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Author Topic: White --> Blue Sky?  (Read 9563 times)

novice9

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White --> Blue Sky?
« on: November 01, 2009, 09:46:32 am »

I realize this is probably a pretty basic question, but here goes.

I have been shooting landscapes and getting alot of pure white skies that I would like to make dark blue in post processing, but can't seem to make that happen in either Capture One Pro or LR 2.5 (or 3.0 Beta).  Is that possible in either of those tools?  If so, how?  If not, what tool do I need?  Thanks much!
« Last Edit: November 01, 2009, 09:47:40 am by novice9 »
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Mark D Segal

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White --> Blue Sky?
« Reply #1 on: November 01, 2009, 10:12:09 am »

If your skies are coming out pure white when they were not in the original scene you have most likely over-exposed your images. Open any one of them in the raw converter (are you shooting raw?) or in Photoshop if you are not, and look at the histogram. If you see a spike climbing the right-hand wall of the histogram box, you have clipped (blown) channels and that is a sure sign of over-exposure. If all three channels are clipped you cannot recover the sky from internal data in Lightroom or Camers Raw. But if you can get a clean selection of the sky you can import or invent colour information to build a blue sky from scratch.
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Mark D Segal (formerly MarkDS)
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thierrylegros396

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White --> Blue Sky?
« Reply #2 on: November 01, 2009, 12:24:02 pm »

There is a tutorial in this website to solve the problem !

http://www.luminous-landscape.com/tutorial...sky_blues.shtml

Thierry
« Last Edit: November 01, 2009, 12:46:47 pm by thierrylegros396 »
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jdemott

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White --> Blue Sky?
« Reply #3 on: November 01, 2009, 12:29:43 pm »

If your photos are significantly over-exposed for the sky area, then there isn't a good way to make the skies blue in a raw converter like Lightroom.  A quick way to check in Lightroom is simply to reduce the exposure slider greatly  and see if the sky remains white or if it becomes blue.  If it turns blue, then you can fix the shot in Lightroom by applying the reduced exposure setting to the area of the sky (but not the rest of the image) with the Graduated Flter or Adjustment Brush tools.  If the shot is so over-exposed that reducing the exposure setting in Lightroom will not turn the sky blue, then the usual way of correcting it is to blend in a blue sky from another photo using Adobe Photoshop.  Basically you need to find another shot that has a sky that will look good in the over-exposed shot and put the blue sky on a separate layer over the over-exposed shot and then blend the blue sky into the shot using the blending options for the sky layer so that you see the sky layer only in the formerly white area of the image.

Skies can easily become over-exposed because the sky is often so bright that a correct exposure setting for the foreground will result in an over-exposed sky.  If you have Adobe Photoshop, you can take two separate exposures of the scene with the aim of blending them as I mention above.  Or you can use a graduated neutral density filter on your camera so that the area of the sky is darkened while the foreground is exposed normally.
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John DeMott

novice9

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White --> Blue Sky?
« Reply #4 on: November 01, 2009, 01:01:04 pm »

Thanks all for the excellent guidance.  These are indeed generally blown highlights.  As a follow on question, I am also wondering if there is a tool that allows you to define a portion of capture based on the existing color scheme and then assign a totally different color to it.  For example, if I were to take a photo of a red apple against a white background with nothing else whatsoever in the photo, and lets say i wanted to pick the red of the apple and assign a totally different color to it, say make the apple green or yellow instead.  Is there such a tool that allow such an operation?  thanks!
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jdemott

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White --> Blue Sky?
« Reply #5 on: November 01, 2009, 02:26:43 pm »

Quote
I am also wondering if there is a tool that allows you to define a portion of capture based on the existing color scheme and then assign a totally different color to it. For example, if I were to take a photo of a red apple against a white background with nothing else whatsoever in the photo, and lets say i wanted to pick the red of the apple and assign a totally different color to it, say make the apple green or yellow instead. Is there such a tool that allow such an operation?
There are various tools that will assist you in making the sort of edit that you describe.  In many cases, like a red apple against a white background, the tools can make the process almost automatic.  In other cases, the process can be very labor intensive to get a good result.  

As I mentioned above, if you use the blending options for layers in Photoshop, you can apply an edit only to regions of a specified color range, such as white or red.  There are also tools in Photoshop that allow you to select areas based on color or tonality and then apply edits only to the selected areas.  There are whole books written about how to do that.  There are also software add-ons sold that assist in the process.  Basically, Photoshop is the tool of choice, and depending on the particular image there are often multiple ways to approach the task.

In Lightroom (or Adobe Camera Raw) there are several tools that may work for some images.  The Adjustment Brush has an Auto Mask feature that will assist you in applying adjustments just to a particular object--it would probably do a decent job of selecting your red apple.  Also the HSL tools allow you to make adjustments that apply just to particular color ranges.  But overall, Lightroom and ACR are not the tools of choice for the sort of edits you're talking about.
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John DeMott
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