Color from the Camera – Does It Reflect Reality?

Part of a series – Color Managed Workflow

Today – White Balance & Color

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A re-post of a 3-year old blog post of mine

Relevant to the ongoing Color Management series

It explains the effect of camera white balance

and how to deal with WB related color issues

Excuse the length – written in the style of the “old Ed”

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I ended the previous section, Part 1, with this –

Who painted my white bath orange???

These are two images taken straight from my camera without any post-processing. So? What went on here? The left image was made with a custom preset white balance setting (discussed below) and the right had white balance set to the daylight setting. If you read the primer and its link on color temperature you’d know that daylight temperature is in the blue range. The camera wants to make this blue more neutral and to do that needs to add red. However the actual light temperature was incandescent and adding red to that just made matters worse – thus the orange color cast (more than you need to know, but if you’re curious).

Click an image to enlarge it and note three items on the toilet –

  1. A calibrated color reference card on the front of the seat (pure neutral gray plus an area with black and white)
  2. A paper coffee filter next to the reference card. I’m going to save you lots of money with this – while getting you perfect image color; well worth the price of this course 😉
  3. White tissue on the top of the tank

The color reference card has two potential uses –

  1. It can be used to create a custom white balance preset (read your camera manual) for use while capturing the image, and/or
  2. It also can be used in post processing to tell your editing program what part of the image is truly neutral

The coffee filter can be used to create a custom white balance preset (as you would with a reference card but for $10-$50 cheaper)

  • And – about $100 cheaper than the most acclaimed device for setting custom WB presets, the Expodisc
  • Disclosure – I’ve never used and Expodisc but will say
    • that the coffee filter’s results, as measured by how neutral are the neutrals?, is spot on the mark
    • Expodisc benefit claims to the contrary are
      • neither observable by my eyes (R=G=B is neutral, i.e. no color cast, regardless of how it is achieved)
      • nor worth $100 to me as I get the same result with the coffee filter
    • there are those who mock the coffee filter approach but
      • Do your own experiments and decide for yourself
      • Don’t depend on the claims of others – including me
      • Shoot several ways and then examine the RGB components of various neutrals in your image
        • You will need an image editing program that will report the RGB component values to you for any point on an image under the mouse cursor; fairly common function available in most programs
        • If the RGB values are equal to one another – for a point in the scene that is neutral – there is no color cast & your WB setting is correct
        • Neutral is neutral, regardless of whether it came from an Expodisc or a coffee filter
        • If you don’t understand “neutral” reread the final section of the Color Primer

NOTE – a color reference card serves two separate purposes as stated above. The coffee filter or Expodisc only serves the purpose of creating a custom preset. That being said, the reference card is both less expensive and more useful (but buy a good card; it’s worse than useless if it’s not a pure neutral).

The tissues are in the scene to give your eyes a point of reference for white.

So much for the preliminaries but, before reading further, put your camera on your tripod, take it to an indoor room (no natural light), and follow along. You won’t learn to do the steps just in your mind. You need to actually do these things. There’s no time like now.

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Here is the bath again. Three images from the camera with no post processing. White balance (WB) settings from left to right

Auto, Incandescent, Daylight

On the face of it, depending on your color-IQ (click for a fun test), the color of the first two appear to be “OK”. Obviously, the third is way off. Moving beyond “the face of it”, let’s look at actual RGB measurements and see what they tell us. All R/G/B readings were taken by zooming in on the reference card and reading the small white area with my image editing program –

  • Auto                  177/167/128
  • Incandescent    188/173/132
  • Daylight             222/164/64

Several observations

  • None are truly neutral; the two best have a “warm” cast (which some viewers may find pleasing)
  • The G values are similar and are not a principle reason for color differences among the three
  • The greater the difference between the R & B value the greater the red/orange cast; this is shown in the 3rd image with its severe orange color cast
  • Auto did a respectable job in comparison to tungsten – as should be expected
  • The fact that this measured white sample on the card is not brighter (RGB components nearer to mid-250’s) has to do with exposure and not with color balance. This was shot
    • Matrix meter, 0 EV, and
    • The meter’s design goal of making the average of the scene middle gray explains the more or less average brightness of the white

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Next let’s compare the correct fixed camera setting, incandescent, against two custom measured presets. From left to right –

