09_Alignment_XXXII_Lab

Instead of RGB, you can use Lab color mode to increase hue contrast in your images in powerful ways that no other color space offers.

How do you do it?

In Lab color mode use Curves to accentuate contrast by creating s or reverse s curves for the a and b but not the L channels without moving the midpoint.

It’s that simple. (Yes, I promise I’ll expand on this.)

However, when you use this technique there are many details that it pays to be aware of.

When To Use It

While this technique can be used on any image, it’s particularly useful when you are processing files that are predominantly one color – forest greens, oceanic blues, sandstone reds, etc. The resulting hue contrast gives these images more life by making subtle variations in hue more pronounced and more three dimensional by accentuating the differences in hue between highlights and shadows.

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Original
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Saturation increased12_Alignment_XXXIV_Lab

Lab a and b channels adjusted

Comparing It To Similar Techniques

This technique is similar to split-toning or cross-toning images, introducing one color into the highlights and another into the shadows, except that the hues are the captured colors accentuated rather than colors that are arbitrarily added. (For this reason this technique won’t work with black-and-white images.)

This technique is similar to increasing saturation or vibrance, which also makes different hues more pronounced but sometimes intensifies them to the point of making them appear unnatural. By comparison the modest increase in saturation boosting hue contrast in Lab produces is surprisingly naturalistic – and you may choose to keep it or not.

To the untrained eye the differences between this technique and others may seem subtle but once you train your eye you’ll appreciate the color richness it offers; they can approximate but never equal it. It’s like comparing the sound qualities of low and high fidelity audio recordings. Lab offers hi-fi color.

What The Heck Is Lab Anyway ?


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Raw2 copy

What Is Color Temperature ?

Of the three elements of color (luminosity, hue, and saturation), hue is the one most closely associated with temperature.  This is a psychological temperature not a physical temperature. Most people associate red with fire or blood (warm things) and blue with sky, water, and ice (cool things), where physically a blue flame is hotter than a red flame. You can identify which hues are warmer and which are cooler by their proximity to the absolute poles of red (warm) and cyan (cool) on the color wheel. When comparing any two hues you can always ask, “Which one is warmer and which one is cooler?”. Even when comparing two variations of the same hue, very often one will be slightly warmer or cooler. Color temperature is part of what creates color variety, which is one spice of life, a very important one, especially when it comes to visual communication.

The Things You Can You Do With Temperature

Many photographers think of color temperature as something to "get right" during exposure but you can also use color temperature creatively in post-processing. You can produce many compelling color effects with color temperature. You can make distant close layers feel closer by warming them and distant layers more distant by cooling them. You can make object feel more three dimensional by warming highlights and cooling shadows. You can add a warm glow that simulates early morning or late evening light. You can  You can even make day look like night, by dramatically cooling it. And every one of these moves will change the emotional tone of an image. Temperature is a critical element for communicating with color.

Lightroom & Photoshop

There are many color adjustment tools in Lightroom and Photoshop that adjust hue. Having used them all since the day they were released (or before) I regularly use four and consider them go to tools worth mastering.


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Constellation_XIX_425

Achieving neutrality in your images is so important. Few things are as important. Why?

Here are 4 reasons.

1 - The color in your images will appear more believable.

Casts make colors seem false. This is true for memory colors like fire engine red, sky blue, and grass green, particularly true for flesh tones (Are you feeling a little bit green today?), but nowhere more true than with neutrals. There can be some debate about which blue is sky blue. On which day? At what time? But there’s very little debate about what gray is truly neutral. Sure those neutral grays can vary in brightness but not hue or saturation. Make the neutrals in your images truly neutral and you’ll make the other colors in your images more believable.

2 – The colors in your images will look more saturated.

When you remove color casts you can see the colors beneath them more clearly. The color beneath appears purer. This effect won’t be as strong as if you had increased their saturation. It will be subtler but more convincing. Oversaturated colors often appear false and you’ll have to work the saturation of your colors twice as hard if they contain color casts. Clean color is a great foundation to add saturation to. You can get the best of both worlds.

3 - Your images will appear more three-dimensional.

Without casts, the colors in your images will have more contrast.

They’ll have more luminosity contrast. When they’re not unified by a color cast, luminosity or brightness values will become more distinct.

They’ll have more hue contrast. Often shadows will appear cooler while highlights appear warmer, making them appear even more different than they already are.

They’ll have more saturation contrast. When neutrals are neutral you’ll get maximum contrast between them and the more saturated colors in your image.

Add these three kinds of color contrast together and you’ll see a dramatic difference in your images. The illusions of three-dimensional depth and volume in our two-dimensional images will be significantly amplified.

