of luminosity adjustment techniques: luminosity masks and luminosity-mask painting, both of which I first learned from Tony Kuyper. If you can’t wait, see Tony’s articles on Luminosity Masks and Luminosity Painting.

Blend Modes in Photoshop

Last week we started an Advanced Photoshop SIG (special-interest group) at our local photo club. Based on a survey of our members, I chose Blend Modes as the topic for our first meeting. Here’s a cleaned-up version of the notes I used in preparation.

Here’s an image of 0%/25%/50%/75%/100% that you can use in a layer to see the monochromatic effects of blend modes. (Public domain. Click to enlarge.)

For example, here’s the above image in Overlay mode over another image. Note that in this mode, black darkens the image, white lightens the underlying image and 50% gray causes no change.

Here are some tutorials and tools:

(Thanks to Scott Loftesnsess for his recommendations to the above list.)

These are some of the techniques I demonstrated:

  • Scrolling Through the Blend Modes: Select the layer you want to change in the Layers palette. Select the Move tool. Use Shift- and Shift+ to scroll through all the blend modes and see their effects.
  • Difference Mode: Just as a demonstration of the more obscure and creative blend modes, set your brush to white in Difference mode at 20% opacity and paint directly on your image or a copy. Now change the brush to 100% and see what happens. (Don’t forget to return your brush’s blend mode to Normal, otherwise you’ll wonder why it doesn’t work correctly later on.)
  • Dodging: Duplicate the image, set to Screen mode, add a black mask and paint on the mask with 20% opacity white.
  • Better Dodging (Levels Adjustment Layer Trick): Duplicating your image in a new layer substantially increases the size of your .psd file, so instead of the above, try dodging this way: Add a Levels adjustment layer set to Screen mode. Paint 20% white on a black mask. Just as easy as above, but your layered files will be smaller.
  • Burning: Add a Levels adjustment layer set to Multiply mode, paint on a black mask with 20% white.
  • Even Simpler Dodge & Burn: All of the above are just experiments to show various options, but perhaps the best way to dodge and burn is to create a new blank layer set to Overlay mode, but don’t change the levels. (It’s just a dummy adjustment layer.) Paint with 20% white to dodge and 20% black to burn. Your file size will be small and the technique is totally non-destructive and reversible. You can erase your adjustments using the Eraser tool or a brush set to 50% gray color.
  • Exposure Control w/Gradient: In a new layer, draw a black-to-white gradient from top to bottom. Set to Overlay mode and adjust the opacity. While this works, you can’t move or change the gradient. So instead…
  • Gradient in a Layer Style: Don’t create a new layer. In the image layer, open the Layer Styles dialog (fx icon at the bottom of the Layers palette or just double-click in the blank space to the right of the layer’s title). Select the Gradient Overlay and (!) check the box. Select a black-to-white gradient (click the Reverse checkbox if necessary), set the gradient style to Linear. Play with Scale and Angle. Then switch the blend mode (of the gradient, not the layer) to Overlay and adjust opacity. Note that you can drag the gradient in your image area to reposition it! Now you have a non-destructive, changeable gradient tool.
  • Vignette in a Layer Style: Like above, but use a black-to-transparent gradient instead of black-to-white and the Radial gradient style. Experiment with the Overlay vs. Soft Light blend modes and the opacity. Unlike Lightroom you can’t change the squareness/roundness of the vignette, but that’s outweighed in some cases by that fact that you can reposition it.
  • Increase Luminosity Contrast: Duplicate the layer, set to Overlay blend mode and adjust the opacity. Works, but it pushes the lights and darks to extremes.
  • Better Way to Increase Luminosity Contrast: Duplicate the layer, from the menus select Image->Adjustments->Desaturate. Change the blend mode to Luminosity and adjust the opacity. You can also use a curves adjustment (to this layer only) to increase the contrast of the desaturated image and even use a mask to selectively add contrast in only certain areas of your image.
  • Even Better Way to Increase Luminosity Contrast: Use the Channel Power Tools plugin (see above) to preview all ten channels (RGB/Lab/CMYK). Select the channel that shows the most contrast in the desired portion of your image. Create a new layer and use CPT to apply the selected channel to that layer. (Or use Image->Apply Image… from the menu.) Select Image->Auto Contrast if necessary to quickly get a contrasty version, particularly if you selected either the Lab “a” or “b” low-contrast channel. Set the blend mode to Luminosity and adjust the opacity. Again, you can apply a Curves or Brightness/Contrast adjustment and a mask as above.
  • High-Pass Sharpening: Duplicate the layer. Select Filter->Other->High Pass… from the menu. Adjust the radius to define edges. Use a curves layer or Image->Auto Contrast or a Brightness/Contrast adjustment layer to increase the contrast, then set the blend mode to Overlay, then adjust the opacity.

I hope you find some of these techniques useful and that they help you understand the power of blend modes in Photoshop. Feel free to leave your feedback here.