Incandescent, Custom made with calibrated color reference card, Custom made with coffee filter

The difference between incandescent and the two customs is obvious. The customs are whiter – no orange cast. The difference between the customs is less obvious – because they’re the same for all practical purposes. Here are the R/G/B readings –

  • Incandescent    188/173/132
  • Card                  175/174/169
  • Coffee               175/178/179

Observations –

  • Not much to choose from between the two custom measured WB results
  • Although incandescent looked “OK” in the first “shoot-out” – due to a lack of anything better to compare it against – its orange color cast is obvious in this comparison
  • If accurate color is critical, extra measures beyond just trusting the camera’s WB are needed – especially with indoor lighting
  • You can see the problems even in this benign indoor lighting situation; add mixed lighting and you’ll have real problems

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If we shot in RAW and included a reference card (or equivalent) in one image, we could use that image to fix any color problem caused by user WB errors – in all images, not just the reference image. Here’s the image made with the incorrect daylight setting and how it looks after correction during the RAW to JPEG conversion.

The R/G/B measurements for the corrected image are  176/179/180 which are as good as achieved with the custom WB settings in the previous example. This is no surprise; that’s how it’s supposed to work if done right. How this is done in post processing differs from program to program. The basic steps are –

  • Go to an area named something like color balance or color correction
  • Look for an option that allows you to set (define) a gray (neutral) point
    • Keep in mind that even if it says “gray” all that matters is  that the reference is neutral (R=G=B) which includes white, black and all 254 intermediate gray tones
  • Click on your color reference card (your neutral or gray point) in the image – and you’re done.
  • It’s that simple.

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How about if you didn’t shoot in RAW? You’ve got lots of work – possibly followed by lots of disappointment. Google to find color correction suggestions – both good and bad – and then don’t make the same mistake again. Here are three images that show my luck (or lack thereof) in trying to fix a JPEG version of the daylight WB setting. All were done in Photoshop Elements. Each used a different PSE color correction option. The colors are poor although the right hand image, which took advantage of the reference card, is getting there.

With time, effort, a different assortment of programs, prayer, and so on – probably one could do better. BUT WHY??? It’s all so unnecessary. It took me several times as long for each of these poor results as it did to fix the problem correctly in RAW.

  • L   218/178/116
  • M  236/175/87
  • R   133/131/121

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How do we do the coffee filter trick?

  • First read your camera manual for how to create a custom WB preset
  • Next, hold the coffee filter over your lens as shown below
  • Point the camera at the subject (we want it to see the light in the scene)
  • You’ll need to have focus set to manual
    • The camera can’t focus with the coffee filter on the lens
    • If it doesn’t focus it won’t shoot (under normal settings)
    • The camera doesn’t need to be in focus for the preset measurement to work
      • It just needs to see & measure the light temperature
      • To see & measure it needs to shoot – so once again, manual focus please
  • Press the shutter release & do whatever other steps your camera requires to save and use this preset
  • That’s it

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Please understand that with white balance there is no “one right way”. It’s not governed as strictly by the laws of physics as is exposure. Further, how white balance is implemented varies from one camera make to another – and even within different models of the same make. What I’ve explained is what works for me and for countless others including top pros. You will find others who may quibble over some specifics (especially the coffee filter or when to use – and more importantly, not to use – Auto-WB). As I said before, take personal responsibility for yourself & your photography. Experiment, practice  and, in doing so, draw your own conclusions about what is best for you. Above all – have fun!

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Shooting the Rare Super Full Moon

I guess you knew about last night’s super full moona nice NASA piece on it here. If you missed it, there will be another in 18 years or so & you can catch it then (weather permitting; the weather was perfect here last night). 😉

I’ve seen a bunch of images posted on the web from last night. Most of them were of nothing but the moon – boring…. What makes anyone think those shots are any different from one made of a normal full moon? It’s larger you say? “Larger” is simply a matter of lens magnification – use a longer telephoto. If you wanted to take advantage of the fact the the moon was 14% bigger than usual, you needed to make an image that included some foreground matter for perspective.