Once again, these effects will be powerfully felt but not obvious. Clean colors won’t call attention to themselves because they seem natural, unlike imbalanced images that you’ll need to over-process to get similar effects.

4 – You’ll have the best color foundations to make black and white conversions from.

It sounds strange when you first hear it but color matters even when you’re going to remove it. The maximum hue and saturation separation created by achieving neutrality gives you more control about how dark or light to make hues during conversions to black and white.

5 – You’ll know color management is working.

Neutrals are one of the first things to look for when you’re checking your color management for printing, whether it’s evaluating a viewing light, examining a profile, a rendering intent, or a media setting. You not only look for neutral midtones but also neutrals throughout the entire tonal scale (gray balance). If you’ve achieved both your color management is working correctly. If not, check your system.

I’m sure you’ll find a few more reasons why neutrality in your images is so important.

Achieving neutrality in your images isn’t something you do for all of your images. There are many exceptions. Nevertheless, being able to achieve neutrality in your images a critically important skill. When you know how and why to achieve neutrality all of your color choices become more sensitive, deliberate, and meaningful.

Read more on Color Adjustment here.

Learn more in my digital printing and digital photography workshops.

 


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Antarctica XLII

There are many ways to achieve neutrality in your images. The results they offer are not same. You need to know the differences so you can make better choices and get solutions that are right for you and your images. Explore them and you’ll be more likely to make better choices for your images in the future. Keep exploring them and you’ll open up a world of possibilities within your images.

WB

Antarctica XLII

Lightroom & Camera Raw White Balance Dropper and Sliders

The simplest way to achieve neutrality is to correctly set white balance during Raw conversion, with Lightroom or Camera Raw. Click on the eyedropper tool and click on a target area within the image. It’s that simple.

What’s not so simple is identifying a good target. This will be easy if you photographed a color checker within the image or in a separate exposure at the same time, but few do. If you’re like most photographers you’ll have to identify a good target visually, introducing a margin of error equal to your discernment. Usually the best choices are midtones. This tool also works well with highlights; but they’re more likely to carry color casts that you won’t see at first glance.

After you click on a target, the results can be refined further with the Temperature (blue to yellow) and Tint (green to magenta) sliders.

Remember, you can use Camera Raw as a filter in Photoshop too.

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Normal blend mode

Color blend mode

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Match Color

Match Color is Photoshop’s often unfound and overlooked feature that offers such sophisticated results when neutralizing colors that it’s often surprising. Not all colors will be affected equally – and that can be a good thing. Using Match Color is even easier than using Lightroom / Camera Raw’s white balance eye-dropper because you don’t need to click on a target. Simply check the box Neutralize – and leave all the other sliders and drop down menus alone.


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Sounding XVII

After

Before

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Curves does what other color adjustment tools can’t, precisely adjusting two out of three elements of color (luminosity and hue but not saturation) based on lightness. No other color adjustment tool is as powerful or precise as Curves. Surprisingly, many people don’t use Curves because they find its interface confusing. Yet it’s that interface which offers so much control. You can master Curves quickly and easily with this guide. You’ll be thrilled when you do.

Why Use Curves ?

Curves gives you the most precise control of luminosity. This applies to the whole image and to select areas of an image. This can also be extended to adjusting hue by luminance values.

Curves will help you control and refine masks.

Curves will simplify your Photoshop toolset; you’ll need only a few other color adjustment tools.

You can do more with this one tool than you can with any other.

If you asked me to throw away all of the tools in Photoshop or Camera Raw and use only one tool it would be Curves. It’s that good. It’s that important. I strongly recommend that you not only learn to use Curves but that you master it.

Straight

How To Control Curves

There are a number of things you need to know to use Curves precisely.


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WakeXII_2005_unblended

Before channel blending

WakeXII_2005_blended

After channel blending

Big problems call for big solutions. Blending channels is a powerful color adjustment strategy that can handle even the biggest challenges.

Color adjustment occurs by modifying the tonal structure of individual grayscale channels. Typically, the information within them is adjusted. Less typically, the information within them is replaced.

Blending channels is one way of replacing them. Blending channels takes information from one channel and combines it with information from another. Rather than simply enhancing existing tonal values, blending channels reshapes one channel’s tonal structure with another’s. Consequently, in a most cases, blending channels calls for a substitution of information by percentage not a wholesale replacement of the deficient channel. You usually blend channels from different versions of the same image because blending channels from different compositions produces a highly altered effect.

Blending channels is complex. It often produces additional unintended color affects that may require further correction, such as shifts in hue that aren’t uniform across the tonal scale. Blending channels is neither the simplest nor the most direct path to color adjustment, but in certain situations (files that are exceptionally problematic) it may be the best path. The resulting benefits can be dramatic.

