recently i shot this image where the sky was overexposed and neat replacing this happened
even though i was using a three-stop reverse nd grad filter to reduce its brightness fortunately
i spotted the problem at the time and took this second shot where i reduced the exposure by three
stops in today's video i'll show you how to easily fix exposure problems like this by replacing the
sky using affinity photo i'm starting with both of the images open in affinity photo my first step is
to copy the dark image onto the light image as a new layer i can do this by right-clicking on the
background layer with my mouse then selecting copy from the pop-up menu i'll then switch to editing
the overexposed image where i can right click using my mouse in the popup menu i'll select the
option to paste the image i copied as a new layer i now have both images open in the same affinity
photo document as separate layers when i'm making a repair like this i prefer to have the image with
the darker sky as the top layer of the two next i'll rename the two layers to be sky and ground
so that i can quickly see what each is used for now i'll add a layer mask to the sky layer
which i'll use to reveal just the sky from the darker image to do this select the sky layer
by clicking with the mouse then click the mask layer icon at the bottom of the layer studio panel
when the new mask appears i'll click it using my mouse to make sure it's selected now i can invert
the mask by pressing command i on my keyboard which is ctrl i if you're using a windows pc
you can see here that this has turned the mask black which completely hides the dark sky layer
now all we can see is the lighter ground layer with the well exposed heather and rocks
the next step is to paint in the sky from the darker layer to replace the overexposed
sky we do this by painting with white on the layer mask using the paint brush tool
the trick to replacing the sky is to blend the two images together so they appear natural this
means we need to avoid hard edges between the sky and ground and any halos it could produce we can
achieve this by painting through a selection created using the lightest pixels in the image
now we have a few methods we could use to select the light areas of the image the one that i find
easiest and which works with most images is to load one of the colour channels from the ground
layer when i click the channel studio panel you can see the composite red green and blue colour
channels in the image if i click one of these channels you can see that it's displayed as a
black and white image what i want to find is a channel that separates the sky from the hillside
but which has a soft blend between the two if you look at the red channel here you can
see that the sky is white and the hills in the background are slightly darker this is what we
want to see but there's another problem with this channel because some of the fields are too light
if we paint through a selection created from the red channel we'll end up replacing the fields as
well as the sky compare this now to the blue channel where you see the same fields are grey
this will probably make a better channel to use to make a selection to replace the sky to use the
channel i'll right click on it with the mouse then in the pop-up menu i can click the option
load to pixel selection when the channel loads you can see the marching ants appear on the image
this shows that there's an active selection we can now use but before continuing i'm just going
to reset the channel window so that we see the color image again rather than the blue channel
to do this click the arrow icon to the top right of the panel
now let's select the paintbrush tool from the tools palette on the left to paint in
the replacement sky we want to use a soft brush to help with blending the new sky making it look
natural i'll therefore set the hardness slider to zero percent which creates a soft edge to the
brush i'm then going to leave the flow set to 100 but i'll reduce the opacity to about 60 percent
this means i'll need to make several brush strokes to paint in the sky which also helps with the
blending now i can paint on the layer mask using white where i want to reveal the darker sky layer
if you find the matching ants are blocking your view you can easily hide them in the view menu
this only hides the selection but the selection itself remains active sometimes when you paint in
a new replacement sky you may want to retain some lighter areas to make the image appear
more believable to do this is simple just don't paint over these areas of the mask as much it can
also help to reduce the opacity of the brush once you've made a couple of brush strokes if you find
that some areas are becoming too dark switch to painting with black on the mask rather than white
you can do this by pressing x on your keyboard when you paint over areas of a layer mask with
black it hides the darker layer making the image lighter we now have a reasonable blend between
the ground and the new replacement sky but we can do more to balance the exposure between the two
now before continuing i'm just going to clear my selection with the deselect option in the
select menu i can then add a levels adjustment to both the ground and sky layers to refine the
exposure of each to do this i'll select the ground layer in the layer studio panel by clicking it
then i'll click the adjustments icon at the bottom of the layers panel and choose levels
from the menu you can then move the black white and gamma levels to adjust the layer's exposure
because the levels adjustment appears above the ground layer but below the sky layer
it only affects the ground next i'll select the sky layer and add a levels adjustment above that
this time when i adjust the levels it affects all the layers below it in the layers panel
because i only want to adjust the sky i can click and drag the levels layer and
drop it onto the sky in the studio's panel it then reappears attached to the sky layer
and only affects that layer now i can safely make my adjustments to the sky to improve the exposure
with the exposure balance between the sky and ground the image is now looking much
better let's compare that to the original ground layer and you can see the improvement this makes
i can then finish off the image with any further adjustments i need to make i also want to mention
that there's a second method you can use to create a more accurate selection of the sky this involves
creating a luminosity mask as i explained in this video the technique uses a simple curves
adjustment and allows you to target different areas of an image based on their brightness i hope
you found this video helpful thanks for watching and i hope you'll visit again in the future