My choice of a shot was this next one. I knew that it would be a challenge because the scene’s dynamic range far exceeded the camera’s range. I used 9-shot automatic exposure bracketing (AEB) throughout. I shot in the manual exposure mode and biased the initial image by -2/3 of a stop because the correct moon exposure was -4.67 stops from the metered exposure for the scene. So my AEB gave me the following nine exposures -4.67, -3.67, -2.67, -1.67, -0.67. +0.33, +1.33, +2.33, +3.33 (a single exposure based on metering the entire scene would have been 0.0).

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Click on any image to enlarge it.

This image was based on Photomatix Pro’s 2-Image Fusion option (not HDR). I used the -4.67 & +1.33 exposures – shooting 9 different exposures was good since it gave lots of options in post processing. It was subsequently cleaned up a bit using Nik’s Color Efex Pro 3. Note – NONE of my HDR programs (Photomatix Pro, HDR Efex Pro, HDR Photo Pro, and HDR Darkroom Pro – does anyone make an HDR “amatuer” ;-)) were capable of anything that I’d consider showing – except as an example of a complete disaster! Disappointing.

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A variation on the theme is this next one. It was made with Photomatix’s Fusion option as well but used four exposures which were -4.67, -2.67, -0.67., +1.33 together with Fusion Auto instead of the above image’s Fusion 2-Image. Again, no HDR program gave anything except crap.

You do shoot both horizontal & vertical, don’t you? And obviously you have an L-Bracket on your camera to facilitate this, don’t you? And a tripod? What – you think you can shoot these nine shots (some of which run nearly 10 seconds) hand held. Dream on.

I didn’t attempt to compensate for the color balance difference between the two images in post processing – but it’s easy enough to do.

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The above images were made 1/2 mile from home. Although I’ve shot 1000’s of images here in my community, to make this shot I needed some very specific and accurate data regarding where the moon would be and when relative to my intended foreground. I used The Photographer’s Ephemeris to plan my outing down to the last details (and selected this specific location from six that I was considering). The resulting image is precisely what I envisioned – to the last detail in terms of the moon’s location relative to the community clubhouse. Why waste your time (especially if you have to travel a long distance for a rare photo op)? The only uncertainty in this adventure was the technical aspect and I covered my butt with bracketed exposures and four HDR programs (none of which turned out to be worth a damn in this instance except Photomatix’s Fusion Option). Always have a plan and not just Plan A – quite often plans B, C & D are needed, too. One thing that I hadn’t planned for was the surprising lens flares (on the higher +EV exposures) my lens produced (dumb me – never used the lens in this type of lighting; just assumed it would be OK, but not without lots of post cleanup).

This was one of those rare cases for me where the word “envisioned” and reality were more than the usual photographer blather-speak. All in all, of the 100,000+ images I’ve made this one is near the top in terms of technical and execution challenges. Definitely not one to try to figure out after arriving at the scene.

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Here are Silver Efex Pro 2 B&W versions of the two images.

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At age 74, and with an average interval of 18 years between super full moons, I had to make the most of this one. The best thing about it was it got me off my butt and out with the camera – past that my assessment to my wife’s “How was it?” was – “A big whoop!” in a sarcastic tone. 😉

Human Vision & Our Perception of Visual Art

or – Is What We Think We See Really There?

I am fascinated by how the eyes and brain work together to create what we call vision. The eyes collect input and send it to the brain for processing. It’s the brain that decides what it is we see (or think we see). The brain makes its decisions based largely on perceived color and contrast data sent to it by the eye’s sensory elements such as cones and rods. Sometimes these decisions don’t match reality (at least as defined objectively if one measured the visible light’s actual physical characteristics at any given moment) – which occasionally give rise to what we know as optical illusions among other things.

A simple photographic example – The brain adjusts automatically for ambient light effects on the colors we think we see. With our camera, we have to compensate manually with White Balance adjustments. Shoot something white in a tungsten light environment with the WB set to daylight and what color does your camera see for white – orange! Ditto if you’re a film shooter and don’t shoot this scene with tungsten film. But – how about your own vision? What color do you see for your white shirt as you move from outdoors to a room lit by tungsten bulbs? It doesn’t change colors; it’s still white! Your brain did the required adjustments without any intervention on your part. You took it for granted even though (unbeknown to you) colors were changing, i.e. the brain’s decision was to alter reality for you. Amazing!

