Sagelight Pro Series: Pro Saturation Function

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(Image Saturation with Sagelight Saturation)

Sagelight Pro Series Articles and Videos

This series of articles and videos detail some of the more professional-level, sometimes less-obvious qualities of Sagelight.

For example, why use the Sagelight Pro Saturation Feature when there are already two methods of saturating your image in the Quick Edit and Pro Quick Edit Modes (i.e. the Saturation and the Power Box Vibrance)?

The answer is that the Sagelight Pro Saturation functions provide just that – a set of professional-level saturation functions that encompass some traditional methods (such as XYZ, C*I*E LAB, Hunter LAB), as well as Sagelight-developed methods created specifically to answer problems with saturation.

The article below is more verbose than most Sagelight articles.  It’s a combination of an introduction to the Pro Saturation feature and an outline detailing why such high-level functions exist in Sagelight.

At the end of the article, the idea is to have an understanding of the very high-level nature of Sagelight, how it is used internally (i.e. much of the technology in the Pro Saturation function is used elsewhere in Sagelight automatically), as well as how the Sagelight engine takes image processing at a very serious level.  By providing the Sagelight Pro Saturation function, this gives you access to the Sagelight engine functions, without it getting in your way of the normal, easy editing process elsewhere in Sagelight.

note: for before & after image examples and a more detailed description of the science behind Sagelight Saturation and Vibrance methods, see these two articles:

Click here for more information Sagelight Saturation Technology

Click here for more information Sagelight Vibrance Technology

Introduction

As it turns out, the subject and concept of Saturation (and Vibrance) is both more subjective and technically challenging than just about any other traditional, mainline image processing feature.

There are many different types and color spaces and algorithms that can be used to add color to your image.  They’re all different, and most editors provide just one type of saturation.

Sagelight offers 8-10 saturation algorithms in the Pro Saturation Feature, and uses various saturation models automatically elsewhere in Sagelight, depending on the needs of the particular function.

cats

 

(highly saturated image)

 

The Problems and Challenges with Adding Color to Your Image

The reason the Sagelight Pro Saturation function exists, as well as providing many saturation models, is because of the technical problems and subjectivity involved in adding color to your image.

 

Saturation is a Challenging Technical Process

Saturation models, from an algorithmic and mathematical standpoint, can be very complex, especially when you want them to work in realtime.  All traditional methods of saturation have problems:

Noise.  One of the biggest problem with many saturation methods is that they can add noise.  For example, HSL saturation is the most color-faithful of the saturation methods, maintaining the same basic hue as you add color to your image.  However, it can also add a large amount of noise to your image as well as turn many colors into a neon-like brightness compared to other colors in your image.  Sometimes this looks nice on a random image, but it is technically incorrect and can lead to unrealistic-looking results.

Other saturation methods can cause more noise than others.  Sagelight’s saturation algorithms were designed to keep the noise at a minimum, as when noise occurs while saturating, defined speckles and color edges can appear in your image.

  • Jpegs and Noise.  In many cases, the noise caused by adding color is exacerbated when an image starts as a JPEG.  In some ways, the noise issue with adding color is inherited by the technology we now use to compress images. Noise when adding color also occurs in non-Jpeg (i.e. RAW, .TIFF images never saved as a JPEG image), but it shows much faster and stronger with JPEG images.
  • This is one of the reasons why Sagelight saturation algorithms (Sagelight Saturation, True Color, and Hybrid) were developed, because editing with an image saved as a JPEG can be much easier than starting with the RAW.  While starting with a RAW image from your camera is technically more precise and much less susceptible to edges, speckling, and other problems associated with adding color and elsewhere in the editing process, it can also be much more cumbersome and difficult, since you have to deal with a number of elements the camera performs automatically (such as color balance, sharpening, light adjustments, etc.).
  • Sagelight has extensive RAW functionality, but doesn’t take an opinion on editing with RAW or JPEG, as both have their advantages.   However, if you see noticeable block-shaped edges in your image while adding color, this is probably due to the JPEG compression.  When this happens, try different saturation modes to remove it.

Color Fidelity. Most saturation methods will start to change some of the colors in your image as you add saturation. For example, XYZ-based saturation can tend to move your image to the warm and yellowish tones, and skies can turn into an undesirable CYAN with XYZ, or C*I*E LAB saturation.   This can be a problem if it happens with every image, because your images can start to take on the same ‘look’ from image to image.  

If this is such a problem, why does Sagelight offer XYZ and C*I*E LAB saturation? 

The reason many different saturation methods, including XYZ and C*I*E LAB saturation is offered is because, for as much as these methods can change colors in your image, they can also provide very nice toning effects on your image.  Sometimes, the ‘technically right’ color is not the most desirable.  Many images look nicer with a warming effect, and the XYZ and C*I*E LAB (or other) saturation methods can look visually nicer, as they also tend to deepen the colors in your image, even when not technically correct.

