Tag Archives: Lightroom

Stacking: the Overloaded Word That Needs Explanation

The current rage of “stacked Milky Way” (or night sky) captures is quite different from the star trail or timestacks style of captures. Huh? The words stack and stacking are overloaded with many different meanings. Let’s see if we can add some precision and clarification.

Here are some of the variations possible:

  • Auto Blend Layers with Stacking: Used for macro/focus stacking, HDR, and generic image blending – NOT for astro images!
  • Lighten Mode Stacking: Creating Star Trails!
  • Statistics Mode Blending (Stacking): Can perform the same operation as Lighten Mode Stacking when the option “Maximum” is used, however Statistics are heavy weight and more complicated to do in our opinion.
  • Align and Stack: Deep sky astrophotography using several images taken one after another as quickly as possible. Photoshop doesn’t do this well, but we describe how in the next section. Align is the distinguishing word here.
  • Tracked Stacked Images: For still astrophotography images with less noise and greater detail. A device is required that tracks the sky rotation – the word tracked is the key here.

    Adobe Lightroom and Adobe Bridge “Stacking”

  • Group into Stack:  Not stacking at all! It really just means “create a group”.

The above is NOT an exhaustive list of the kinds of stacking you may hear about!

Stacking Types Explained

Group into Stack

Let’s start with the easy one: Stacking may mean add to group. In Lightroom and Adobe Bridge you can pick several photos and the options  Stacking -> Group into Stack. Or pick several photos and either Photo Merge to HDR or Panorama with the “Create Stack” option checked. In this context, Stacking and Stack just means group.  Unfortunately a photo can only appear in one stack, and you cannot stack photos from different folders together.

Why would you want a photo to appear in two (or more) stacks groups? Here is an example where I used a single top shot and created two different panoramas.

Panoramas 1 and 2 were both created using image 3 (608095.NEF) but when panorama 2 was created, image 3 was removed from the stack (group) for 1 and added to the stack (group) with 2. Furthermore, you can see that the panorama and the two photos used to create it were all added into the group (notice the last image says 3 of 3).

Blend Layers using Lighten Mode

Stacking may mean blend photos in lighten or darken blend mode – examples are star trails and timestacks. In this usage, the lightest (or darkest) of all the pixels in each image is selected. This is the kind of stacking that AdvancedStacker Plus does. Below is an example of taking several images that we collected over time with long delays between each exposure causing the “dotted” appearance of the star trail.

Several layers of images taken at intervals all set to blend mode “Lighten”

Align and Blend Stacking

Stacking can ALSO mean ALIGN and blend images with median, mean (aka average) or more sophisticated algorithms. Indeed astroimagers have been doing this style of blending for years using techniques that involve “star registration” (aligning stars with stars) and some pretty fancy stacking algorithms like Alpha-Kappa Median Clipping and Entropy Weighted Average. The key point here is the alignment. Indeed, here at StarCircleAcademy, we’ve explained how you can brighten and reduce noise in your foreground using simple astrophotography processing techniques.  See below for how to accomplish Align and Blend Stacking in Photoshop, and plenty of warnings about why this method is very likely to FAIL using Photoshop as the tool.

You may also see references to tracked, stacked images. These are the same as “align and blend” just described, except that to capture the image, the camera is guided by an external device (or by some fancy internal hardware), to allow longer exposures of the stars without getting unintentional trailing (smears) of stars.

The takeaway is that not all stacking is created equal. You need to know the context to understand what is meant by the word: stacking.

Focus Stacking / Auto Blend Layers

In Photoshop there is Edit -> Auto-Blend Layers -> Stack Images this is yet another kind of stacking (focus stacking) and despite the wording is NOT the kind of operation needed to ALIGN and Blend astro images. If you don’t believe us, give it a try and you’ll see it will do very weird things with your layers. Below are the same images as earlier. Note the bizarre masks it created to do the blending.

Edit -> Auto-Blend Layers -> Stack Images makes a mess. We told you so! Click to see a bigger image.


Aligned, Stacked Starry Landscape Images

While it would probably be better to make this a separate article in itself, we found it painful enough that we don’t recommend bothering – and yet we proceed to explain HOW to do it anyway!