I had written previously about aspects of vision –

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Using what we know about how vision works is useful for painters – they have control over what appears on their canvas via their use of contrast & colors. Photographers don’t start with a blank canvas as does the painter and, further, what  can be done  with colors and contrasts in-camera is limited. The best we can do at the time of image capture is to be aware of possible pitfalls related to color interactions and the use of negative space and, thus, not fall into avoidable traps.

Here is a famous painting by Monet – Impression: Sunrise. It is the work that led to the name Impressionism for this style of painting.

What I plan to do in this series, Human Vision & Our Perception of Visual Art, is explore the possibility of applying techniques used by impressionist painters to “fool” the viewer’s eye. A very specific technique is used in this painting where the actual painting is shown together with one showing only its luminance (lightness). If you’re not familiar with the HSL – hue, saturation, lightness – color model now might be the time to take a look).

In Monet’s painting, note especially the luminance of the sun. It is virtually identical to that of the sky behind it – surprising considering the appearance of the color version. This is one of the impressionist’s techniques that can result in fooling the eye. It’s called equiluminance for obvious reasons. And so – why might equiluminance fool your eye? The human vision system has two functional areas –

  1. The WHAT part which determines
    1. Color and
    2. Form
    3. It uses the H & S parts of the HSL color model; not luminance
  2. The WHERE part which determines
    1. Spatial properties (location, depth)
    2. Motion
    3. It uses the L part of the HSL color model; not H & S

Our vision determines location & motion based on the output of the Where system. Here’s the kicker – the Where system operates entirely on luminance values (color does not play a role; it’s a completely B&W process). Do you see how that might cause some issues in terms of what we think we see? In the extreme, as our eyes scan the painting (the eyes scan continuously), the Where system may make a slightly different decision regarding where the sun is located each time the eye returns to the sun. Repeat this over and over (as we do) and some people (it varies) may see a slight jumping or shimmering of the sun for this reason. This may explain why movement and shimmering light are often words used to describe impressionist paintings. If you’d like to see an interactive display which allows you to vary both the luminance and color of this Monet painting to see the effect click here.

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In subsequent parts of this series, I intend to explore possible ways to use equiluminance in photographs. Obviously this will be done in image processing. The basic idea is simple.

  1. Create a B&W l(lightness) version of a color photograph.
  2. Adjust the luminance to create equiluminant areas where desired
  3. Save this new luminance version as a layer above the original color image
  4. Blend the equiluminant version with the original color version using the Luminosity Blend mode.

The theory of Photoshop’s luminosity blending mode is that it uses lightness values of the “blended layer” (equiluminant layer in our case) and the hue & saturation values of the lower layer (original color image). This is exactly what we want. We’re, in effect, creating an impressionist equiluminant film. The resulting image will be identical to the original except in those places where the luminance was adjusted – or so the theory goes. Will it make any difference in how we perceive our photograph?

Tune in in a day or two and be surprised (or not). I’m not done with the experiment so I can be surprised along with you. In theory this should work, but in practice- who knows?? We’ll find out (once an engineer, techie – always an….). Here is Part 2.

Getting Color Correct Can be Tricky

If you’re particular about getting color right in your photographs, you know that sometimes it’s not easy.

I had previously written a three part series on the just the first of several color stumbling blocks –

Getting color right in the camera at the time of image capture. Here’s a link to the 1st part. There’s a link at the end of part 1 taking you to part 2 (and – you guessed it, another in 2 to take you to 3).

However, it doesn’t stop with getting color right in the camera.

That’s followed by the mysterious and often complex world of color management – getting your camera, your computer and your printer to agree on what red (or any other color) really looks like. This is the world of monitor calibration and printer/paper/ink profiling – not for the faint of heart. 😉 Here’s what I wrote (a two-parter).

Today, it came home to me that even if I have everything “nailed down perfectly” for my system, all bets are off if I want to show you an image over the internet. I knew this but was never too concerned about it because the fix is up to you – the remote viewer. There’s nothing I can do about it except to alert you to the problem. I can’t fix the “off-colors” you see on your monitor – even if your system is also “nailed down perfectly”. This problem came home to me today because I was making prints for a third party. Things can go wrong quickly if the proof images are uploaded to a website for the “client” to preview. Most likely the colors they’re viewing are wrong – even if their out of camera color is correct and their monitor is calibrated. You’re likely to hear – “Your website’s images don’t match what I sent to you” – if you include a copy of their original for them to compare your pre-print “teaks” against. There are two main problems that cause this –

  1. The “client’s” internet browser may not be color managed. If they’re using IE, for example – except for maybe the IE9 beta – it’s definitely not color managed and the colors that I post will not be the colors that they see, often far from it.
  2. Their monitor may not be capable of displaying the full 16.7 million colors that they paid for and that their graphics card is capable of showing.

