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On 7/16/2017 at 1:34 AM, MartinsRibeiro said:

In Photoshop, you have to:

1 - create two layers

2 - blur the bottom layer

3 - subtract the bottom layer from the upper layer

4 - change the top layer blending mode to Linear Light.

 

On 7/16/2017 at 3:46 AM, toltec said:

That is an interesting approach but not what I would call "Frequency Separation".

I realize this is an old post, but for anyone who might be interested, the steps outlined by MartinsRibeiro are exactly what Frequency Separation is, and presumably the same steps that the AP Frequency Separation filter is actually doing for you behind the scenes (there is more than one way to achieve the same result, but essentially the same).

When you blur the first copy of the image, you're effectively applying a "low pass filter" which removes the high frequency components (the "details") and leaves the low frequency components (the "colors").

When you subtract that blurred version of the image from the second copy, the low frequency components are removed from the second copy, leaving only the high frequency components.  This is equivalent to applying a high pass filter that is the exact inverse of the low pass filter used in the previous step.

So now you have two layers which contain the low frequencies in one layer and the high frequencies in the other layer.  These two frequency ranges have been "separated" out from one layer into two layers.  Setting the blend mode of the top (high frequency) layer to linear light then adds the two ranges of frequencies back together, re-creating the original image.

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On 6/11/2018 at 12:57 PM, Fotoloco said:

1. Convert your image to LAB mode.

2. Duplicate the layer, and name the lower one "L" (luminosity) and the upper one "C" (color).

3. Go to the channels studio for "L" and click on the "..." for AOpponent, and click "Clear". Do the same for BOpponent.

4. Go to the channels studio for "C" and click on the "..." for Lightness, and click "Clear" and then "Invert".

5. Change the blend mode for "C" to "Color".

6. Duplicate "L" and name the lower one "L blur", then apply a blur filter of your choice (Gaussian or median, etc.) to this layer.

7. Create a new group named "High pass" and place "L" inside it. Then, duplicate "L blur" and place it above "L" (inside the "High pass" group).

8. Go to the channels studio for the copy of "L blur" inside the "High pass" group, click the "..." for Lightness, and click "Invert". Set the blend opacity to 50% (blend mode normal).

9. Set the blend mode for the "High pass" group to linear light, and then rasterize the group if you wish.

 

So how is this done in Affinity Photo for desktop (Mac)? I'm struggling to follow the directions in the Channel Studio for the desktop version.

 

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Apologies to Lance_G, this does not answer your question directly, but there is a recently posted series of videos on YouTube by D. Straker that covers frequency separation in Affinity Photo. The most technical one ("How It Works, In Detail!") shows, with excellent visuals, how the step-by-step process works for RGB images. The  following link gets you to the series, or search for "InAffinity" and "Frequency Separation." (I have not viewed the more basic videos.)

 


AP 1.7.3, MacOS 10.14.6 (usually latest of each, but not going to Catalina until more issues are resolved)

Mac Mini, Late 2012, 2.5 GHz Intel Core i5, 8 GB; HD replaced with SSD

 

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11 hours ago, Lance_G said:

So how is this done in Affinity Photo for desktop (Mac)? I'm struggling to follow the directions in the Channel Studio for the desktop version.

 

Here you go
I see an issue with changing to LAB. It also changes the color profile of the image. I haven't tested the LAB solution so I don't know if it gives you better results that the traditional one.

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4 hours ago, MartinsRibeiro said:

Was there anything I was supposed to see here? All I get (on my tablet) is a totally black screen.

John


Windows 10, Affinity Photo 1.8,5 Designer 1.8.5 and Publisher 1.8.5 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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3 minutes ago, John Rostron said:

Was there anything I was supposed to see here? All I get (on my tablet) is a totally black screen.

I get ten seconds of video when I view the post on my iPad.


Alfred online2long.gif
Affinity Designer/Photo/Publisher for Windows 1.9.0 • Windows 10 Home (4th gen Core i3 CPU)
Affinity Photo for iPad 1.9.0 • Designer for iPad 1.9.0 • iPadOS 14.4 (iPad Air 2)

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On 7/19/2017 at 11:05 PM, MartinsRibeiro said:

Issue solved! This is useful to subtract one layer from the other, for example for Frequency separation.

 

So this is how I did it for a 8 bits image (16 bits should need a change in the 2 and .5 values bellow)

 

1 - Create two layers with the same image 

2 - Change the layer bellow as you like (gaussian blur, median blur or anything else)

3 - Make the top layer Linear Light (could be done afterwords but if you do it before Applying image, it's easy to see the result as it happens)

4 - Apply image with the following parameters:

Source: layer bellow modified

Blend mode: Normal

Equations: on

DR=(DR-SR)/2+0.5

DG=(DG-SG)/2+0.5

DB=(DB-SB)/2+0.5

DA=DA (no change to the Alpha )

 

A couple of explanations. In the equations:

DR stands for Destination Red an is the value of the Red in the layer you chose to Apply image (in this case the top Layer)

SR stands for Source Red and is the value of the Red in the source layer (in this case the layer bellow)

The 2 and 0.5 are based on this info: https://helpx.adobe.com/photoshop/using/channel-calculations.html (look for "Add and Subtract blending modes")

 

Hope this helps for future reference.

Captura de ecrã 2017-07-19, às 21.51.12.png

OMG I was trying just this, with the same math and the same process, but I was picking the wrong blend mode. It has all the sense to let it in Normal and do all the maths. Thank you. THANK YOU.

