Tag Archives: color

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.

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!

Why your Streak is (probably) NOT a Meteor

Satellite or Meteor? [C_061879] So you took our advice or perhaps the advice of someone more clever than us and have captured a streaking bit of flaming cosmic stuff that some people call shooting stars. We do not want to rain on your parade, but let’s first get something straight: that flaming streak is more properly called a METEOR.  If it hit the ground, it’s a meteorITE.  If it in fact struck YOU, well you’re a lucky one!  No one in recorded history has ever been directly struck by a meteor EVER. We know what you’re thinking (really, we do). You’re thinking, but dudes: “What about the German boy who was hit in the hand, or the lady who had one bounce off her furniture and hit her in the leg or the man who suffered a broken finger when one crashed through his windshield and bounced off his steering wheel.” Sorry those were METEORITES apparently you weren’t paying attention when we explained the difference between meteors and meteorites.  Did anyone ever find a meteor on the ground? NO THEY DIDN’T… they found a meteorITE. Are we harping? Sorry.

Here is the sad news. You probably DID NOT catch a meteor (or meteorite) in your photo. Terribly sorry to tell you that. Go ahead, bring the photo and plop it in front of us. Claim what you want… but we are skeptics. Below are some things to rule out before we will conclude you have indeed caught a meteor.

Why Are We Such “Meteor Haters”

Hey, don’t put words in our mouth. We LOVE meteors. We just don’t believe you caught one. And here is why.

  1. Meteors move VERY, VERY fast across the sky and therefore across your image.
  2. Only exceptionally bright meteors throw out enough light in their rapid transit to even  register on your sensor or film.
  3. Just because you SAW a meteor occur in the direction your camera was pointing when  it was taking a picture doesn’t mean it registered.
  4. And it probably wasn’t a meteor.
  5. Besides, we think you’re wrong. So there.

Ok, so we admit to being a bit sour about it. After all, collectively we have shot about 20,000 (TWENTY THOUSAND) frames trying to catch meteors. And how many did we get? About 100.  We didn’t get so few just because we suck at it.

Below the Belt [5_020853] CARMAic Visitor from Cygnus [5_034154]
Dew Drop In [C_019416] Chiplet [C_034134]

Perseus slays Little Bear, oh my! [B_032691]

Of those 100, about 20 are readily noticeable. Of those 20, perhaps 10 are well captured. And of those 10, sigh, only a few really stand out.   But perhaps we should admit that we – like you – didn’t make all of those attempts under the best conditions. No, Like you, we took most of our shots when there was moonlight, light pollution, streetlights, and other impediments and the result was as you see at the left here: the meteor is almost impossible to see.  Like you we’ve SEEN a lot of meteors. And like you, most of the time the meteor we saw was regrettably not where we had pointed our cameras.  It’s a game of (very low) odds, after all.

Why You Didn’t Catch a Meteor (or maybe you DID!)

So many times we have seen people post their “brilliant meteor shot”. Almost exactly as many times we noticed one or more of the following:

  1. There are tell-tale flashing white, green or red lights. The tale those lights are telling is “aircraft” but the gleeful meteor hunters have their fingers in their ears.  Look closely at your shot to see.
  2. The streak bends or changes direction and the curvature is not due to field warp (as with e.g. a fish-eye lens). Sorry, but only airplanes curve like that.
  3. The shot immediately before or the shot immediately after the prize has the continuation of the streak. There is a 0.000008% chance of capturing a single meteor that spans more than one frame.
  4. The shot was at low ISO (less than 400), a high f/stop (anything above f/4), a narrow field of view or for a very long time. For a meteor to register you’d need a super slow flaming fireball of a meteor. If in fact you got one, well good for you and we are jealous.
  5. After ruling out aircraft, most people fail to rule out the next most obvious possibilities: satellites, flare and moths.   Yep, moths or any other bug that might fly through a source of illumination. We’re pretty sure you’ll be able to tell if it was a firefly though. Satellites are a little sneakier. They can – and do appear, move through the sky and disappear.  And they can fade in and out, too.