If you want the cleanest possible images, you’ll – of course – want to reduce the overall noise  and bring out details by using many images instead of one. This approach is not all puppies and kittens. Here are some of the pitfalls:

  1. The direction of sky movement relative to the ground has a significant influence on the quality of the result (as well as the order chosen for alignment). In general, setting constellations are better than rising ones.
  2. Most of the existing tutorials will assume that you have a recent (CC) version of Photoshop with statistics and an an “Auto Align” that properly manages masked regions.
  3. Some of the tutorials we’ve observed are more cumbersome than they need be. There are plenty of hotkeys and mouse shortcuts to make the process go pretty quickly.
  4. More than 10 or so images can become quite demanding on machine resources.
  5. The complexity of your foreground will also affect the outcome. A clean, crisp separation between sky and land is preferable. Trees, poles, wires, and other things that extend through the sky are problematic.
  6. Lens distortion can also adversely affect the outcome.

Aligned Stacking Procedure

  1. Load all the photos as layers in Photoshop.
  2. Heal out airplane and satellite trails from each layer.
  3. Select all the layers and add to a group named “Sky
  4. Right click the Sky Group and duplicate the whole group as “Foreground”
  5. Select all the layers in Foreground.  Use Layer -> Smart Object -> Convert to Smart Object.
  6. Select Layer -> Smart Object -> Stack Mode -> Mean
  7. Duplicate Mean using Ctl-Alt-Shift-E (Command-Option-Shift-E on MAC). Label the newly created layer “Mean” and turn it off.
  8. Select all layers in Sky. Set blend mode to “Lighten” and observe the direction of star movement against the ground.
  9. Be sure the image with stars nearest the ground is at the BOTTOM of the stack. The bottom layer will be your base for alignment. You can drag layers around, or Layer -> Arrange -> Reverse may do the trick.
  10. Create a mask keeping as much of the sky as is easy to do but that DOESN’T include any ground  or fixed location objects. IMPORTANT: Be sure the mask doesn’t have holes in it, including at the bottom corners. Click the layer mask, hold down the Alt (Option) key and drag the mask to the next sky layer. Repeat until all sky images are masked with the same mask.
  11. Select the bottom layer and lock it  (Layers -> Lock Layers -> check Position -> Ok)
  12. Select all the sky layers.
  13. Chose Edit -> Auto Align Layers -> Auto
  14. When alignment is done, set blend mode for all sky layers to Darken. If stars are disappearing in the result image, that’s bad.
    1. If alignment is great everywhere, that is you have plenty of stars, you’re done. But it probably won’t be. So…
    2. Duplicate the current layers to a NEW document – call it whatever you want, but perhaps “Left looks good” makes sense.
    3. Open the history palette and click just above the “Align Layers” item (to restore to before the alignment was done). Lock the TOP layer (see item 11) and repeat steps 12-14.
    4. If a large portion of the image still has streaks in some quadrant, try undoing align, undoing the lock and re-aligning.
    5. If you’re still getting a significant amount of streaking you can also try Auto Align -> Reposition rather than auto.

      Q: Why do I have disappearing stars?
      A: The reason they are disappearing is because they are not aligned. In Darken mode, the darker sky “wins” out over the several stars. This COULD be a good thing in other situations, but not here!

      Q: If I went through the trouble of doing all this alignment, why is it still “off”?
      A: Photoshop isn’t optimized to align stars. Secondly, lens distortion makes a star move non-uniformly across the sensor. And third: stars at different declinations (celestial latitudes) travel at different speeds across the field. To eliminate streaks, the best solution is to track the sky.


  15. Take the aligned sky, delete all the layer masks. With all the aligned sky layers selected, create a smart Object.
  16. Do the same Stack Mode “Mean” trick for the sky smart object that you previously did for the foreground.
  17. The rest is pretty straight forward. Turn the foreground (mean) back on. Use a selection to reveal only the foreground and apply that to the Foreground Group.
  18. Adjust contrast, color balance, vibrance, etc. to your satisfaction.
  19. Save the kit and caboodle.

