Tag Archives: White Balance

The 5 Most Used Photo Enhancement Techniques

We have been watching ourselves over our shoulders – yeah, kinda weird, right? Our goal is to figure out what it is we do the most to fix and beautify our photography – night photography in particular.  We cover nearly all of these topics in greater detail in each of our NP150 – Photo Manipulation Webinars but we will hit the highlights here. So what are the 5 most used “tricks”?

  1. White Balance / Color correction
  2. Noise Reduction
  3. Exposure and Contrast enhancement
  4. Sharpening (and de-sharpening)
  5. Healing and Cloning

The first two topics are tackled below. The next two in the following article.  Healing and cloning will get it’s own short article.

First to be clear our goal is usually to make a compelling photo, not merely to represent reality. We do prefer realistic over bizarre, but we are not opposed to removing telephone wires and other distractions.  We DO prefer natural looking scenes and eschew the over-the-top contrast and color saturation that seems to be the rage these days.

White Balance

We hate to be the first to break the news, but your camera is pretty clueless about what color white is. The camera will take its best guess. Our experience with night photography is that the camera choice is usually wrong – or at least unappealing. At its core white balance requires adjusting the red, green, and blue colors so that an area that should have a neutral gray or white color is actually gray – not tinged red, blue or green. When shooting at night, understand that every light in the scene – including stars – has a different color bias (tint). Sodium vapor lights for example are horrendous. Sodium vapor lights used in many streetlights are predominately yellow-brown and almost monochromatic. Under sodium vapor lights it will be impossible to achieve a natural color spectrum. You may want to adjust different parts of a night image separately.  You may have to compromise and have a scene that has a bias of a pleasing kind rather than the ugly variety.

Correcting White Balance

The easiest way to make the adjustment in Lightroom or Adobe Camera Raw is with the White Balance tool.  It looks like an eye dropper. You click the tool, then click a gray area of the photo – if there is something that should be gray in the photo, that is. Even a white area is fine (but not an overexposed white). Stars are generally not good choices for gray-scale selection both because they are often over exposed and because many of them are NOT white! In the example below you see a photo of the Ocracoke Lighthouse which is definitely white, not the orange that resulted from sodium vapor lights.

LR_WhiteBalanceExample

The White Balance tool in Adobe Lightroom

ACR_WBtool

Adobe Camera Raw White Balance Tool

The dubious result of getting the lighthouse to its proper color via the white balance tool appears below. The sky and stars are unnaturally and artificially blue.  There are several solutions to this problem: color correct the lighthouse separately or compromise by warming (increasing the temperature) of the selected balance. Or try again by clicking elsewhere!

LR_WhiteBalanceExample_After

By selecting a different location for the gray sample tool a better compromise can be achieved as shown in the photo below. An examination of the scene reveals that the lighthouse is directly lit while the shed (near the bottom of the shot) is not. The shed and other areas in shadow are lit by ambient light reflected from many sources – including sky glow. After selecting the shadow area the remaining white imbalance of the lighthouse can be handled by desaturating using the local adjustment brush – or leave it like it is.

LR_WB_ChoiceB

 

White Balance Correction in Photoshop

The same eyedropper style adjustment can be found in Photoshop, but you’ll have to hunt for it because the “Color Balance” Adjustment is not where you’ll find it!

PhotoshopWB_a

White Balance (gray point) selector of Curves in Photoshop

White Balance (gray point) selector of Curves in Photoshop. The gray point selector is also in the Levels adjustment.

Note that in Photoshop you have two ways to go: use an adjustment layer, or use an Image -> Adjustments -> Curves (or Levels). We recommend using an Adjustment Layer because you can paint on the mask to control the effect and that makes it easy to adjust different parts of the image separately.  To adjust areas separately in Lightroom, use the Local Correction brush and adjust the white balance slider.

Selective Color Balance Correction

Consider the following photo. With the new flight rules, you can use your camera while the plane is taking off or landing.  Here the plane is landing at San Jose International Airport. There are two things about it that are good candidates for fixing. The first is the distracting glare of reflection from light inside the airplane (that’s due to Virgin America’s “Purple Ambiance”).  We’d like to get rid of the distraction and it’s clear we will not be able to simply crop it out without giving up some of the interesting details.

Landing

Glare from internal reflections leaves a blue cast. There is also noise in this one second, ISO 1600 exposure.

