Sharpening by Blurring

[John Rostron]

Sharpening by Blurring

This procedure originated from Dan Margulis and I found it described in The Creative Digital Darkroom by Katrin Eismann and Sean Duggan (Page 387). It utilizes two copies of the original file which are transformed, one into a Light Edges and the other into a Dark Edges image. These are then stacked onto the original with appropriate blending modes to create a final sharpened image.

The original used Photoshop. I have translated it as far as I can into Affinity Photo procedures.

1.      First, create two new tabbed-copies of the background image.

Photoshop allows you to to do this as a recordable command. In Photo I used the following:

Edit > Copy (Control-A, Control-V)  (or Command-A, Command-V)

Edit> New from Clipboard.

Edit> New from Clipboard.

This creates two new tabs, each with a copy of the original image.

2.      Create the Light Edges

On the first extra image, duplicate (Ctrl/Cmd -J) the Background Layer twice

Select the Middle Layer

Apply a Gaussian Blur Filter (Filter > Blur > Gaussian Blur) with radius 1.5.

Change the Blend Mode to Darken.

Select the Topmost Layer and set the Blend Mode to Difference.

Flatten the Image (Document > Flatten).

Duplicate the single layer and set the Blend Mode to Screen.

Duplicate this top layer again.

Flatten the Image.

Rename this layer to Light Edges.

The result will be a very dark image with fine light lines corresponding to the edges.

3.      Create the Dark Edges

On the other extra image, duplicate the background layer twice.

Select the Middle Layer.

Apply a Gaussian Blur Filter (Filter > Blur > Gaussian Blur) with radius 2.

Change the Blend Mode to Lighten.

Select the Topmost Layer and change the Blend Mode to Difference.

Flatten the image.

Invert the image (Ctrl/Cmnd-I).

Duplicate this background layer.

Change the Blend Mode to Multiply.

Duplicate this layer again.

Flatten the image.

Change the Layer Name to Dark Edges

The result will be a very light image with fine dark lines corresponding to the edges.

4.      Bring it all together

Select the Dark Edges image and Copy (Ctrl/Cmd-C).

Select the original image and Paste (Ctrl/Cmd-V).

Set the Blend Mode to Multiply.

Select the Light Edges image and Copy (Ctrl/Cmd-C).

Select the original image and Paste (Ctrl/Cmd-V).

Set the Blend Mode to Screen.

 

I have created two macros to perform the Light Edge and Dark edge manipulations of stages two and three. Although Photo will quite happily create a macro that copies and pastes layers between documents, it records the actual layers present at the time of the recording, not the command to perform the copy.

To apply these to a document, you need to manually go through the steps in stage one to create the two copies. Then Apply the Light Edges macro to one of these tabs and the Dark Edges macro to the other tab. Finally manually go through the steps in stage four.

Dark Edges.afmacro

Light Edges.afmacro

John

 

[smadell]

Good morning, @John Rostron. I was intrigued by your method, and tried it. I found that it produced a nice, sharp image in a different way. I thought there had to be a way to do all of this inside of a single file (and, therefore, make it amenable to an inclusive macro). I found that I could create the Light Edges and the Dark Edges inside of Groups, which were then rasterized. I then went about incorporating your instructions to a single macro. This brings together all of the steps you outlined above (except the creation of separate documents, of course) and then combines the Light and Dark Edges layers into a Group. In that way, the whole effect can be turned on/off with a single click. It can also be made less conspicuous by tweaking the Opacity of the group.

I have attached the macro I created to this post. It is an .afmacros file, meaning it will import into the Library as a Macro Category. Users can drag the macro into one of their existing categories, if they like, and then discard the empty category they imported. I posted this as a category instead of as a single macro so that it could also be imported into the iPad version (although I confess I have not yet tested it out on my iPad – I am assuming it will work, and I hope I am correct).

Sharpening by Blurring.afmacros.zip

[John Rostron]

Thanks, @smadell. I did make several attempts to combine all this into one macro, without success. Well done for your effort.

BTW, it is not my method, but Don Margulis's.

John

[NotMyFault]

Hi John,

The image attached is a hyper-simplified version of a similar more complex workflow (using apply image and multiple copies). one group of three layer. It doesn't need any layer copies, macros, or destructive operations.

• Currently it uses a bilateral blur, but you can replace it by any blur.
• Currently it affects both darker and lighter edges. This can be extended to handle them separately using two copies of the group, adjust blend ranges and blend mode. But maybe the "combined" version provides as good results as using separation.
• You might use this as inspiration to replace copies / destructive edit steps by fully non-destructive steps.

sharpen by bilateral blur 2.afphoto