You can check to see if you have problem #1 by visiting this site and doing the simple 2-second mouse rollover test there.

For problem #2, you can see if your monitor is capable of displaying the full 16.7 million colors that you expect (instead of less than 2% of that number) by checking your monitor’s spec’s to see if it uses a TN panel (poor) or an ISP panel (good). To determine this, you’ll need to do a little research using Google. If you bought an inexpensive monitor at a big box store, it’s likely to be one using TN technology (which may be fine if image color accuracy isn’t its main purpose).

And you thought that your problems were over once you remember to set your camera’s white balance correctly?! 😉

Part 2 – Overview, Tonal Contrast Adjustment

Overview, details to follow in a later post

Previous post processing (PP) tutorial overview posts –

Here, we’re looking at step #4 in the following sequence of PP adjustments

  1. White Balance
  2. Highlight & Shadow Recovery
  3. Color Contrast
  4. Tonality

(click any image to enlarge)

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To review the results of the previous three steps, here are the images beginning with the original capture and ending with color contrast adjustment

Our image as captured in-camera (RAW),

followed by the next image which shows the effect of  a PP white balance (WB) adjustment,

followed by the next image which shows the effect of  a PP shadow/highlight recovery,

and finally, the results of the Color Contrast adjustment step –

This brings us to the final step in what I consider to be “Basic Post-processing”. Depending on the image and our “artistic vision” more steps may follow but the previous three plus today’s topic, Tonal Contrast adjustments, make up the basic set.

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Tonal Contrast

Color Contrast adjustments, discussed in the previous post, are use to add life to dull or flat images. Now we’ll look at another “contrast” adjustment, Tonal Contrast, that has the same goal.

We’ll explore different ways to improve tonal contrast in future posts. In this overview series, however, we’re mainly interested in seeing the effects of various adjustments on images. I will use the Tonal Contrast filter in Nik Software’s Color Efex Pro 3 to demonstrate. This filter allows us to increase (or decrease) contrast separately for highlights, midtones, and shadows as shown in this adjustment window (shown with default settings) –

Let’s look at several possible outcomes starting with our current image as it looked after the previous three adjustment steps. (Click any image to enlarge it.)

Image after WB, Highlight/Shadow, Color Contrast >>

The default Tonal Contrast settings give us this following image. The image has much more detail due to the increase in tonal contrast – a little too much for me.

Just to demonstrate the effect of different settings, the next three images will demonstrate adjusting just the highlight tonal contrast while leaving the midtones and shadows at the default increase value. I’ve chosen the highlights because the effect is easily seen in the stream. First – increase the contrast to the maximum >>

Next, reduce the highlight contrast setting to zero – that is, no change in highlight contrast from our starting image, but everything else is still increased by the default amount of 30% of maximum (max is arbitrary. We could apply this filter multiple times if we wanted.) >>

Last, the highlight contrast is set to its minimum value, which actually reduces the highlight contrast giving a smoothing effect to the stream as shown in the next image.

The following image is the end of the road based on my taste – plus I’m getting tired. The highlight and midtone sliders were left at the default values of 30. A problem area, from the start, was the darkness and lack of detail in the upper right. To compensate I increased the tonal contrasts for shadows to 60 (double the default value) to deal with this area – and the shadow contrast in the lower left rocks, as well. Overall, the effect was too strong as I noted at the beginning about the default settings so I used the Opacity slider to reduce the overall strength to 50% of the original default value – when in doubt, less is more. And – this is what we get.

I made one final tweak and used the CEP3 Lighten/Darken Center filter to darken the edges very slightly. If you compare the resulting image with the one above you may not even see the difference.

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To complete this long “brief overview” here is the comparison between the original and final images. Lots of small adjustments add up to a big overall change.