The second thing that is noticeable in the 100% (Zoomed view) is the colorful noise in the dark (and light) areas of the photo.  No sky has grit in it – at least not like that!

gs_2014-01-28_085553

100% View of the noise near the wing.

We can tackle both problems separately or at once.  Selectively desaturating, and slightly darkening the blue glare is simple in Lightroom.  Select the adjustment brush (it looks like a face powder brush right below the “Histogram”), dial down the saturation, and slightly dial back the exposure. Then paint on the image where we want the change to occur.  It may be useful to adjust the brush size, density and feathering. Here some feathering is important. We will not try to also increase the noise processing here, because the whole image needs some despeckling.

Below the mask shows where we painted – and not particularly carefully, either!  The Saturation was turned down to -69, and the exposure by almost a full stop. In a brighter sky we might not have been able to darken the touched up area as aggressively.

Attacking the Glare with Local Adjustments in Lightroom

Attacking the Glare with Local Adjustments in Lightroom

The next thing we want to address is the noise. It’s everywhere in this photo. As we will learn in the next article, we often use noise reduction for smoothing things like blue (or dark) skies and in shadows where you would not expect to find details.  Using Adobe Camera Raw for saturation, exposure and noise reduction works the same way as in Lightroom it’s just that the adjustment brush is shaped differently and found in a different place.

The adjustment brush in Adobe Camera Raw

The adjustment brush in Adobe Camera Raw

Out Darn Noise

In Lightroom (and Adobe Camera Raw), there are two simple – and effective ways – to reduce noise in photos. One is to selectively reduce noise using the “Noise” slider of the adjustment brush as we saw with our selective saturation adjustment. Moving the Noise slider to the right increases the amount of noise reduction but does not give you control over what KIND of noise reduction is performed. ACR and Lightroom have specific controls to reduce Luminance noise (dark and light speckles) and Color or Chroma noise (colored speckles). The noise reduction slider with the Local Correction brush does not let you control which type of noise reduction is applied. Sometimes correcting only the luminance noise is the best approach.  Both methods of correcting noise result in some blurring of the photo. How much blurring depends on how severely the sliders are adjusted. There is no formula for getting noise reduction to work well except to be careful not to over do it!  Surprisingly, a little bit of noise makes a better photo. Indeed, there is an option to ADD noise in the “Effects” panel (called Grain). One thing to beware of: using the color noise reduction aggressively will result in loss of star colors in your night sky. In the examples below we’ve brightened the image to make the changes easier to see.

Before any Adjustment

Before any Adjustment, Turning off the default sharpness enhancement.

The noise reduction portion of Lightroom is found in the Details section. Any controls used in this section will apply to the entire image – which is one reason adjustments should be made carefully and deliberately.  The first step we usually take is to eliminate the default sharpening that Lightroom wants to apply.  We would rather selectively sharpen what needs sharpening than doing indiscriminate global sharpening. Next zoom in to 1:1 view of an area (Z key) where noise reduction is needed. For this pick a dark area where some details should be observable. It is also helpful to pick a dark area adjacent to a lighter area where sharpness is desired so the effect of noise reduction can be seen on two elements at once.

We slowly bump up the luminance until we see less “grit”.  Be sure to wait long enough to see the changes made in the image.  We do not generally notice much difference with the detail and contrast sliders, but if we find ourselves adjusting as far as halfway on luminance and not getting what we want, we play with those sub-sliders.

If we still have not achieved the correction we want, we bump the color slider as well… only much more carefully. If there is a LOT of color noise the color noise correction may be the slider to bump first.  Once things are “almost” where we think they look right we choose another area to take a look. It  is important to select an area of the photo that did not need much adjustment – usually a bright area. If the brighter area has become too blurred, we back off on the overall adjustment and then use a local adjustment to add still more noise reduction selectively.

All adjustments made - note that perfect smoothness is not a goal.

All adjustments made – note that perfect smoothness is not the goal!

In Photoshop there are many more ways to reduce noise than those provided in Lightroom and Adobe Camera Raw. Our experience is that the noise controls in ACR and Lightroom are very good – better than any specific filters you will find in Photoshop.  We do use Topaz Lab’s DeNoise photoshop plugin quite a lot however.  The best noise reduction method – when possible is to use the Simple Astrophotography Processing Technique. A photo like the one shown here is not a candidate, however, because that Astro technique requires multiple frames of the same image – that wasn’t possible here with the aircraft coming in for its bumpy landing.

