If I knew how to insert images in the text as I went along this would be easier! However:

Create a duplicate layer,
Use Select > color range. Use the LH dropper for initial selection then the middle + dropper (or -)to add (remove) other area clicking in the sky area until you think you've got the sky area of interest (not precise but this selection took less than a minute and 3 or 4 dropper clicks) I tend to use 'quick mask' display to see where things are ahppening. See first screen grab below


Once you think you have a reasonable selection, Click OK to get 'marching ants'

You may then need to experiment with Select > modify. I typically increases the selection by 2 or 3 pixels, then feather by 1 or 2 pixels. This will usually ensure no ghost edge is visible on the selection and blend anything you do afterwards (like color fill!) - and not a big deal on foliage but could be on a persons hair.

Make sure layers window is selected then click on the mask icon at the bottom (3rd along in this screen grab) See screen grab 2 below


Hold Alt and click over the layer mask icon to show the mask full screen

Select the paintbrush tool. Use X key to toggle between black and white brush (white reveals and black conceals.) Paint over the bits of the mask you don't want to include in the mask selection

See screen grab 3

Obviously the bigger the brush the quicker but more coarse the result. With this image I used a 40 pixel brush and took a minute but it would take a bit longer if I was working with a high res image I wanted to enlarge :) see screen grab 4

Once you have painted out all non-sky, Press esc to exit full screen edit of mask

Once you finish the mask decide if you want to replace the sky or just give it a bit of colour. As this was not a 'Big sky' I just used a single color to fill for this demo. If you want to replace with an actual sky the principle is the same, except use a layer mask with the new sky as already suggested instead of a sold color fill layer.
To use a solid color, Layer > create new fill layer > solid color see screen grab 5

Once you have a colour you like click OK.

Then click and hold the layer mask icon from the previous layer, drag and drop it over the new solid color layer and click Yes see screen grab 6

Tidy up layers and done. This demo took less than 5 minutes but obviously a lot more care would be required with masking for a presentation enlargement but still less than 1/2 hr I think, maybe an hour tops?

There are several other ways to do this but this works for me and is quick. Hope this helps - PS is so comprehensive it took me ages to piece all these bits together!!

Sometimes this works, sometimes not but give it a try... Replace sky thru trees tutorial. Based on Photoshop.

Open Picture you are working on. Open separate photo with replacement sky. Select all. Edit-Copy. Or Do a selection; then copy & paste over original.

Paste over original... Select Darken... adjust opacity.

choose colors Black and White on left menu. (Ctrl D)

Open Gradient tool: Linear Foreground to transparent

Draw straight line over sky are going upward

adjust capacity again

You may need to make some adjustments but this should get you close.

Good Luck

Hey pp experts, I have a photo that has a white (cloudy) sky behind a complex structure of tree limbs with colorful leaves. I've looked at a dozen tutorials on changing sky color (to blue) but every one uses a mask from another photo employing erasing or painting to get around foreground objects. This, if not impossible, would take a year (for me) with this photo because of the complex tree structure with lots of sky showing through between leaves and limbs.

I would think there should be a way to isolate part of the photo to be changed and then just adjust/change one of the colors in that part; in this case the white sky to blue but I have not been able to find a tutorial that shows how to do that. I'm using Luminar, but even a photoshop tutorial may help as I may be able to translate the method to Luminar.

Thanks in advance for any helpful answers.