 

One nice NX2 feature is the ability to save entire sets of adjustments – like the set of five used in this tutorial. Once saved it can be recalled to make the same (or similar) changes to other images. The changes are not destructive – that is, the original images is not changed but, instead, a complete record of the adjustments made to it are saved separately within the file. I can come back to any image at any time and modify, add, delete adjustments to my heart’s content just as if I were starting from scratch.

Post Processing Tutorial, 2 – Quick Overview, Highlight/Shadow Recovery

Highlight Shadow Recovery Post Processing Overview, details to follow

Previous tutorial overview posts –

Here, we’re looking at step #2 in this sequence of PP adjustments

  1. White Balance
  2. Highlight & Shadow Recovery
  3. Color Contrast
  4. Tonality

(click any image to enlarge)

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And, in the beginning there was………

Our image as captured in-camera (RAW),

followed by the next image which shows the effect of  a PP white balance (WB) adjustment.

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We started with WB first since getting accurate color is critical to all adjustments that may follow. Once we’ve got the color right, we work our way through the other fundamental adjustments – normally starting with those that have the greatest impact and working our way down the list to those that are more fine tuning and/or local in nature.

The next “biggy” is to get the exposure right. The extent to which this is needed depends on the lighting conditions at the time of capture. In the best case, when the light’s tonal range is such that your entire histogram fits easily within the left and right borders, little or nothing is needed in this step. Worst case, you at least had to use excellent technique and equipment such as graduated neutral density filters to control the extreme tonal range (greater than fits the histogram) and/or multiple exposure techniques such as HDR or Exposure Fusion – else you’ve got a mess on your hands.

For help with histograms and exposure see

In this image, we’re in the best case world although there are a few image areas that are brighter or darker than I’d like. We’ll look at how this can be handled and, in later posts, look at more extreme cases.

Before going further below is the histogram for the original image, as captured, followed by what it looks like after the WB adjustment. We see that the original histogram has no shadow/highlight problems to speak of (partly because of the ambient light and partly because this is a thing that I pay great attention to when capturing an image. I look at the preview LCD often – but never to look at the image, I’ve already seen that in the viewfinder. I use a histogram option that shows all three color channels plus the combined histogram together with an option to switch among them and have blown areas flash. If there’s a problem I correct it immediately (PP is too late) by either

You can see that the WB adjustment, alone, had little impact on the histogram – nor should we have expected it to. In the WB post, I noted that the WB correction had the effect of cooling the image a little by increasing the blue component. You can see that illustrated in the blue channel change from the top to the bottom histogram.

If there is a problem with the exposure of this image, it’s that the tones are shifted too far to the left – that is, the overall image is a little too dark. Now, even though it actually was on the dark side – a tropical storm dumped 6+ inches of rain on us that day – I didn’t see things as dark as the image shows. That may just be me, but I get to choose. Although there are a gazillion ways to address this problem, I’ll only consider two here. In a later post, I’ll come back and beat the details to death.

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Since we’re dealing with a RAW image, I’m going to compare two options that only apply to RAW and save the rest for another post.

  1. Exposure Compensation Adjustment (nearly every RAW PP program offers you this)
  2. Active D-Lighting (NX2 & Nikon cameras only, plus you must have this enabled in-camera at capture or it’s not available in NX2. This is not to be confused with NX2’s D-Lighting, no “Active”, which can be used on all types of images from all types of cameras)

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#1 – Exposure Compensation (EV). This, like all RAW camera adjustments, makes the image appear identically to what you’d have gotten had you dialed up the same EV at capture (well, almost but that’s another story). If you saw this histogram at capture and wanted to make the overall image brighter what would you do? You’d dial in positive EV to shift the histogram to the right (brighter) since there’s room before we blow out highlights by running into the right edge. How much? – experiment, practice & learn.

Let’s try 2/3 of a stop (my camera’s EV is adjustable in 1/3 increments, but in PP we can make it whatever we want). Shown here in NX2’s Exposure Compensation window we see the effect of that adjustment. The histogram fills the the entire range from black to white – perfect. The fact that it’s still biased towards dark is more a statement about the tonality of the subject matter than about whether the image is underexposed or not.

and below is the color channel histogram version we used previously but now showing the 2/3 EV effect.

You’ll see in comparing it to the copy of the post-WB histogram from above that we got the right-shift that we wanted.