Does all this seem too complicated? Well, then perhaps you might consider using these tools instead. They do most of the hard work for you and they KNOW the difference between stars and foreground (usually because you help them know).

  • On a Mac: Starry Landscape Stacker – from the Mac App Store
  • On a PC: Sequator – do a Google Search to download it.

By the way there are many astro processing tools, like Deep Sky Stacker – but most/all of them expect that your images will have NO foreground or non-moving objects like wires in them.

Lickety Stitcher in Lightroom + Panoramas IN Lightroom

Published: November 15, 2017

Pointyland Redux

A conventional panorama stitched with Microsoft Image Composite Editor from 3 images.

Maybe we should start by explaining Lickety Split. Lickety Split is US English slang for fast so “Lickety Stitcher” is our contrived slang for a fast image stitcher. Image stitching is what you do to create a large image out of several smaller, overlapping images.

We’ve reported how much we like the FREE Microsoft Image Composite Editor (aka ICE) for stitching images because it is faster and more accurate than Photoshop’s Photomerge or Lightroom’s new, but sometimes anemic Photomerge. Here is a simple “quick panorama” method of creating a panorama from about 3 clicks. How? Configure Lightroom to run ICE as an export step. After creating the export step (described below) you do the following:

  1. Select photos,
  2. right click “Export -> ICE Quick Stitch”
  3. Click through the ICE Menus to Stitch, crop and Save.

Sadly, there is no Image Composite Editor for Mac computers. If someone knows of an equally easy to use, fast version for the Mac, let us know in the comments!

How To Set Up Lickety Stitcher

To use Microsoft ICE (or PT GUI, or other external tool), you create an Export setting for it. Click a photo (any photo), then “Export” and Add new settings as shown below. The only tricky part is finding the program you want Lightroom to run. In Windows it has to be the actual path, not a shortcut.

Microsoft ICE Panoramas from Lightroom

You don’t have to settle for only a “quick stitch” (which is best done with JPGs), you can also export full sized TIFF files and stitch those.  ICE can save documents in Photoshop .psd format and others. And if you have another image stitcher you really like, e.g. PT GUI, you can probably use this same trick to make that software work on demand.

What About Lightroom for Stitching?

We were happy to discover that Lightroom and Photoshop image stitching (panorama) creation has improved quite a lot since our first disasters trying to do vertoramas and panoramas. Indeed, I think we would be happy to use the new tools and skip using ICE in many circumstances. Here is how you use the Panorama creation feature of Lightroom.

First, pick your images. They should overlap by at least 1/3 from frame to frame. And you can pre-process them with noise removal and such. Highly recommend you do at least two things to images before you try to stitch them:

  • Use vignette correction appropriate for your lens.
  • Consider using Distortion correction before creating your panorama – not always necessary.

Then right click and find “Photo Merge -> Panorama”.

Lightroom did a quite respectable job. We were able to to create the image below entirely in Lightroom. We did see some problems, however:

  1. We got a message about “unable to save metadata”
  2. Lightroom insists on creating the image as a .dng file and uses the name of one of the files you picked (we’d like it to be a mash of first-through-last.
  3. Lightroom didn’t seem to be as smart as ICE in how it stitched the images. ICE joined the images without the airplane and satellite trails, or maybe it was just better at blending them out. We had to do that work by hand on the image Lightroom created. It was not difficult, though. It is not the first time we have seen ICE handle an image better than Photoshop PhotoMerge

In ICE we manually  bent the slightly arching shot back into vertical form and did manual cropping. In Lightroom we used the Boundary Warp option at the end to make the images fill the frame nicely. Here is what we got from those 11 images:

10 Image Panorama using Only Lightroom Photomerge

You can compare the above to the same images used via Microsoft ICE and finished in Photoshop.

Overarching Majesty

Stitched in ICE, Finished in Photoshop

Multi-Row Panorama

Here is a more ambitious 22 photo, multi-row panorama stitched with Microsoft ICE. There was a stitching problem due to cloud movement… maybe you’ve spotted it.

