Making a photo with a gray sky brighter

Making a gray day brighter preview

In this photo manipulation tutorial we’ll have a look at how to make a gray day brighter. We will remove the clouds and create a new sky, we’ll also do brightness adjustment on the entire image, and also some color adjustment on different parts of the image with the help of some advanced selection tools.


Here’s a half-and-half split of the image so you can see before and after.

Making a gray day brighter half-and-half

The photo we’ll be using is from, you can download it here.
(when window opens Right-click on it and choose “Save as”)

Step 1

The JPG format doesn’t support transparency, but we kind of need that while we work on the image, so the first thing we’re going to do is to add support for transparency.

Simply click on Layer->Transparency->Add Alpha Channel.
That’s it, now we have support for transparency.

Step 2

Now let’s make the image brighter.
Go to Colors->Brightness and Contrast.

For this image it looks nice with Brightness set to 40, and Contrast set to 35.

This of course varies with different photos and also the brightness of your monitor, some monitors (especially CRT monitors) are really dark and then you would want a higher value. You should always play around with the settings to see what looks best.

Brightness and Contrast settings in Gimp

Step 3

Let’s remove those clouds. Choose the Fuzzy Select tool and set the Threshold to 20.
Also enable Feather edges and set them to 2, this will help make the edges smooth.

Enable Feather edges in gimp

Hold in Shift, and click on the clouds a couple of times in different places until the entire sky is selected.

Selection of sky

Now hit the delete button on your keyboard.

Delete the sky

Step 4

We’re going to create a new sky without clouds.

First of all, get rid of the selection. Select->None.
Second, create a new layer underneath the other layer and name it sky.
Set your FG color to afe3f6, and your BG color to d6edf6.
Select the Blend tool, you shouldn’t need to adjust any settings.

FG color and BG color

On the layer named “sky”, create a gradient from the top of the image to where the sky starts.
(hold Ctrl to get a straight line)
Drawing gradient

That should give us this result

New sky

Step 5

We’re also going to make the beach a little brighter and the grass a little greener.
These are minor details and doesn’t add that much to the photo, but if you want to learn some advanced selecting then read on.

Let’s do the beach first.
The beach is a very tricky selection because on the very left side of the photo parts of the beach only show through openings in the grass.

First make sure you’re working on the layer with the beach and not the layer with the sky.

Now select the Select by Color Tool and set the Threshold to around 25.
Hold in Shift, then click on the beach a couple times in different areas, try to click in areas with different colors, such as one click on a dark color, then one click on a medium bright color, and one click on a bright color.

That should give us a selection somewhat like this:

Selection by color

Next, enable the Quick Mask. (Shift+Q). This mask controls our selection, the red parts are the parts of the image that are not selected.

Quick Mask enabled in Gimp

As you can see, a lot of areas that shouldn’t be selected are selected, such as very small parts of the ocean and grass.

To fix this, set your color to black and select the Pencil Tool.
Now simply paint the parts of our image that we don’t want to be selected.

Also, if there are any parts on the beach that should be in the selection but aren’t, then set your color to white and paint over those areas.

If you have trouble seeing what is sand and what is water or grass you can toggle back and forth from normal view to Quick Mask view with Shift+Q.

After a some work it should look like this:
(Click on the image to enlarge it)

Click to enlarge

Disable the Quick Mask (Shift+Q).
Now we have a nice selection of the beach, including the parts of the beach that only
shows through openings in the grass.

Selection of beach

Step 6

Now let’s put that selection to good use, go to Colors->Brightness and Contrast.

Set Brightness to 20 and Contrast to 10.

Adjust Brightness and Contrast of beach

Don’t loose that selection just yet, we’re going to use it in the next step.

Step 7

Now let’s make the grass greener.
First we need to invert the selection. Select->Invert

Next, enable the Quick Mask (Shift+Q).
Things should look like this:

Quick Mask of everything but beach

Use the Pencil Tool to paint all the areas that shouldn’t be selected with black.
I thought the grass closest to the bottom of the image is fine as it is so I also painted over that,
leaving only the grass in the middle.

Quick Mask with grass selected

Disable the Quick Mask (Shift+Q)
Now we have a selection of only the grass.
Now click on Colors->Hue and Saturation.

When trying to find the right color, I find it easiest to first play around with Hue until you have a color you like, then adjust the color with Lightness and Saturation until it looks good.

In this case I like these settings:
Hue to 10
Lightness to 5
Saturation to 5

Gimp Hue and Saturation options

Step 8

Go to Select->None so that we can see our final image clearly:

Click to enlarge

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    September 15th, 2010

    Thanks. This is one the best text (and images) based gimp tutorials that I’ve seen, if not the best.

  2. linusik

    May 20th, 2011

    awesome. fast and easy 🙂 thank you!

  3. TC

    January 7th, 2015


  4. Mongan Tithesis

    July 19th, 2015

    Insufficient instructions for step 4, so couldn’t continue. How do you “create a new layer underneath the other layer”; and how do you get the Foreground/Background dialogue?

  5. yay

    July 20th, 2015

    Mongan Tithesis:
    Create a new layer by clicking on the new layer button. (You can see it in the image in step 4, it’s the leftmost button at the bottom of the window to the right) Then use the arrows right next to it to move the layer below the background layer.

    To change Foreground color, doubleclick on it. (see image in step 4 to see where it is located), a small window will pop up enabling you to select colors, and you can input a numerical value for the color you want in that window. Likewise for background color.

  6. Mongan Tithesis

    July 20th, 2015

    Many thanks indeed yay; with your help I think I’ve got the hang of it now. It’s my first foray into the world of layers, masks and transparencies, and I must say I find it fascinating. I’ve read forums on which Gimp is unfavourably compared with Photoshop, but for a free program it seems very sophisticated and effective to me. I’m using version 2.8 by the way.

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