Satellites

There are MANY satellites in the sky. So many that we catch them ALL the time.  About every shot that doesn’t have a stinkin’ airplane seems to have a bloomin’ satellite in it.  Most satellites are quite dim and you don’t see them easily with the naked eye, however there are a few bright ones and one family of satellites that is EXTREMELY bright for a brief time.  We’ll get to that in a minute.

Meteors and Meteorites Have A Signature

Star Man and Perseus [C_059960-1]

Perseid Meteor, Milky Way and Galen’s Arch, Alabama Hills, Lone Pine, California, August, 2012

Most meteor streaks have the following things in common:

  • They brighten rapidly and dim a bit more slowly.
  • They are asymmetric (the brightening phase and dimming phase rarely look exactly alike)
  • Because of the two things above, meteors streaks rarely, VERY rarely have nice round ends – generally one or both ends are tapered.
  • Often meteors are colored!  The Perseids, for example, are often green, the Orionids are often yellow.

Perseid meteor traveling from the lower left to upper right. Note the changes in brightness and color

About those Bright Satellites

Satellites seem to wink in and wink out because they are illuminated by sunlight.  You’ll rarely see a satellite at the (true) midnight hour because the earth prevents sunlight from striking the satellite. However for as much as 3 to 5 hours after sunset or before sunrise (and more at other elevations), a satellite may move quickly and stealthily out of the earth’s shadow into a place where it can be seen clearly against the dark sky.  Or it might do the opposite: streak across the sky and then wink out when it enters the earth’s shadow. But there is one spectacularly bright satellite. Sorry did we say one, we meant 90 of them!  The family of satellites named Iridium. The name Iridium refers to the planned 77 communication satellites – the atomic number for Iridium is, 77.  The Iridium satellites exist to service those big, bulky sat phones – about the only option you’ve got if you need phone service in the Bering Sea or on an ice shelf in Antarctica.

Satellite Flash (Iridium) [5_033852-4br]

Iridium and “Flares”

Because the Iridium satellites are highly polished, and because each of those 90 objects are circling the earth every 100 minutes or so at a relatively low orbit, it’s not at all unlikely that one will reflect the light of the sun toward you! If you happen to be in just the right spot the brightness is extreme.  How extreme? Astronomers use a stellar magnitude scale. On this scale the smaller the number, the brighter. The stars in the Big Dipper are around 3, the brightest star, Sirius, is -1.46; Venus, the brightest planet at its shiniest is -4.6 and the brightest Iridium flares are -9!  What this means is: Iridium flares can be more than 20 times brighter than Venus or about 400 times brighter than the brightest stars!

Iridium satellites move swiftly but nowhere near as fast as meteors so they are far more likely to leave a mark in your photo than a meteor. Iridium flares behave very predictably. They start dim, slowly grow brighter and then slowly fade all the while that they transit the sky. If you want to mess with someone, use an Iridium sighting tool, figure out when and where to look in the sky and tell people nearby: “I have this sense… that something strange is about to happen… right … up … there”.  If you time it well people will be so amazed they may fall down and worship you. Time it wrong and they will laugh. Either way it’s great fun.  [NOTE: That link will only work in MILPITAS, CA – you need to use your GPS location].

The thing is, however that your camera doesn’t know when the grand entrance is going to happen and it will dutifully record the event while you’re busy chatting with your fellow night denizens.

Meteor Radiant Point (Delta Aquarid Meteor Shower)
Unfortunately we ran out of space before we got a chance to explain to you that even your correctly identified meteor is probably incorrectly identified as a “Perseid Meteor”.

In summary, we TOLD YOU you didn’t catch a meteor!

But if you think you did and are willing to stand some public humiliation at being proved wrong, please post ONE alleged meteor shot below in the comments.  Please also give us the date, time, timezone and GPS location so we can make sure it wasn’t an Iridium Flare. Wait, why make us do that… do it yourself! The exposure information is important, too (length, f/stop, ISO, focal length).

Oh, one last thing… did you find this article interesting? Amusing? Alienating as hell?  Please share it!

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.