Asylum at the Sea

 

Stitching Software Alternatives to Photoshop, Lightroom and ICE

  • Hugin (FREE: mac, PC, Linux). Don’t much like this one even though it is free.
  • PTGUI (mac, PC). A little clunky, but does much more than stitching including HDR and can be automated. This is the one tool you need when you need to convince an image to stitch that just won’t do it. It can’t do miracles, but with work, it can get the job done.
  • Others… that we don’t have familiarity with, though we have heard good things about Kolor Autopano

Exploring Night Photography Lesson 5: Photo Processing

Published:  May 4, 2016
Last Update: May 10, 2016

Homework assignment: Star Trails. This was created using StarStax with 150 exposures of ISO 800, f/4, 15 seconds.

Homework assignment: Star Trails. This was created using StarStax with 270 exposures of ISO 800, f/4, 15 seconds. What are those things where the arrows are pointing, and what is the circled constellation?

Last week in lesson 4 the subject was star trails. We continue that theme this week and fill in with some material that you may have learned the hard way.

What settings?

Last week’s assignment was:

  • Weather Permitting, get at least 20 minutes worth of star trails. First determine what the best starting exposure is, then take 20 minutes worth.

I chose to take about 270, 15-second exposures at f/4, ISO 800 for my star trails using an intervalometer trick that I demonstrated in class. That nets over an hours worth of exposures. But how did I come up with those settings?  It was a little bit experience, and a little bit application of the principle taught in the very first homework: namely try and see!  But how did I decide what evening I would try to get star trails?  The weather needed to be right, so the germaine question is:

When will the weather be right for star trails?

Well, we strongly recommend weather.gov. See our article about how to use the information. Indeed, we like it so much, we even created a page with forecasts for places we often find ourselves going.

Weather, check. Settings, check. Now what?

Wait, what about the moon? We need to know when it rises and sets. A full moon washes out a lot of the night sky and makes for unpleasant star trails.  There are many places to determine what the moon situation is like, but I like to use The Photographer’s Ephemeris (either the App, or the online version).

Next we need to review the Stacker’s Checklist both to be sure we have all the gear and that we know what we are doing. Best is to run through it at home. Is it surprising that there are SO MANY steps? Sorry, but they are there to prevent you from making all the mistakes we’ve made.

In class we reviewed our homework (star trails) from the last assignment and discussed hits and misses.  Finally we got to the meat:

Photo Processing

It would be foolish to attempt to describe everything we did in class… especially since we have so many articles here describing how to photo process your shots (and webinars and recordings, too – oh my!)

But we demonstrated three things:

  1. Super simple Panorama creation using “Image Composite Editor” from Microsoft. Yep. You have to have a Windows machine to use it… but it’s free and SUPER simple and more effective than anything we’ve managed to get out of Photoshop or Lightroom.
  2. What Lightroom is good for… cataloging your images. And what it’s NOT good for: complex multi-image editing – for example star trails and image combinations.
  3. The three most powerful and useful elements of Photoshop:
    1.  Layers – This is the real meat of Photoshop together with blend modes which mathematically combine layers.
    2.  Masks – Masks allow you to change the way layers and adjustments get combined by “masking” out some of the changes.
    3.  Adjustments:  Curves – Curves are the best tool to learn since nearly everything you can do with the other tools can be done with curves… and if you get the hang of it, curves are actually easier to understand.

We also demonstrated Adobe Bridge which is a “lighter weight” version of Lightroom – one that doesn’t require any importing. And we spilled the beans that “Adobe Camera Raw” is the guts of Lightroom. And that Lightroom adjustments are really just like what you can do in Photoshop… with some of the magic, and much of the versatility – and also much of the complexity removed.

We also explained why RAW is the way to go, and why RAW is ugly (short reason: the camera does not see the way we do it just records heaps of numbers).