Light Fidelity. Many saturation methods will also change the light value of areas of your image, depending on the color.  For example, you may have noticed with some editors (or traditional Sagelight saturation modes) that greens tend to brighten.  This happens with other colors, as well.    As with the Color Fidelity issue, this can sometimes make your image look nice, but can also go the other way and make your image look unrealistic.

Color Overruns (blowouts).  In just about all saturation methods, bright colors (such as red) can overrun and become flat, causing your image to look unrealistic.  Sagelight has a number of controls to help with this problem, and the Sagelight saturation algorithms were written with this issue in mind.

Saturation is Subjective

Saturation is also subjective.  I could adjust the saturation on an image with the algorithm that, for me, does the best job in adding color to my image, where someone else would choose another saturation algorithm.  For example, I tend to like images that stay more neutral or ‘cool’, where other people like more warm images.  Where I see an awful yellowish-green underlying hue, someone else may see a nice, colorful, warm and natural image — and this is from actual experience.

This is another reason the Pro Saturation exists in Sagelight.   Since saturation methods vary greatly, having multiple methods (which you can switch between easily) allows you to get the look you prefer in your image.

A good example is the sky.  While some algorithms move the sky to a deep blue, other algorithms will move it more to a cyan.  I tend to think the cyan is ugly, but others may find the sky going deeper blue unrealistic from a photographic perspective.  Choosing between algorithms allows you to control more of how your image is saturated.

Another reason multiple saturation algorithms are useful is because the same algorithm that might turn the sky that ugly cyan color is the same algorithm that may (and often does) work out better for another picture.

Since all pictures are different, each saturation method will work differently with each image.  That is to say, while each saturation method has its distinctive qualities, they work differently for each type of photograph.
 

Getting Used to the Different Saturation Modes

Once you get experience with the different saturation modes, you will begin to know which type of saturation is typically better for your image.  For example, I mentioned above that some algorithms tend to move the sky to an ugly cyan (in my subjective experience, that is), while others move it a deeper blue.  I tend to like the deeper blue, so I use those algorithms for the type of picture that needs it.

Once you’ve seen the same type of image a few times, it is easy to realize that C*I*E LAB and XYZ, for example, will turn the sky more of a cyan, where the Sagelight saturation methods will turn the sky a deeper blue, as well as which algorithms have the same general effect for other image qualities.
 

The Best Overall Saturation Algorithm

Sagelight Hybrid Saturation

While all of the saturation modes have their strengths, the best overall mode is the Sagelight Hybrid algorithm.  This tends to warm your image and deepen colors simultaneously.   You can also try the Hunter LAB algorithm which works well with most images.  Sagelight’s Hybrid Saturation tends to offer deeper colors and does not turn your image quite as yellowish or warm as Hunter LAB saturation.

note: when using the Sagelight Hybrid Saturation algorithm, try checking the “Keep Luminance” checkbox, as this can sometimes work better (i.e. it’s always worth trying).

Sagelight Saturation

From a technical standpoint, Sagelight Saturation is the best overall saturation.  The reason Sagelight Saturation is second in the list is because, as mentioned above, the most technically correct algorithm isn’t always the ‘perceptual’ best.  For most things, the Sagelight Saturation will work well, which is why it is the default saturation method in the Pro Saturation Controls.

However, Sagelight’s Hybrid Saturaiton works in the middle ground and, on an average, is the best ‘go to’ saturation method.  Sagelight’s Hybrid Saturation is the most predominantly-used saturation method in Sagelight in other functions, and is the basis for the Vibrance in the Power Box (Quick Edit or Pro Quick Edit Mode)

 

The Strengths of each Saturation Method

Each saturation method has some basic strengths.  For example, Sagelight Saturation works well for deepening the colors in your image and created a well-defined edge between colors that can be a nice result.  C*I*E LAB saturation has a strength in working with skin tones, and the Sagelight Hybrid and Hunter LAB saturation methods have a great warming effect on your image, as does XYZ saturation.

For more information on the strengths of each saturation methods, go to the Sagelight Pro Saturation Quick Reference, and then hover the mouse over the numbered tags for each saturation method; they are described in detail in this section.

Selecting Between Saturation Algorithms

It is easy to switch between saturation algorithms.  You can simply select them by clicking the mouse on the Saturation label to the right, and you can also use the mousewheel to move the saturation algorithm up or down.

 

prosatmask

 

Masking in the Pro Saturation Controls

The Sagelight Pro Saturation feature includes simple, powerful masking.  This will be explored as a separate post and possible a video tutorial. You can also mask with the saturation in the Pro Quick Edit mode, though the masking in the Pro Saturation controls is more oriented towards quick masking for adding or removing color.

In short, the masking in the Pro Saturation function provides powerful features to specifically select or avoid areas.  In a lot of cases, adding color to your entire image can look unrealistic.  But, adding color to just one subject or, conversely, avoiding a subject, can make the image look much more realistic while adding color that will make your image vibrant and crisp.

See the Sagelight Pro Saturation Quick Reference for details, which describes the masking in detail (just move the mouse over the numbered tabs for each masking control).