How about the post-WB vs. +2/3 EV image comparison. At the top is the post-WB, pre 2/3 EV image and below it is the image with WB + EV adjustments. As expected the lower image, with the +2/3 EV, is brighter overall than its predecessor.

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#2 – Active D-Lighting. This 2nd RAW file exposure adjustment option is the exclusive Nikon-RAW only option. I always have this enabled in my camera at its “Normal” setting. If I don’t like the result I can turn it off in PP (not quite the same as off in-camera but close enough) but rarely do. A big reason to have it on in-camera is that if it’s not on then this option is not available to you in PP.

Here is the Active D-Lighting menu from within NX2’s Camera Setting window. The asterisk indicates the value selected in-camera when the image was captured. Let’s see what Extra High does for us since higher general equates to brighter.

The 1st image below is the Active D-Lighting result at Extra High. Below it, for comparison is the +2/3 EV adjustment result we did previously.

There’s not a lot of difference – which is a good thing if both options are aimed at the same thing – but the Active D-Lighting image does appear to be a little brighter. When comparing the two histograms (D-Lighting top and 2/3 EV below) we that the Active D-Lighting did a more thorough job of raising the brightness level at all tonalities. The 2/3 EV did what it should have done, by comparison, and mostly just shifted the entire original histogram to the right. Which is “right”? Which is “better”? The answer is – which do you prefer?

Note that the D-Lighting adjustment did blow out some highlights in the red channel (which is climbing the right wall). This is probably in the red leaves on the rock in the foreground and is easily fixed in a later step.

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I want to go with the Active D-Lighting result. Toning things down later is easier than brightening. Here’s our results thus far with –

  • Original image at the top
  • WB correction effect 2nd
  • WB + Shadow/Highlight recovery third

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In the next post, we’ll build on the above two adjustments and take a look at adjusting Color Contrast which helps with flatness in an image.

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PP Tutorial, 2 – Quick Overview, White Balance

White Balance Post Processing Overview, details to follow

Previous background posts –

Here, we’re looking at step #1 in this sequence of PP adjustments

  1. White Balance
  2. Highlight & Shadow Recovery
  3. Color Contrast
  4. Tonality

(click any image to enlarge)

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And, in the beginning there was………

and it was covered with darkness – and light, sometimes too much light – and, like Goldilocks, occasionally just right.

How do we get this all “just right” – or close to it? The four adjustments listed above -usually done in the order shown –  are basic to almost any image. Here we’ll look at White Balance (WB).

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1. We start with getting the color correct (i.e., WB). Every adjustment that follows depends and builds on correct color. Think about it – if we start with incorrect color and then in subsequent step do things to adjust color (hue & tonal adjustments) we’re adjusting the wrong thing – and probably making it worse, not better.

What do we mean by “correct”? Correct in the sense that’s there is no color cast. No color cast means that white, black and all shades of gray in between are neutral (from here on, when I say gray, white & black are included). Neutral, in turn, means that the red, green and blue (RGB) components of any gray tone are equal

R=G=B = 0 is black

R=G=B = 255 is white

R=G=B = any value from 1 to 254 is a gray-tone somewhere between black & white.

If this condition is not met, then ALL other colors will have a color cast. It may not be perceptible but it’s there – and you don’t want it. In a later post we’ll discuss options for dealing with this in PP. However, the right time to get color correct is in your camera at the time you take the picture. I’ve already addressed color & your camera in agonizing detail in this three part series –

  1. A Color & White Balance Primer
  2. Follow-on 1
  3. Follow-on 2

and they tell all that you need to know – and more. Read it unless you know it already.

One other point – shooting in RAW makes white balance correction a snap. Not shooting in RAW makes white balance correction a crap shoot at best – and your odds of success may not even be 1 in 12 under some lighting conditions. A word to the wise….

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And away we go……

This is the Capture NX2 screen with our test image loaded. Nothing especially different or novel. Processing options and tools across the top, a large window on the right where our selected adjustments will appear, and a histogram.

Note – we’re working with a RAW image. If you choose to not shoot RAW – your bad, not mine; we’ll examine your self made problems in a later post.

We’re here to adjust WB. It’s actually pretty good since it was raining buckets and the camera’s WB setting was for Cloudy, but we’ll go through the steps anyway. In a later post we’ll look at some truly bad WB and how to deal with it. For the moment though, let’s just go through the steps as offered in NX2.