When is blending channels appropriate? In extreme cases. Blending channels is designed to correct major color deficiencies. It’s recommended if a channel is severely deficient, either globally or in select areas. For example, by being extremely light or dark or having very low contrast, a channel may be lacking desired detail. That detail can be found in another channel. Fine-tuning color is best left to more traditional methods of color adjustment.

Many Methods

There are several ways to blend channels; Channel Mixer, Apply Image, Calculations, and using channels as layers. Let’s review the options in detail.

1_ChannelMixer_1

The Channel Mixer (Layer: New Adjustment Layer: Channel Mixer) blends percentages of channels within a single document. It can be applied as an adjustment layer and so corrections made this way can be changed or masked indefinitely. It cannot be used to blend channels from two documents. The Channel Mixer is an excellent choice for making global (the same percentage of channels for the whole image) color to black-and-white conversions. If you want to control black-and-white conversions locally (different percentages of channels for different image areas), use channels as layers instead.

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3_Calculations

The commands Calculations (Image: Calculations) and Apply Image (Image: Apply Image) can also be used to blend channels. With these two commands you can combine any two channels, from different documents, from any layer, at any opacity, with most blend modes. With Apply Image you target the channel you wish to change. With Calculations you blend to create a new document, a new channel, or a new selection. Neither Calculations nor Apply Image can be used as adjustment layers or layers, consequently corrections you make with either of these features are made permanently to an image. With Apply Image and Calculations you can take advantage of two less frequently used blending modes not found with other tools (Add and Subtract) but you cannot take advantage of four frequently used blending modes (Hue, Saturation, Color, and Luminosity) – even if you use the Fade command.

For the greatest control and flexibility use channels as layers. How do you do this? Copy any channel and paste it into any destination as a layer. (Target a channel (click on it); copy it (Select: All; Edit: Copy); then target the master channel (RGB) and paste (Edit: Paste).) You can activate, deactivate, mask, change, or replace this new layer indefinitely. Use Layer Styles (double click on the layer icon in the Layers palette) to determine Blend Mode, Opacity, Advanced Blending (to select which channel is affected) and Blend If options (to determine how This Layer affects the Underlying Layer or which values of the overlying layer affect the values of the underlying layer). What’s more, you get a dynamic preview of any changes you make while you make them. The adjustments you make are flexible, so you can remove them or fine-tune any of the settings future editing sessions. You can even blend two or more channels first, as layers, and then use the resulting new layer to blend with the Background layer. By turning channels into layers, you can achieve everything that the other methods achieve and more.

One File, Many Channels

You may be surprised to find that every file has at least ten channels to choose from. How do you get so many? Consider the file in different color spaces – RGB, CMYK, and LAB. Convert a duplicate file into another color space and you can use any and all of the resulting channels. In fact, you can choose between many, many more channels when you consider that when converting to CMYK there are five different options for generating a Black Plate (None, Light, Medium, Heavy, and Maximum) with two styles for each with two Separation Types (UCR and GCR). But, for the vast majority of situations, I recommend you try to keep things as simple as possible and stick with the standard three.

Be cautious with older files and lower end scanners when blending with the blue channel as it often contains significant amounts of noise. In fact, in some instances, blending channels can be used to replace some or all of the blue channel and thereby remove unwanted noise. Unlike blurring or despeckling, this method of removing noise will not compromise sharpness, but it may produce unwanted color shifts that will require subsequent correction.

A Good Preview

The possibilities are staggering. Is there anything that can help with the decision making process? Yes. A good preview. You’ll want to have multiple documents of the same image in different color modes (RGB, CMYK, LAB) visible at one time to simultaneously see the blended and the blendee. You may even want to make a side-by-side comparison of the component channels of a single document. To do this, use the Split Channels option in the Channels palette submenu. This command will break a single multi-channel document into multiple single-channel documents. (If a file has layers it must be flattened first to use Split Channels.) While doing this with several documents will quickly fill a screen, having the channels separated makes evaluating their relative merits infinitely easier.

Classic Strategies

With so many possibilities, how do you choose one channel as the best candidate to blend with another and how do you use it?

First, identify the channel causing the problem. Then, find the channel with the best contrast in the areas you wish to enhance (at a low opacity) or replace (at 100% opacity). (Stronger adjustments require higher opacities.) Finally, deal with any unintended side effects.

There are several tried and true strategies for dealing with classic problems. First, create detail where there was none before. Second, create contrast that wasn’t there before. Third, add more contrast to existing tonal relationships, if the values can’t be adequately enhanced using Curves.

