Diffuse Glow Filter in Affinity Photo Tutorial

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By Andrew Buckle, Updated : 2022


Diffuse glow filter in Affinity Photo for amazing blurry effects with images and text etc, brightening / glowing and blurring at the same time



1. Where is the diffuse glow filter in Affinity Photo

The diffuse glow filter in Affinity Photo can be found in the blur category under the filter menu command. The filter is a powerful diffuse tool but it is a destructive filter effect that modifies any image etc. There is an equivalent non destructive one in the layer menu and live filter layers.


2. Basic use of the Diffuse Glow filter

The diffuse glow requires a layer to work, if there is no layer, the command will not be enabled. The layer can be an image as well as shape or text etc. It comes with three basic settings and that is radius and intensity and threshold and opacity. As with all filters you can set the values to the minimum and maximum and in between and the result will be very different. The diffuse glow filter has a threshold setting and as with many threshold settings, the lower the value the more of the filter effect is seen, so if you set it to 100% you will see little effect.


Set the value of the radius to a high value to create a more dreamy effect


Set the intensity and opacity high and you get virtual snow as all the lighter parts of the image are blasted away to leave the image white.


3. Use the diffuse glow on a duplicated layer

Go to the layer menu and duplicate the current layer and then apply the diffuse glow filter to that and now you can bring in layers and blending modes and opacity to blend the effect layer as well as the original source layer (or perhaps add an effect to that but a different one such as a standard Affinity Photo blur). You can create all kinds of weird and wonderful diffuse glows with blending modes such as divide or difference or darken etc


You can also re-size the layers and combine them that way with the effect. You can also combine the result with other layers as well such as using a shape layer to re-color the artwork and that also can have an associated blending mode set via the layers panel


4. Pattern layer and the diffuse glow filter

One of my favorite recent features of Affinity Photo has to be the pattern layers and selection from a pattern layer found in the layer menu and it works well with the diffuse glow filter, either applied to an image beforehand and then turned into a pattern layer or adding the effect to the layer. Works even better if you combine it with the powerful filter layer option as the values can then be modified


5. Live filter layer and diffuse glow

I love the powerful live filter layers as you can add them once or multiple times via the layer menu and new live filter layer, you can also double click on the diffuse glow entry in the layers panel and change the settings and make a radical change to the image in a non destructive way. You can also add into the mix the wonderful blending modes such as difference and divide and darken etc which can be used to create all kinds of unique combinations.


6. Selections and Diffuse Glow filter

You can add a selection via many ways in Affinity Photo such as via the select menu as well as simply adding a selection using the freehand selection tool or using the basic rectangular marquee tool. Once you have your selection, you can add the diffuse glow filter to the current selection. You can also invert the selection via the select menu and apply the diffuse glow filter to that.


7. Diffuse glow and repeat applies

The diffuse filter works well with a single apply but as with all filters, sometimes the effect gets even more unusual with repeat applies as you are adding the brightening to more and more brightening. You may prefer to have subtle settings adding little to the image and then repeat apply, though ultimately the image just ends up looking like there has been quite a fall of snow and in the middle of June