Finished Image

Finished Image

In the next article we will take on the remaining subjects, but you may have already figured out one of the techniques we use for desharpening – aggressive noise reduction!

Color Is Powerful

You know that color has power. All I know is that in my attempts to render the night sky, some images work better than others – and usually the difference is in the color.

For example, this image was runner-up in the Astronomy Photographer of the Year competition:

Lost in Yosemite [C_033706]  Runner Up - Astronomy Photographer of the Year, 2012

But I also produced an image where the sky is less green and more natural:

The former image is nearly exactly the way the camera chose the colors. To me (and others who I asked) the first image holds more drama which is entirely proper since the two tiny figures were quite literally lost in the wilderness when we found them.  The bluer second image seems more tranquil.

Night images are notoriously difficult to make authentic looking. The camera sees colors I cannot see – like blue and brown in the sky at night. My vision (and yours) is severely curtailed in low light. The camera reveals that in a dark sky there are indeed blues and browns. The camera, however can get confused because it does not know what color white is!  Sometimes the camera’s guess at a proper white balance is interesting and pleasing.

Famous III [C_035478]

Often, however cameras make a poor choice and produce a dull image.  Our brains do a much better job of deciding what colors make sense. And since it is we humans who notice the nuances of color it is entirely proper that we should exercise the right to override the camera. In the photo below the combination of sodium vapor streetlights on the foreground and tungsten-halogen floodlights on the rocks left the camera with no good choices. However when I chose the color on the rocks to be the white standard I was able to get  an accurate and pleasing – if somewhat surreal – result.

On the Edge of Surreal

 

Here are some ways the camera might record the same scene:

What Color is White?

Clearly if left to its own algorithms the camera’s white balance choice could range anywhere from awesome to awful.

The message here is two-fold: be conscious of the white balance the camera chooses but do not be a slave to the camera choice. The camera doesn’t see the way you do!

Milky Way Post Processing: Color Correction

I’m sure you did not skip the first two parts of this series, right? Did you? If so, please see Finding the Milky Way and Capturing the Milky Way. I’ll wait until you get back.

Back so soon? Hope you had fun reading about the Milky Way and how to photograph it. Here is a confession: You really do not need to jack your ISO up as far as I stated in Capturing the Milky Way. What happens when you set the ISO high is that you lose some dynamic range, and you will get some clipping (loss of highlights), and of course you increase the noise – BUT your processing will be a little easier because you won’t have to push any settings more than just a smidgen.

Hear are the general steps I take to attack my Milky Way images.

  • Noise Reduce
  • Color Correct
  • Contrast and local enhancements
  • Foreground/background blending

There are dozens of ways to do each of these tasks.  If you love Lightroom (I don’t particularly like it because it is SO slow to load and doesn’t allow me to blend multiple images) you will find some great resources by Ben Canales. For a $20 donation he’ll walk you step by step through his processing regimen.  The only downside to his tutorial is you must have web-access to view it – you can’t save a copy.

Even though I would normally noise reduce first, I am deferring the explanation for now and attacking the color balance problem. Sometimes all you need to properly color correct is to open your image in Adobe Camera Raw and use the White Balance Tool.

Much of the area near the Milky Way is “white” so clicking that diffuse glowing part with the white balance tool will properly balance your sky… or not depending on how bad the light pollution is.  Where exactly should you click? Not on individual stars (though that may work too if you pick the right colored star and you do not have clipping).  Just about anywhere except the brightest areas of the Milky Way should work.  It will not hurt at all to “click around” a bit until you get a natural look.  Here is a Milky Way image color corrected using the ACR white balance technique:

Milky Way Rest [C_049455]

However if the light pollution is pretty bad, you don’t have a raw file or your sky is quite orange/brown, you will want to employ a more potent solution.  This solution comes from Sky at Night Magazine.  Below is a video we recorded during our Photo Manipulation 150 Webinar.  One giveaway that your sky is not naturally colored is if it is orange, brown, green or completely blue.  I am not going to tell you not to render your sky like that – after all it is your photo and your taste will dictate what you want, but if you want people who enjoy astronomy to take your photo seriously do not go too far from reality.