Look to the Luminosity channel in LAB. Look to the black plate in CMYK. Look to complementary colors. Complementary colors often contain the best possibilities for increasing contrast (Red and Cyan, Green and Magenta, Yellow and Blue), in highly saturated values.

What are you looking for? Better detail in shadows or highlights, better contrast, and a similar tonal distribution. If you change the relative distribution of tones in a channel, you’ll create a non-uniform color shift where some colors will shift more dramatically than others.

13 before-colorcast

Sometimes channel blending produces unintended side effects.

  15 after-colorcast

In most cases, these side effects can be cured.

Blending channels can produce unintended side effects. There are times when it’s better to achieve the necessary effect with this technique and accept its side effects, if the side effects are easier to cure than the initial problem. Typically, all that’s required is a little dose of additional tonal enhancement, either to the master channel (tone and contrast) or a single channel (color). If you find this is not the case, take this as a sign that this is not the right technique for the problem you face.

BlendModes

Layers offer many Blend Modes 

Control The Mix With Blend Modes

As well as controlling the amount channels are blended you can control the way they are blended, by using blending modes. Blend modes determine how new values are mixed with old values. There are dozens of blend modes to choose from.

As color adjustment is achieved by altering the luminance (light and dark) values of select channels (Channels create but don’t contain color or saturation.), when it comes to blending channels, you can limit the number of blend modes you use to those that affect tone; five are particularly useful - Lighten, Screen, Darken, Multiply, and Luminosity.

Lighten displays the lightest values of both This Layer and the Underlying Layer; its neutral color is black (you can’t lighten with black).

Screen multiplies the inverse values of the pixels lightness or darkness. It’s like registering same image in the same location from two projectors. Think of it as industrial strength lightening. Its neutral color is black (you can’t lighten with black). Screen can do wonders for opening up deep shadows. It has a tendency to blow out highlights. Use a contrast mask to remove the effect from highlights.

Darken displays the darkest values of both This Layer and the Underlying Layer; its neutral color is white (you can’t darken with white).

Multiply multiplies the values of the pixels on both layers and then divides by 255. It’s like registering two identical transparencies on a light table. Think of it as industrial strength darkening. Its neutral color is white (you can’t darken with white). Multiply can do wonders for reclaiming subtle highlight detail. It has a tendency to block up shadows. Use a contrast mask to remove the effect from shadows.

Luminosity combines the luminance values of This Layer with the hue and saturation of the Underlying Layer; it has no neutral color.

5_LayerStyle

Enhance The Blend

You can enhance a channel before (or if you use channels as layers after) blending it with another. Use any adjustment method that makes the data better to blend with. As you’re blending with black-and-white images, Curves is usually all you need for it offers the most precise control of tone. For instance, you might increase the contrast of an image before using it to blend with. If you’re using the channels as layers method, all you have to do is group a Curves adjustment layer to the new layer being used to blend with. The contrast of overlying layer can then be fine-tuned as the blend with the underlying layer is occurring. This way you don’t have to guess how much contrast needs to be added before blending, instead you see how much contrast to add while the blend is occurring.

Constraining The Effect

While blending channels may solve problems that other adjustment methods can’t, they may also produce new problems.

In a great many cases, if the tonal distribution of a single channel is substantially altered using another channel, color may shift in an unintended manner. If this happens simply make an additional adjustment to eliminate any side effects. There are times when the color shifts you encounter will be non-uniform (more in some areas than others), which may lead you to making more complex corrections than you had anticipated.

If the problem solved with channel blending and the resulting side effects lie in different areas of the image, consider masking away the side effects rather than correcting them. There are several ways of masking the side effects of channel blending from selected areas. One, simply brush them away by painting with a black brush on a layer mask. Two, use a contrast mask to hold back the effect from highlights or shadows. Three, use the Blend If function in Layer Styles; by sliding the black arrow to the right or the white arrow to the left you drop out the effects from values below or above them – by holding the Option key (Command on PC) you can split the sliders to fade the effect more smoothly.

If you think you’re not used to blending channels, think again. Every time you turn a color image into a black-and-white image you blend channels. In a grayscale conversion three channels are blended to create a single channel while when using either Hue/Saturation or Channel Mixer three channels are blended to equal RGB values. But, when it comes to color adjustment, blending channels is used infrequently, perhaps because it’s so little known. Blending channels is a sophisticated adjustment method. In a majority of cases you don’t need a method that’s this complex. Blending channels is best used in exceptional situations for enhancing originals with substantial problems. If you find that you use this technique frequently, you’re probably not addressing the real problem, the quality of your originals. Nevertheless, when you run into files with severe problems, blending channels will often save the day.

Read more on Color Adjustment here.

Learn more in my digital printing and digital photography workshops.


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