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Photoshop Sky Replacement Using Blend-If by John McBay

October 5th, 2018

The following is the first of a 51 page PDF tutorial written by John McBay that you can download here. For those who don’t know John’s work, he has written the e-book, Image Editing for Real Estate available here and created the video series Image Editing for Real Estate available here. Note: John updated the tutorial on 10/7 to include some reader suggestions.

I have been doing sky replacements for many years and have written about them in my e-book, Image Editing for Real Estate Photography, and have also created videos to show the same techniques in my video series of the same name. The method I have been using (creating a selection of the sky using Select > Color Range) is fairly quick and produces good results in most situations.

But recently, I was made aware of another sky replacement technique that usually produces better results, especially around very small items silhouetted against the sky, such as twigs, small branches, and distant foliage, and is just as quick.

I want to thank Ryan Christian, a member of the Flickr Real Estate Photography forum, for pointing out this technique.

  • This tutorial uses the Windows version of Photoshop CC 2018. Many versions of Photoshop, going back quite a few years will have the tools to successfully use this technique. Lightroom and Elements can’t be used.
  • Once you have mastered this technique, you should expect to insert a sky in about 3 to 4 minutes. If there are issues that make the selection difficult and that need careful correction, it might take a couple of extra minutes. For the example I will be using in the tutorial (which required several adjustments to the initial selection), it took less than 6 minutes.
  • References to Photoshop shortcuts such as CTRL + a would be entered as CMD + a, ALT + a as Option + a, on a Macintosh.
  • We will be using layers in this tutorial. Make sure that the Layers panel is visible on the right side of the Photoshop workspace. If it is not, go to Window > click on Layers. You can use this technique even if you are not proficient using Layers. However, Layers are one of Photoshop’s most powerful tools and when you have the time, well worth studying.
  • Make sure the Adjustments panel is visible on the right side of the Photoshop workspace. If it is not, go to Window > click on Adjustments.
  • If you don’t have your own sky library, you should create one. In the meantime, feel free to download a copy of mine: Sky Library
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9 Responses to “Photoshop Sky Replacement Using Blend-If by John McBay”

  • That is a very nice sky blending technique allowing for lots of fine adjustments. However, if you just need a super quick replacement, do the following.

    Takes a minute or two. In Photoshop:

    Import an image of some sky
    Import your house image
    Copy & Paste the entire house pic on top of the sky pic (House pic becomes a layer above the sky)
    Grab the “Quick Selection Tool” in Photoshop. Quick Selection is very smart about selecting the right thing most of the time.
    Delete (backspace key) the sky from your house pic, leaving the new sky, from the layer below, to shine through
    Magnify the edge between the house and the sky, on the house layer, and tweak any errors you see. If Quick Select was was done neatly, you won’t find any.
    If you’re nervous about messing up the original house layer, just duplicate the house layer before selecting sky. The duplicated layer can be used to easily paint back in any missing parts.
    Export to jpg.

    This is not as precise as the blending technique, but it’s way faster. Sometimes faster is better.

  • Thank you John for going into great detail in your instructions,
    I have struggled with accurate sky replacements, and am eager to try this method out.
    I appreciate all the suggestions that have come my way on this site, and would never have got my little part time business off the ground without them.

  • One thing John forgot to do at the end is put in a gradient so the sky gets lighter at the bottom. If you look at any image where the sky is completely blue you will see that the sky goes from a darker blue at the top of the image to a lighter blue when it gets closer to the horizon. Add a white to black gradient so that it is on the layer mask top to bottom. I usually use the gradient tool at about 10% and do it several times to control it. You don’t want to add to much gradient, just enough to make it look natural. Be sure to hold down your shift key when adding the gradient, it will add the gradient parallel to the horizon. This gives the sky a much more natural appearance and makes it blend better with the trees.

  • Sorry for the typo, it should read: “You don’t want to add too much gradient, just enough to make it look natural.”

  • I’m flattered to get a mention! Whoa! Here I was just minding my own business…

  • I want to point out also, that Flatten Image is really important in this sky replacement technique and will, if you’ve moved your sliders right, remove white fringing from around branches and such. I have no idea why Flatten Image does this, but it’s essential if you want your sky looking authentic.

    I also want to say that if you don’t do the gradient at the end like Larry Fields mentioned, you can just go back into the mask (keep the selection made for the sky replacement) and brush over the horizon a bit, but it’s only doable if your sky behind it was tweaked enough to make it brightish.

  • Excellent work John and very comprehensive. Lee, I have used your quick technique but have major problems with complex transition areas with the details of treelines and branches. One can improve the selection and improving the fine detail by adding another layer of the house, converting to B&W for the greatest contrast and make mask selection from there.

    That said, I am now one week into my “Dump Adobe” experiment as the full $49.99 (raised to $52.99)/mo renewal anniversary was September. At anytime can always come back to the $9.99 PS/LR but things are looking encouraging. Replacing them are Capture One for Sony (Lightroom) and Affinity Photo (Photoshop, and non-Sony files since don’t have full version of Capture One). Sky replacement and multiple layer capability was on thing I researched before starting this endeavor. Affinity makes sky replacement even easier. Two primary layers – house and sky (which can be dragged, positioned and even resized). Selection mask house and treeline, then refine (mask menu option) within that selection and paint along horizon areas with fine details missed in the global selection. Save as a mask layer and move it to a child layer position within the sky layer. Almost done. Now just a matter of adjusting layers saturation, tonality, brightness contrast etc for an overall blend. I find it easier than what I use to do in Photoshop.

  • Thanks to everyone that replied. I received a couple of suggestions and I implemented them and republished the tutorial.

  • Larry Gray
    I read your comment above. I tried what you suggested about converting a layer to B&W. I maxed out the contrast and used Select > Color Range to select the sky. As I suspected, it also selected lots of other parts of the image, leaving the same cleanup issues as in my tutorial. Maybe I am missing something.
    Could you explain further about creating the selection and/or mask.
    If you would like to continue this discussion in private, e-mail me at john@peimaging.com.

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