NOTE – All RAW converters provide the means to adjust WB. Be aware that this is the most problematic adjustment when using a 3rd party PP program and not the RAW converter provided by your camera’s maker. Some manufacturers (maybe all) don’t divulge the inner workings of their WB “secret sauce” and the result is that 3rd parties reverse engineering may not provide the same color correction for Nikon cameras as does the Nikon software (and ditto Canon, etc.)

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Shooting in RAW means, among other advantages, that we can change any camera setting – ANY – after the fact and the resulting image will look identical to what we’d have gotten had we actually captured the image in-camera with that new setting. How cool is that? Now there are a few rare exceptions (ISO setting being the most notable and important – mess this up & there’s no turning back), but basically this says that RAW is the ultimate photographer stupidity safeguard. This is why NX2 has an entire adjustment window labeled Camera Settings (which is disabled if you load a non-RAW file, Nikon only). If we want to adjust WB, which is a camera setting, this is where we’d look. The next sequence of images illustrates just a few of the available WB controls. The number & type of options, plus their use, varies wildly from program to program. If you use another program, the “how” of what I’m discussing is up to you. If the options are fewer or the how is harder than shown here, and you shoot Nikon, you may be using the wrong program (or the wrong camera 😉 ).

This next sequence of images illustrate the main WB options available in NX2 (and others?)

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Two main options exist. Set Color Temperature provides a set of standard lighting scenarios from which we can select – and fine tune. The range of scenarios is shown in the two images following this one. Secondly, we can use Set Gray Point to define neutral gray within our image by simply pointing at something true neutral gray (including B&W).

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Below we see the 1st screen provided if we choose the Set Color Temperature option. It tells us that the camera’s WB setting when I captured the image was Cloudy (the 0,0 are fine tune options within Cloudy). This was the correct setting for the situation BUT it also is my standard WB setting. I do not use Auto for reasons I’ll explain when we get to the real details.

From here there are two main options – choose something other than Daylight (Cloudy is one of three daylight options) or fine tune cloudy. Further, one can change the color temperature directly (in some programs this is the main or only WB option) and/or change the color Tint.

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Below we see the lighting scenarios, such as the current Daylight selection, that are available in the New WB drop down menu.

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The absolute most accurate WB can be obtained by actually setting the gray point. This assumes that there is a true gray point somewhere in your image(or that you’ve saved such a setting from another image made at the same time where you inserted something into the picture space such as a gray card for just this purpose. This is a common approach – add a gray card to the image when making your first shot and save this WB setting for use with following images. Read this if you’re not familiar with this concept.

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Choosing the Set Gray Point option provides us three choices – Point, draw a rectangle, or actually specify the Red & Blue component adjustments (better left for fine tuning one of the first two options if they give a color that’s either too warm or cool for your taste).

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If you look near the lower left corner of the next image, you’ll see where I placed the eyedropper pointer to define what I wanted to be neutral. As you’ll see in the image following this one, a small WB correction was made even though I had the correct camera setting at capture. This can occur for several reasons –

  • The sample point, in reality, wasn’t a true neutral point or
  • It was true neutral and the day was not an exact duplicate of whatever the program designers specified for Cloudy in their canned presets. This is most often the case, but in the current image I wouldn’t swear to it as that water I sampled had lots of stuff going on in it. But, anyway…….

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This next image shows the results of the previous Set Gray Point adjustment. The image color has changed on the left and the WB adjustment tool window shows the change – the image has been “cooled” slightly by increasing the Blue component relative to the Red.

You may (or should) have wondered, since neutral is R=G=B, why are we only adjusting R&B. There’s no need to change all three. The fact that both R&B in this case were increased tells us that they were both low – in comparison to the G component with B being even lower than R – and this is the adjustment needed to make R=G=B.

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And here’s what we have in comparison to our starting image after the first of our four basic post processing steps, White Balance. Original is on top and post-WB is below.

Truth be known, I believe the original is closer to what I saw but I’m going with this in order to make changes more readily visible even if not exactly true to real life.

NOTE: In case you think, based on this long, tortuous explanation that adjusting WB is an equally long, tortuous trial in front of your computer – it took 5 seconds to do everything needed to get from the starting image to the completed WB correction. Oh, that I could write that succinctly.