Affinity Photo Colour Replacement Using the HSL Adjustment

In this tutorial, I’m going to explain how to replace any colour in an image using the Affinity Photo HSL Adjustment layer. In a separate tutorial, I explained how to change the colour of an object using the Affinity Photo Colour Replacement Brush. Whilst this was effective, it can take time and patience to realistically paint all the detail. The benefit of using the Affinity Photo HSL Adjustment to replace colours is that it’s faster, non-destructive, and much easier to use than the Colour Replacement Brush.

Affinity Photo Trial Software

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Adding the Affinity Photo HSL Adjustment Layer

Start by opening your image in Affinity Photo. I’ll be using this image of an old door, where I want to change the colour of the door from blue to purple.

Next, add an HSL Adjustment Layer. You’ll find this in the Adjustment Studio Panel which is usually on the right side of the Affinity Photo interface.

If you can’t see the Adjustment Studio Panel, check that it is visible. You can do this by selecting the View menu in Affinity Photo, and then the Studio option. This displays a list of all Studio Panels in Affinity with a tick mark to the left of the visible ones. Find the Adjustment panel in the list and click it to toggle on and off.

Understanding the Affinity Photo HSL Adjustment Dialog

Having added an HSL Adjustment Layer, you should see the HSL Adjustment dialog as shown here.

I’ve numbered some of the controls in dialog to help identify them:

1. Colour Wheel – this will help you understand the changes you’re making to the image.
2. Colour Samples – use these to pick the colour that you want to adjust.
3. Hue Shift, Saturation Shift, and Luminosity Shift sliders – adjust the image colours. The Hue Shift slider will shift the colours in the Colour Wheel either left or right; we’ll look at this in more detail shortly. The Saturation Shift slider reduces or increases the intensity of colour in the image. And the Luminosity Shift slider allows you to make colours lighter or darker.
4. Picker Button – activates a colour Picker tool you can use to select colours to target with the HSL Adjustment.
5. Reset Button – resets all the adjustments in the dialog back to the default. Be careful when using this as it acts on all the controls in the HSL dialog.

Using the Luminosity and Saturation Shift Sliders

There are seven colour samples in the HSL Adjustment dialog, each representing a different colour. But the one on the left is a little different as it has several colours rather than one solid colour. When you select this by clicking it with your mouse, your adjustments will act on all the image colours at once. I will use this sample to demonstrate the Luminosity Shift slider.

When I move the Luminosity Shift slider to the left it darkens all the colours in the image. And when I move it to the right it lightens them.

You can see the result of moving the Luminosity Shift slider right in the screenshot. This causes the image to become light across all the colours. But also notice the outside of the Colour Wheel which has now turned white.

The outside of the Colour Wheel shows the adjustment changes I’ve made using any of the HSL sliders. At the same time, the inside of the Colour Wheel shows the range of image colours that the adjustment’s acting on.

The Saturation Shift slider works in just the same way. Move the slider to the right and you increase the saturation of the selected colour or colours. Move the slider to the left and you reduce the saturation from those colours. Again, noticed the effect of the adjustment on the Colour Wheel in the screenshot.

Now let’s look at the Hue Shift slider.

The HSL Adjustment Hue Shift Slider

The Hue shift slider is like the other HSL sliders. When you move the slider to the left it rotates the colours in the outer part of the Colour Wheel left. A good example of this is the blue of the door. When I move the slider left it moves the colours to the right of the blue (in the Colour Wheel) left. As the colour to the right is purple the blue of the door turns purple.

The only problem with this adjustment is that it’s also affected all the other colours in the image. If I want to replace only the blue colour of the door, I need to pick the blue colour sample.

Replacing Specific Colours with the HSL Adjustment

This time, I’ll start by selecting the blue colour of the door by clicking on the blue colour sample below the Colour Wheel. Now when I move the Hue Shift slider to the left, it only affects the blue of the door.

But there’s something else that I want you to notice in the HSL Adjustment dialog. There are now four dots on the Colour Wheel. These indicate and control the range of colours affected by the adjustment. Between the two inner dots, the colour replacement is at full strength or 100%.

The two outer dots then mark the full extent of the colour replacement. The colour replacement doesn’t affect any colours falling outside the two outer dots. Therefore, the red in the terracotta doesn’t change colour.

Between the inner and outer dots, there is a gradual reduction in the strength of the adjustment. This helps to blend the colour replacement into the image. But if you look closely at the door, you’ll notice this causes a problem, the cyan colours aren’t replaced by purple. That’s because the blue of the colour sample doesn’t match the blue in the door closely enough.

To fix this problem I can click and drag the position of the dots on the Colour Wheel. If I move the left inner dot further to the left, I can include Cyan colours in the adjustment. I can then move the outer dot further left to blend the colour replacement into the image.

Replacing Red Tiles with Blue Using the HSL Adjustment

Now let’s look at replacing the red tiles around the door with blue.

I could do this by creating a new HSL Adjustment layer in Affinity Photo and using that to replace the red in the tiles. But it’s also possible to make the change using the same HSL Adjustment layer. Each colour range in the HSL Adjustment dialog works independently. This means you can replace one colour and then adjust another colour in a completely different way.

When I look at the colour of the red terracotta tiles around the door, I can see they don’t match the red of the colour sample. They are more orange and lie between the red and yellow colour samples. An easy way I can target these is by using the colour Picker tool in the HSL Adjustment dialog.

I’ll start by clicking the red colour sample below the Colour Wheel to select it. Then rather than making any adjustments I’ll then click the colour Picker tool button. This activates the colour Picker tool and I can click on a tile to sample the colour. When I do this, the red colour samples replaced by my selected colour.

You can see in the screenshot that the red colour sample has turned orange. I’ve then moved the Hue Shift slider to the right to replace the red of the tiles with blue. The other change I made was to increase the saturation of the new colour, making it more obvious.

The only problem is that the blue has replaced the red in other areas of the image which I don’t want. I can therefore use a layer mask on the HSL Adjustment layer to prevent it replacing the colour of these areas.

Adding a Layer Mask in Affinity Photo

By adding a new layer mask to the HSL Adjustment layer in Affinity Photo I can prevent the colour replacement affecting selected areas.

I can add a new layer mask in the Layers Studio Panel by clicking the mask layer icon at the bottom of the panel.

After clicking the mask layer icon, a new mask is added to the HSL Adjustment layer. I can then select a black paint brush from the Affinity Photo Tools Palette on the left of the interface to paint the mask.

Using the black paint brush, I can paint over the areas of the image, on the layer mask, where I want to prevent it replacing colours. If I make a mistake with the painting, I can switch to painting with white by pressing X on my keyboard. Then I can paint over the problem area to correct it.

As you can see the finished colour replacement is very convincing.

Affinity Photo HSL Adjustment Summary

As you’ve seen in this tutorial the Affinity Photo HSL Adjustment layer is extremely powerful and fast to use. Once you understand how the Hue Shift slider works in conjunction with the Colour Wheel it becomes easy to control. The results are also extremely realistic.

Don’t forget, if after using the HSL adjustment you find areas of the image where you’re struggling to replace a colour, you can also use the Affinity Photo Colour Replacement Brush. And if you want to see colour replacement demonstrated using the Affinity Photo HSL Adjustment layer, I’ve included a short video below.

I hope you found this tutorial helpful. If you have please share it with other Affinity Photo users.

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