We did not do this in class, but we covered much of the ground:

12 Minute Star Trail using Advanced Stacker PLUS version14D from Steven Christenson on Vimeo.

 

Top Six Questions We Answered About Lightroom

  1.  If I use Lightroom to catalog and organize my images (keywords, etc) am I forever wedded to Lightroom?
    Practically, yes. We used to use Picasa and did our organizing and cataloging there…. unfortunately Picasa was discontinued and Lightroom had no way to import the data. If you stop paying for your Lightroom Cloud edition, you may be stuck as we do not know of a tool that can digest your Lightroom catalog.  SOLUTION: BUY Lightroom, don’t just subscribe. This is not so true about Photoshop, by the way, many tools can import Photoshop files.
  2. Is there anything particularly painful about Lightroom I should beware of?
    Yes. Lots! When your image library gets large, managing images is unwieldy, especially if you want to use multiple computers and multiple storage devices to hold those images.
  3. Is Lightroom good for Night Photography images?  Not particularly. Most of the power of manipulating night images is found in Photoshop (averaging, stacking, compositing). Lightroom can not composite images, for example.
  4. Is Lightroom hard to use? Yes. No. Maybe. We think it is powerful and much easier to use than Photoshop. But there is still lots of learning and ample room to do the wrong thing.
  5. Should I import everything I shoot?
    Yes… and No. The smaller the image library the easier it is to keep organized. Of course if you delete the very images you later want you will have paid a price for your anti-hoarding behavior.  We do believe it is reasonable to throw away .JPGs if you are keeping the RAW files. And those fringe images that you are likely to never use – well you are likely to never need them.
  6. Can I do everything in Photoshop that I can in Lightroom?  Yes, mostly. Photoshop has no image organization tools, but yes, you can make all the adjustments in Photoshop that you can do in Lightroom… only it will be harder to do and may be harder to apply to multiple images at once.

Oh, by the way, the official name of Lightroom is “Adobe Photoshop Lightroom” just to confuse everyone.

What Are the Top 4 Things to Know About Photoshop?

  1.  Photoshop is the lingua franca of photo editors. Nearly every other tool does not come close in the level of acceptance and use. Widespread use does not mean Photoshop is the best tool. Remember how VHS beat Beta? These days video tape is hardly even used! Photoshop has been around a long time and has a LOT of baggage. Photoshop is built to do a lot of things way beyond photo editing (scientific analysis, animation, typography to name a few). Because Photoshop has been around so long, the tooling is unnatural .  We started with Paint Shop Pro and found it much, much less confusing.
  2.  Is there an alternative to Photoshop?
    Yes, there is the free Gimp, and many others. Unfortunately as we have noted above, those tools are not as widely used so getting help with them is harder.
  3.  Do you have any suggestions on what I should learn first?
    Why yes, thanks for asking. We have a series of articles on that:  We call the series “The Most Used Image Editing Techniques” and it comes in three parts: Part 1, Part 2, and Part 3.  The one we used the most is the “Simple Astrophotography” Trick to reduce noise.  We also like this trick to select a foreground (it’s used in the video above) and use it a lot.

Homework Assignment

  •  Fire up Photoshop and try to duplicate this image:
Final image with replaced foreground

Final image with replaced foreground

Super big hint… all the files you need and the process to accomplish the task is described in this article: Foreground-o-Matic.

  • Use the same technique on your own image(s) to pick a more interesting foreground image from a “stack” (sequence) of images.

Feel free to comment below if you know the answers to the questions we asked in the first image above. We will reveal the answers in the next article.

The 5 Most Used Photo Enhancement Techniques – Part 2

You are back! Good. In the last article we talked about White Balance and Noise Reduction. As two of the five most useful tools in the arsenal of the night photographer.

In this article we will tackle two of the remaining items:

  • Exposure and Contrast enhancement
  • Sharpening (and de-sharpening)

Healing and cloning will be in Part 3.

While we have seem some fascinating composite and highly edited images our goal is usually to make a compelling photo. But we do like realism, too. So while we will show techniques that can be pushed to extremes to make gaudy Milky Ways, or super saturated star trails, we personally do not go there often.

Exposure and Contrast Enhancement

Below is the result we want to achieve.

640_4

Single Exposure with exposure and contrast adjustments, healing, cloning, selective blurring and sharpening.

But we will be starting with a single daylight exposure from the Outer Banks, North Carolina. When we shot the scene we shot a bracketed exposure at one-stop intervals. Before we look at the exposures, let’s look at the histograms from each of the three exposures

RodantheHistograms

Which one is the best image to start with to make our adjustments? Hint, it’s the one at the right. The +1 exposure has no loss of detail because nothing has been over exposed.  Here is the exposure.

