How to Brighten Up Dark Photos Without Blowing Highlights, Using FREE Software

Where We're Going

Take a look at the bright photo in this first section.

That's where we're going.

We started with the dark photo in the next section.

Notice that we were able to brighten the shadows in the dark photo, without losing detail in the sky.

It's not tricky to brighten a photo and blow out the highlights. You just move a slider. But blown highlights degrade the quality of photos (although they can be used for artistic effect).

It takes work to brighten a photo and retain detail in the highlights.

If you have never worked with layers in a photo, this article will teach you how.

Read on!

Dark photos

Maybe you have a few photos that look like this in your collection:

Would you believe that I took the photo this way on purpose?

I really like skies, and when I was composing the picture, I wanted the clouds to come out. If I had brightened up the exposure, then the buildings and the people would have looked great, but the sky would have been blown out to white.

The good news is that you can fix photos like this, and get a result where the buildings and people are bright and the sky still holds some detail.

Get Gimp

I'm going to use gimp for this article. Gimp is a powerful image editing tool. It's free.

Download gimp here. You need to click on Show other downloads at the bottom of the GIMP for LInux section (first section) to see all available downloads.

Gimp works on Windows, Linux, Mac, and most other platforms.

Getting Started

Open gimp.

If you haven't used gimp before, don't freak out when you see the interface!

It's a little intimidating, because there are so many options, and a little annoying, because it is divided into more than one window. That's the tradeoff for getting virtually all the power of PhotoShop free. By the end of this article, gimp will seem less intimidating to you.

Open up a file that you want to work on. You can use the dark picture above if you want to follow along with the changes I make, or you can use a file of your own. Use the File -> Open... menu to open the file, just as in any other program.

You should now have something that looks roughly like this in front of you:

There are three windows open, the image window, the toolbox, and the channels, paths, undo, and layers dialog.

The only window of these three that you might not have open by default is the channels, paths, undo, and layers dialog. If you don't see it, right click on the image and select Windows -> Recently Closed Docks, and you will be able to choose it there.

You need these three windows open to follow along with this article. You can close any other windows that might be open.

If you want to resize your image, right click on the image and choose View -> Zoom, then choose the zoom amount that you want. You can fine tune the zoom percentage to anything you want.

Overlay Mask

The first thing we're going to do is brighten up the shadows a little bit, with an overlay mask.

1. Create a duplicate layer by pressing on the duplicate layer button in the layer's dialog. Make sure the layers tab is selected inside the dialog first.

2. Right click on the new layer, choose Edit Layer Attributes..., and rename the layer "Overlay". This is not absolutely necessary, but it helps keep track of things.

The blue color on the Overlay layer means that the Overlay layer is selected. Make sure that your dialog box looks like the one in the picture, and that the Overlay layer is selected, before continuing.

3. Right click on the image, choose Colors -> Invert. Right click again, choose Colors -> Desaturate... Click OK to accept the default.

4. Right click on the image, choose Layer -> Mask -> Add Layer Mask... Choose Grayscale copy of layer, and click Add.

5. Left click where it says Normal next to Mode: at the top of the Layers dialog box, and choose Overlay from the drop-down menu.

Congratulation! You have created an overlay layer which lightens the shadows in the photo a little bit, without lifting the highlights. Your dialog should look like this now:

How layers work

Layers are stacked on top of each other. You see only the top layer, unless it is invisible, transparent, or opaque. If it is invisible or transparent, you see the next layer. If it is opaque, you see part of the top layer, and part of the layer underneath.

Overlay mode is opaque. You see part of the top layer, and part of the layer underneath. If you click on the eye button to the left of the Overlay layer, then the Overlay layer becomes invisible and you can only see the darker bottom layer that we started with.

Click the eye button to the left of the Overlay button on and off a few times, to see how the Overlay layer has lightened the shadows in the original image.

You can further control the opacity of the Overlay layer, or any layer, with the opacity slider underneath the drop-down mode menu. Move the slider back and forth a few times (make sure that the Overlay layer is visible) to see how you can finely adjust the effect that we just created. Then move it back to 100%. We are going to leave the opacity at 100% for this article, because the photo is really dark and we want to lighten it up all that we can.

Screen Mask

This layer will really lighten up the image.

1. Highlight the Background layer, so that it is blue.

2. Create a duplicate layer by pressing the duplicate layer button. Highlight the new layer, and use the arrows to the left of the duplicate layer button to move the new layer to the top of the stack. Rename the new layer "Screen".

3. Add layer mask to the Screen layer, a grayscale copy of the layer as in the previous example.

4. The layer mask should be highlighted in the Layers dialog. Check to see that it is highlighted with a white box around it. If it isn't, click on the layer mask in the dialog box to highlight it. Now click inside the image, and invert the colors as you did when making the Overlay mask. It will look like nothing happened. That's because you inverted the colors in the layer mask, not the layer itself, and the layer mask is invisible. But you will be able to see the inverted colors in the layer mask in the layers dialog box, if you look.

5. With the Screen layer selected, choose "Screen" mode from the drop-down mode menu.

Wow! That really made a difference, didn't it?

Your dialog box should now look like this:

And your image should look like this:

Better, but we're still not there yet.

But we have a few more tricks up our sleeve.

Duplicate the Screen Layer

Here is a cheap trick that will take advantage of our previous work.

Highlight the Screen layer, and duplicate the layer. Now duplicate it again.

Voila! Triple the screening.

And we're more or less done.

Your Layers dialog should now look like this:

And your image should look like this:

Saving Your Image

Make sure that you do not have a layer mask selected in the Layer's dialog.

Right click in the image, then click File->Save. Give the image any name you want, and an extension. Gimp will save the file according to the extension. For example, my-pic.jpg will be saved as a jpg file, my-pic.tif will be saved as a tiff file, and so on. Gimp understands most popular file extensions.

Important Hint: If you want to keep working on your layers at a later time, use gimp's native format, which is .xcf. The reason is that some other formats, like jpg, do not support layers, so gimp will flatten your image out when saving jpgs, whether you like it or not. That's OK if you are done working on your image, but it will bum you out if you're not.

Final Thoughts

I increased the contrast in the final image, and desaturated the colors. I did this after posting the final image, so you don't see those changes here. Articles on those subjects will have to come at a later date.

Once you are good at this stuff, you can work fast. All of the changes that we did in this article took me less than a minute!

Why go to all this trouble? The reason is that you have fine control over how your image is brightened, and most importantly you preserve the highlights in the image.

There are other techniques for brightening images. I use them all the time. I mix techniques and match them. Here we could have used two instead of three screen layers, or dropped the opacity on one of them to 48%, etc. etc. The important thing is to try to get a feel for how this stuff works, so that you can develop your own style.

Please let me know if this article was useful to you.

Happy gimping!


Don't forget to look at my other photography articles.

Five Easy Tips that will Improve Your Photos!

How many pixels are enough?

Comments 1 comment

JP 3 years ago

Wow, excellent tutorial, one of the most useful I've seen about gimp, thanks so much!

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