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1 hour ago, fde101 said:

I'd like to suggest putting in a feature request to add a popup menu to the built-in Frequency Separation tool to let the user select the type of blur to be used.

Already done here: 

 

Just go there and help pushing it up by commenting it.

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On 7/19/2017 at 11:05 PM, MartinsRibeiro said:

Issue solved! This is useful to subtract one layer from the other, for example for Frequency separation.

So this is how I did it for a 8 bits image (16 bits should need a change in the 2 and .5 values bellow)

 

 

Does anybody know how to do it with an 16bits image?

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On 8/17/2019 at 5:57 AM, MartinsRibeiro said:

 Should be exactly the same thing 

Just revisiting this, you say it should be the same thing, but earlier you say the values probably need to change for 16 bit. Which is it? BTW, thanks for your work on this.


iPad Pro 12.9 3rd Gen/Hackintosh, in that order

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9 hours ago, wgphoto said:

Just revisiting this, you say it should be the same thing, but earlier you say the values probably need to change for 16 bit. Which is it? BTW, thanks for your work on this.

As far as I can tell, the values are the same for 8bit, 16bit and 32bit
In Photoshop apparently there is the need for different values for each bit depth version (I haven't tested it)

In the tests I've carried in Affinity, the values work exactly the same way independent of the bit depth of the image.

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On 7/16/2017 at 3:34 PM, MartinsRibeiro said:

Yes, that's the video.

 

Let me explain a little better. In Affinity, you just got to Filters/Frequency Separation and that's it.

 

In Photoshop, you have to:

1 - create two layers

2 - blur the bottom layer

3 - subtract the bottom layer from the upper layer

4 - change the top layer blending mode to Linear Light.

 

Now, what I'm looking for is to recreate the steps on the photoshop, specially the step 3. Why? Because I don't like the gaussian blur and prefer to use median blur, and the Affinity filter uses gaussian blur.

 

So the problem I have is with Apply Image. It doesn't have the same parameters as Photoshop, and I cannot recreate the effect.

 

Hope this help clarifying what I'm looking for, and thank you for taking the time 

Hi , 

please let me know how to do the the 3rd step the same as photoshop , I wanna subtract the First later from the second layer , 

the first layer is the original image , 

the second layer is the one that I dodged and burnt , 

Now I wanna subtract the two so I get only dodged one so I could change the colors and other stuffs only on the subtracted layer not on the entire image . 

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Use the Subtract Blending Mode. Note that you may first need to reverse the order of the layers to get the effect you want. Then Layer > Merge visible. This would give you a new merged layer that you can work on.

John


Windows 10, Affinity Photo 1.8,5 Designer 1.8.5 and Publisher 1.8.5 (mainly Photo), now ex-Adobe CC

CPU: AMD A6-3670. RAM: 16 GB DDR3 @ 666MHz, Graphics: 2047MB NVIDIA GeForce GT 630

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3 hours ago, Adammmmmm said:

Hi , 

please let me know how to do the the 3rd step the same as photoshop , I wanna subtract the First later from the second layer , 

the first layer is the original image , 

the second layer is the one that I dodged and burnt , 

Now I wanna subtract the two so I get only dodged one so I could change the colors and other stuffs only on the subtracted layer not on the entire image . 

See here 

It's the part of Apply image (step 4 of my explanation)

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On 6/11/2018 at 7:57 PM, Fotoloco said:

1. Convert your image to LAB mode.

2. Duplicate the layer, and name the lower one "L" (luminosity) and the upper one "C" (color).

3. Go to the channels studio for "L" and click on the "..." for AOpponent, and click "Clear". Do the same for BOpponent.

4. Go to the channels studio for "C" and click on the "..." for Lightness, and click "Clear" and then "Invert".

5. Change the blend mode for "C" to "Color".

6. Duplicate "L" and name the lower one "L blur", then apply a blur filter of your choice (Gaussian or median, etc.) to this layer.

7. Create a new group named "High pass" and place "L" inside it. Then, duplicate "L blur" and place it above "L" (inside the "High pass" group).

8. Go to the channels studio for the copy of "L blur" inside the "High pass" group, click the "..." for Lightness, and click "Invert". Set the blend opacity to 50% (blend mode normal).

9. Set the blend mode for the "High pass" group to linear light, and then rasterize the group if you wish.

 

I will put my penny into the discussion.

To isolate color on a separate layer:

1. Add Curves adjustment and put it into luminosity mode

2. Make 'master curve' horizontal. (see the pic below) Now you see only hue + saturation info, because you've wiped out luminosity

image.png.835d59a29e687143fa36b0f2539c0bb5.png

3. Merge visible and change the mode of the merged layer to color

4. Hide merged layer and go curves layer; change blend mode to color. Now you see black and white image

5. Again, merge visible

6. Now activate the layer from step 3.

Now you have it - color on one layer and luminosity on another

 

What I do not know is: how to make practical use of it:)

 

 

 

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23 minutes ago, melizarev said:

To isolate color on a separate layer

Very clever. I think this should work as a macro, too.

I did not do much checking or add refinements but this quick & dirty color isolate.afmacro file based on your steps seems to work OK.


Affinity Photo 1.9.1, Affinity Designer 1.9.1, Affinity Publisher 1.9.1;  2020 iMac 27"; 3.8GHz i7, Radeon Pro 5700, 32GB RAM; macOS 10.15.7
Affinity Photo 
1.9.1.225 & Affinity Designer 1.9.1 (showing 1.9.7) for iPad; 6th Generation iPad 32 GB; Apple Pencil; iPadOS 14.4 (18D52)

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