+1 Exposure

+1 Exposure

The scene seems flat and lifeless – almost nothing like it looked to the eye, and not close to what we hope it will be. Part of the reason it looks so flat is that we have not done any adjustments to the original RAW file. If you shoot JPGs the curves and saturation adjustments are automatically applied so you might conclude that RAW images are a waste of time. That would be wrong. The truth is there is much room for improvement in the RAW images and much of the “good stuff” is lost when the camera applies the conversion to JPEG.

All of the histograms show decently exposed images. But it looks like even in the +1 image we still have some room left. That is, we could have exposed a bit more to get the whites all the way to the right.  All of our histograms show that we have no black (nothing at the left edge), and no white (content at the right edge).  An underexposed image might have richer color but it will suffer when we boost the exposure and contrast. The lighter exposure will suffer much less degradation. In fact, the act of reducing exposure deepens the saturation – we do not have to play with the saturation sliders at all!  Pleasing saturation shifts from adjusting exposure are one of the many good reasons why exposing to the right (ETTR) is an effective strategy.

Adjusting Exposure and Contrast – Lightroom Auto

There are many ways to adjust contrast and surprisingly the “Contrast” slider is not usually the most effective way. Using contrast alone often makes the lights too light and the darks too dark. One thing you can try is to use the “Auto” button. It sometimes works. In fact, for these images, it works pretty well with the +1 exposure, but not as well with the normal exposure.

The "Auto" feature of Lightroom under Basic settings

The “Auto” feature of Lightroom under Basic settings

Here is what Auto did for this image:

Lightroom Auto Adjustment

Lightroom Auto Adjustment

The histogram has been stretched and the image looks pretty good. Note that we’ve turned on the clipping indicators by clicking where the white arrows point. After Auto we found a few small spots where black level clipping has occurred as indicated by blue blobs which are circled in red above. No big deal. You can also see what Basic adjustments Lightroom made – exposure has been reduced by one stop, contrast +20, whites +62, blacks -50.  We now have an idea what the Basic adjustments can do. Auto almost never creates a good result when working with dark or night images.

Adjusting Exposure and Contrast – Lightroom Tone Curve

There is another way, and in our opinion, a more powerful way to adjust the exposure and contrast and that is using the Tone Curve. One reason we prefer this method is that it has an almost exact analog in Photoshop (Curves), as well as an almost identical behavior if using Adobe Camera RAW.

Lightroom Tone Curve

Lightroom Tone Curve

What we want to do is to darken the shadows and midtones and slightly lighten the bright areas without losing information – that is to adjust the exposure and contrast. The process is called “stretching the histogram”.  It’s pretty straight forward. Click points on the curve and drag up or down and left or right to create a new curve while paying attention to both the image and the resulting histogram.

Before and After Tone Curve Adjustment

Before and After Tone Curve Adjustment

Can you make these adjustments using Adobe Camera RAW? Yes! The controls are nearly identical.

This is now a good starting point to apply some additional pop, But what if you wanted to do this in Photoshop?

Photoshop Exposure and Contrast using Curves Adjustment Layer

Histogram Stretch using Photoshop

Histogram Stretch using Photoshop

The image above has brought out a bit of pink in the sky, but the dune is a little flat and a little dark. The good news is there is a way to give specific colors special attention – using what we call the “twiddle finger”. You click the hand icon, then pick an area of the image you would like to brighten or darken. The luminosity selected is shown on the graph, then you drag the mouse up or down.

Twiddle Hand curve adjustment

Before Twiddle Hand curve adjustment

 

After twiddling.

After twiddling upward a bit

The twiddling can be repeated. Beware, though, twiddling is global, not local. In general the tone curve should always be flat or upward as you move left to right otherwise you will be lightening dark areas to the point where they become lighter than adjacent light areas.  One way to improve your curve is to smooth the graph. Click the pencil icon then the icon below it (graph adjust), then click the graph (above the pencil).

After a bit more fiddling and twiddling we get what you see below. What more fiddling? Well, we like to add another adjustment curve and select the “Increased Contrast” option.  If things were close to good to start with, the curve might go too far, so adjusting the layer opacity downward is the solution.  In fact, we use the “Adjust contrast curve” so often that we created an action for it and assigned it its own hot key (F9).