One of my favorite images of the Milky Way resulted from allowing the camera to select a white balance. I used a blue-white LED flashlight and that caused the night sky to go “sepia”.  I did do some local enhancements to bring out the Milky Way. How I did the enhancement will be discussed in the next installment covering “Local Enhancement”.

Famous III  [C_035478]

If, however you want to get your sky naturally colored despite the light pollution, hopefully you’ll find this video informative – there are a bunch of additional tips, too!

You may have to enter the password BrownSky to watch it.

RESOURCES:

Related Articles Include

  1. Local Enhancement (Bump up Those Stars)
  2. Image Blending (Foreground O MaticEasy HDR)

Are we getting this right? Got a question? A quibble? Please leave a comment! And if this is really resonating with you, please share.  We love it when you share.

Stacker’s Checklist

Created November 2, 2010
Last Updated April 19, 2019

Note: Items in RED are suggestions that apply in particular to star trail captures and may be changed based on circumstances at the scene and goals.

Site Selection

  • Sunrise, Sunset, Moonrise, Moonset and moon phase all known.
  • Safe area, travel paths known

Equipment

  • Camera, tripod, release plate, camera batteries, memory card, lens, intervalometer + batteries, lens hood, rain protection, headlamp, flashlight/torch, and items for light painting.

On Site

  • Tripod set up – no leaning (center column should be vertical) – leg locks tightened.
  • Camera aimed, leveled.
  • Camera locked onto tripod. Head tightened.
  • Tripod weighted/secure and everything is wobble free. Keep the tripod low and out of the wind for best stability. Do not extend the center column.
  • Neck strap removed or secured to prevent wind throw. Intervalometer and any other cord, or wiring also secure. Velcro on the intervalometer and the tripod leg is a handy trick.
  • Save GPS coordinates and/or mark site with glow stick / other?

Camera Settings

  • Manual Mode, Bulb exposure
  • ISO 200  (varies but from 100 to 800, and up to 6400 if capturing meteors or the Milky Way)
  • Single Exposure
  • LCD brightness down
  • Image review time off
  • Record in RAW
  • White Balance = daylight (Auto not recommended)
  • Aperture f/4 (f/1.4 to f/7.1)
  • Auto focus OFF
  • Image stabilizer (vibration reduction) OFF
  • Long Exposure Noise Reduction OFF
  • Mirror Lockup OFF
  • Auto Exposure Bracketing OFF
  • Focus Assist OFF (this often fires an infra-red beam/red beam and will annoy other photographers). On many cameras this feature is on the flash unit/speedlite. On Nikons, this resource may help.

Timer Setup & Test

  • No delay, length of exposure = 1:59 minutes (adjust based on conditions. A 2 minute total interval is a good starting point), interval = 1 second, Num exposures >= 120
  • Timer cabled to camera
  • Test sequence (lens cap on) – Verify that second shot starts before canceling.

Focus & Final Framing

  • Check image composition, field of view.
  • Set camera to Aperture priority mode (not needed if it is already dark)
  • Take several bracketed shots in daylight or twilight: if it is already dark take a high ISO “range finding” shot. E.g. 2000 ISO for 30 seconds.
  • Pixel peep and adjust focus until sharp.

Battery and Card Shuffle

  • Remove memory card and insert second card. Format new card in camera.
  • Take second set of bracketed shots.
  • Return camera to Manual/Bulb mode.
  • Turn off camera and remove battery.
  • Reinsert battery (or insert fresh battery).
  • Verify that all settings are correct (See Camera Settings, above)

Final Steps

  • Check for wobble. Start by lightly jostling the camera, tripod, center column and even walking around in the area to make sure no movement occurs.
  • Set DELAY on interval timer appropriately (at least 5 seconds).  Goal is to start and/or end in twilight.
  • Secure cables for timer, external batteries (and neck strap). Do not block battery or memory card access.
  • Switch to aperture priority mode (so that your manual settings do not change), take a single image and re-verify focus. If already dark, take a high-ISO range finding shot for this task.
  • Switch back to Manual/Bulb.
  • Verify all camera settings as described in Camera Settings
  • Start Timer and verify that the timer is running.
  • If practical wait for first two shots to complete.
  • NOTE: You can leave the lens cap on for the first few exposure to collect DARK frames.

My thanks to Mike W. for comments and improvements to this checklist.

Additional References