Split – Frequency Separation – Healing and cloning
Similar to the Angry Illusion, Marilyn Monroe and Albert Einstein embed themselves together in this illusion. You will see Albert Einstein at this reading distance but move back a few feet away and you will only see Marilyn Monroe.
The explanation of this phenomenon is actually very simple.
When you combine the HIGH frequency of Einstein to the LOW frequency of Marilyn you
get a mix of both.
Looking close enough, you lose the shape of Marilyn because the texture is all you can see, when you move back, texture is not as noticeable, so you start to only see the shapes of her, and not his detail.
Like I said when I talked about Texture: Perception and distance are very much related.
For ages retouchers have been splitting the image into visual frequencies, to separate
texture from tones and have more control over the tools. Generally used in the past
for textile retouching, but has now expanded to other uses.
Healing and cloning both have their advantages and disadvantages. But this technique
will help you get the most out of those tools.
The healing brush samples texture from the sample area by option (Mac)/alt (PC).
Then, when you paint, it merges the texture from the sample area into the color and
luminosity of the destination area.
The advantage is that you can use it on an empty layer and get natural looking results.
The disadvantage is that you can’t control the amount of texture or the amount of
The Clone tool doesn’t make this distinction and just samples everything from the
source point and pastes it into the destination point
The advantage is that you can use it on an empty layer blended “darken” or ”lighten”
and limit the effect, getting good looking results.
The disadvantage is that you can’t “clone” only texture.
This process used to be done with default photoshop “High pass” but since the filter’s
algorithms are optimized to work “faster” as opposed to be totally accurate.
In this chapter we will also overcome this inaccuracy.
When you split the image, you are able to select the exact amount of texture you wish
to work on later, when using the clone/healing brush tools.
• You can manipulate texture without affecting the shape and contour of the
• Using the right radius you can retouch on borders without getting blotches.
• You can correct tones/luminosity without altering the texture.
• A more accurate type of High Pass Sharpening.
• Reduction of Moiré.
Basically speeding up the process of healing/cloning, with a lot of control and several other
very useful applications. Keep in mind that this is just like “pandora’s box” being opened for
you. You need to experiment with it to find many its many other uses.
• Start with two copies of the image you want to separate (Stamp: command(Mac)/Ctrl (PC) + option (Mac)/alt (PC) + shift + “E”).
Name the top copy HIGH and the bottom layer LOW.
• Place both layers inside a group and call it SPLIT.
• Working on the LOW, run a gaussian blur (Gaussian Blur is the most common choice but you can get great results with any kind of
blur) ilter at the intended pixel frequency
The RIGHT radius is the one that blurs the texture you want to keep/maintain/manipulate afterwards.
• Working on the HGH, choose Apply Image (Shift+Ctrl+A on PC; Cmd+Shift+A for Mac)
Settings for 16 bits:
Settings for 8 bits:
• Your HIGH layer will now look like a High Pass
• Set the Blend Mode to Linear Light. Opacity/Fill should remain at 100%.
Note: This technique is designed to end up, with a group that looks exactly as your
The only difference is that your image data is now separated into two frequencies:
HIGH containing detail and LOW containing shape.
What can you do on the HIGH layer?
• Using the healing brush (Hard edge to avoid blurred texture to be introduced – Always use a bigger brush than the texture you want to replace – “Current Layer” selected.) , but this time we are limiting, with a radius, the amount of texture sampled and the amount of tone/luminosity, used for the blending (blending texture with texture).
• Using the clone (Usually with soft edges – “Current Layer” selected) tool in normal and both darken and lighten mode. But now,
you’re only sampling the texture.
• Using the patch tool to replace texture.
• Clipping different curves – for different effects.
What can you do with the LOW layer?
• Create a new layer over it and paint in normal mode, on low opacity to even
• Create a duplicate of the LOW layer.
Blur it further to eliminate middle frequencies.
Mask and paint with white on the mask to reveal the effect where needed.
This is called “Band Pass” and it has a lot of variations.
The mot important part of this technique is that you can experiment with it. Do it!