640_2

Original Exposure Contrast Enhanced, Histogram Stretched, fully twiddled 🙂

Now we have quite a bit more drama, and much more contrast.  Where are the distractions? What leads your eye away from the interesting parts of the scene?  What are the interesting parts of the scene? Now is a good time to make note of the distractions, because soon we will conquer those.

In truth, we have one more thing to address in the exposure category. The sky is a bit too bright. The solution is to apply a gradient using either Adobe Camera RAW or Lightroom (it can be done in Photoshop but it is harder than it should be, and less convenient).

Graduated Skies – Lightroom

The graduated filter (M) is our friend for not only darkening the sky, but also making other adjustments. That you can make multiple adjustments simultaneously is one thing that sets it apart from the Photoshop methods. Here we have zoomed to 100% to show both a portion of the sky and the location of the graduated filter tool. Note that the sky is a bit “gritty”. We will fix that!

Graduated Filter tool and gritty sky

Graduated Filter tool and gritty sky at 100%

Our sky fix will illustrate one of our other techniques: selective sharpening – only in this case we will de-sharpen to remove the “grit” as follows.

Applying a Gradient to the Sky

Applying a Gradient to the Sky

We use a sky gradient so often that we created a pre-set for it.  The preset reduces exposure by -0.76, contrast by -17, saturation by -24, sharpness by -40, and noise by +100.  Those last two, decreasing sharpness and increasing noise processing result intentionally in blurring. In this case the exposure correction is a bit too strong, but that is easy to fix by bumping the exposure up a little (-0.51).

Let’s look at what this gradient did to our sky. Notice how the grit is just about gone.

gs_2014-02-08_122146

 

If you are thinking that applying a gradient to darken the sky is somehow dishonest, then please don’t use a graduated neutral density filter (GND) which does the same thing at image capture time – but a physical GND does so less elegantly!

Sharpening and Desharpening

We snuck in a trick to desharpen a mottled/gritty sky above, so please read that for one direction. In fact, we find that using noise reduction is often the most effective way to soften because the result – if not pushed to an extreme – is often more satisfying than using any other method. But some things need a little sharpening, like the eyes and hair of people, the boundaries between objects in a landscape.  When we want to do sharpening we never (ok, almost never) do global sharpening.  One reason we do not globally sharpen is it tends to make mottle things more mottled – like the gritty sky we showed earlier.  It seldom makes sense to sharpen clouds or things that are not sharp by their nature.

Indeed in our beach scene there is really nothing that demands sharpening, but all the same, we’ll apply a little bit at the sky/ground border – mostly to help the sea oats stand out a little more. It’s tempting to think that the Lightroom adjustment brush “sharpen” tool is the right one to use here, but often sharpen alone is not as effective. When sharpening is overused it creates odd artifacts. Often the more effective way to sharpen is to use a bit of “clarity” as well as sharpening. Clarity is a local contrast adjustment which has no analog in Photoshop. If you want to use clarity in Photoshop you must bounce over into Adobe Camera RAW. In Photoshop CC you can get a layer into ACR using the Filter -> Camera Raw Filter dialog. Lightroom and ACR are very similar, so lets show ACR here.

Adjustment Brush in Adobe Camera RAW

Adjustment Brush in Adobe Camera RAW

After setting all the adjustments to zero (easy in Lightroom, just double click on each item), we set the Clarity up (+15), and the Sharpness up (+6). Adjust the size, feathering, density and flow of the brush and paint along the horizon and through the grasses.  It’s always better to go a little at a time than to try to go all at once.  When done hit apply or Open.

In Photoshop we often take a completely different approach. Instead we duplicate the layer, label it “Sharpened” then sharpen (using the smart sharpen filter) or noise reduce the entire layer and then mask it all off. We then “paint back in” the areas we want a correction applied to using a white brush on the mask.

Wow. We’ve spent quite a lot of time talking about exposure enhancements and sharpening and desharpening, so spot removal (cloning, healing and cropping) will appear in part 3.