Tag Archives: White Balance

Color Is Powerful

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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.

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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.

Steven Christenson: Vertical &emdash; Famous - Ancient Bristlecone and Ancient Light

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.

Steven Christenson: New &emdash; 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

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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 give away 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 of “Milky Way Post Processing: 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:

Coming Next

  1. Noise Reduction
  2. Local Enhancement
  3. Image Blending

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

Aside

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Note: Items in RED are suggestions and may be changed based on circumstances at the scene.

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)
  • Single Exposure
  • LCD brightness down
  • Image review time off
  • Record in RAW
  • White Balance = daylight (Auto not recommended)
  • Aperture f/4 (f/2.8 to f/7.1)
  • Auto focus OFF
  • Image stabilizer (vibration reduction) OFF
  • Long Exposure Noise Reduction OFF
  • Mirror Lockup OFF
  • Auto Exposure Bracketing OFF

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

  • 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