 

Sagelight Saturation Algorithms

The following details the Sagelight-developed saturation methods.  Each method was developed to answer specific problems that can occur with traditional saturation methods.

 

Sagelight Saturation

 

Sagelight Saturation was developed specifically for Sagelight and is a very high-level, algorithmically intense saturation. Sagelight saturation works by keeping the color fidelity and luminance fidelity as tight as possible, allowing for deep saturation with little or no noise compared to some other saturation methods. Sagelight saturation is designed to deepen the colors as you add color to your image, as this typically works better for an image. However, you can control this with the “Keep Luminance” switch, which tells Sagelight Saturation to preserve the luminance of the image.

Sagelight Saturation is also designed to move the colors to their primary colors as you add color to the image.  This allows the colors to deepen.  For example, a blue sky will typically turn to a darker blue instead of a cyan, as the color is moving to the primary blue.  Green plants will move more towards a deeper green than a yellow, and deep orange skies will move towards a deeper orange/red as you add color.

You can also control this factor with the “Protect Colors switch, which tells Sagelight Saturation to maintain the original HUE, which can prevent deepness, but can also be useful in keeping certain colors from moving to their primaries.

Sagelight Saturation has many options to help with getting the best color for your image.  See the sections on Keep Luminance, Protect Colors, Clamp Colors, and the More switch next to Clamp Colors. in the Controls Quick Reference

 

True Color Saturation

 
True Color Saturation is another Sagelight-developed saturation method.  True color is based on HSL saturation, but maintains the light and removes the noise and neon-effect that HSL saturation can often created.

HSL saturation is notably the most accurate saturation method in terms of color accuracy, but also creates a large amount of noise and light problems with your image.

Sagelight’s True Color Saturation increases the saturation in your image with the HSL component, but also maintains the light and color in your image, which prevents the traditional problems with HSL saturation.

If you wish to use HSL saturation in Sagelight, use the Power Curves with the Chroma channel in HSL mode.

 

Hybrid Saturation

Sagelight’s Hybrid Saturation is an intensive saturation that also warms as well as deepens colors. Recognizing that while it’s technically not accurate, the warming effect that some saturation models (i.e. XYZ, Hunter LAB) have can be very useful to your image, Sagelight’s Hybrid Saturation was developed to have similar properties of Sagelight Saturation, to protect your image from noise as well as deepen colors while staying truer to the original color ‘direction’ (more below).

In it’s default mode, Hybrid Saturation deepens the colors of your image while warming it.  In some pictures, the result is similar to Hunter LAB, and with the “Keep Luminance” button checked, they are even more similar.

However, Sagelight Hybrid Saturation, like Sagelight Saturation, starts drawing the colors of the image to the primary color, allowing it to deepen and stay much more crisp than Hunter LAB or XYZ saturation as color is added.  This means that skies become deeper blue, and greens become deeper green, where Hunter LAB and XYZ saturation will move the warming more to a central color.  Sagelight Hybrid Saturation allows you to warm your image while simultaneously deepening the colors in your image.

In most cases, this works out well.  But, it is always worth clicking between the other saturation methods (such as Hunter LAB or Sagelight Saturation) to see the difference.

 

Quick Reference

 

prosaturationquickreference2

 

Click here to view the interactive quick reference for the Sagelight Pro Saturation controls.

This section explains all of the controls as well as describes each saturation algorithm and their strengths.

 

mountains-small

Conclusion

Adding color to your image is highly subjective.  The images above, for example, may be to your liking or not, depending on what you personally like to see in your picture.

Adding color to your image is also one of the primary things that can change your image with great effect.

This is one of the primary reasons the Sagelight Pro Saturation function exists – to give you as many options as possible to add color to your image to get what you want.

Every saturation algorithm is different and will treat your image differently, depending on its makeup. Most editors use just one algorithm for saturation.

Sagelight doesn’t take the idea of saturation lightly, giving you access to many different saturation algorithms, so you can use the one that fits your image the best.  The different subjects, and colors in your image can make one saturation algorithm more useful than others.

Saturation is also a very technically challenging and mathematically intense concept.  As such, it is hard to define one saturation algorithm that is the ‘best’. There are inherent problems with saturation algorithms, which include adding noise, changing color, changing the light value, and color overruns.

Saturation algorithms developed just for Sagelight (Sagelight Saturation, True Color, and Hybrid) were designed to specifically work with the problems associated with adding color to your image.  They are designed to reduce noise, keep as much color fidelity as possible, and to deepen the colors in your image (as a default option) to add color to your image that looks as natural as possible.

Sagelight’s Hybrid saturation is used in most places around Sagelight as the default saturation algorithm, and it has been designed as the best overall saturation to use, in general, as it fits the needs of most images well, by providing a slight warming tone to your image while also deepening colors and staying true to the main colors in your image.

In general, just adding a little bit of color to your image works out well in the main Quick Edit and Pro Quick Edit modes.  But, if you’re looking to get the most out of adding color and want to explore how you can better control and shape how color is added to your image, then you can use the Sagelight Pro Saturation Function to explore many more options.

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