Frequency decomposition in Photoshop. Photoshop Lessons for Beginners

This article is for Dummies. In it, the method of frequency decomposition is described in as much detail and detail as possible and an attempt is made to answer the main questions about this. In addition, the article inserted chips and lifhhaki not only for retouching photos in Photoshop, but also in general for working with the program.

Introduction

The frequency decomposition in Photoshop raises many questions. And if two years ago there was little information on this matter, now there are of course answers on the Web, but they are all fragmentary and not always clear. It is because of this that newcomers understand the frequency decomposition in Photoshop is difficult.

Tutorials from professionals on the Internet are given for a reason. Many companies expose to the vacancy of the retoucher requirement to know how to make the frequency decomposition in "Photoshop" at least at the minimum level. But even freelancers technology will come in handy - will increase both speed and quality of work.

What it is?

Frequency decomposition is the expansion in frequencies. The term is used not only in the field of portraits, but also in mathematics, music, etc. For a retoucher, this means that the photo is laid out on several layers (frequencies), for example, a layer of details and a layer of tone, each of which is edited separately from the rest.

Since this article is included in the "Photoshop" lessons for beginners, it will pay attention to both directly explaining the principles of frequency decomposition, as well as the little things that professionals have long known.

History

Computer graphics and processing is based on mathematical laws, although creators sometimes do not care about them. Thus, the frequency decomposition went from the Fourier expansion to the frequencies: first the mathematical method was borrowed by radio engineers, then the musicians and finally the retouchers.

The lessons of "Photoshop" for beginners rarely contain this information, and in mathematical formulas there really is no need. However, what the frequencies represent, it will be considered a little further.

Why is this necessary?

The frequency retouch is applied in cases where it is necessary to process the alu naturl. In other words, if the end result should be a natural, rather than a glossy treatment. Also processing in the manner described below is much more accurate and qualitative and means the highest degree of skill.

Difference from the usual ways of processing

Glossy retouching of photos in "Photoshop" is carried out with the help of masks and various types of blurring. This makes the skin on the portrait too much soapy and "it is seen that it is processed". For certain formats, this result is desirable, but in the case of natural portraits, processing should not be visible. This is done by separating the layers from each other - retouching one of them, we do not touch the others.

Is it only possible to use portraits?

Of course, the taboo "to use only for strokes" for this technique is not. And although on this, and for a number of other articles on the Internet, you might think that it is for them that it is most effective, it is not so. Portraits make up the lion's share of the photography market, and their retouch always comes first, but the frequency decomposition is universal and perfectly suited for any images where there is a need to edit the details separately from each other.

How many frequencies to lay out?

There are two types of frequency decomposition in Photoshop:

1. The skin is decomposed into two frequencies - tone and detail. On the first layer the skin is smoothed, on the second the defects are removed (wrinkles, pimples, etc.).
2. Decomposition is performed at three frequencies - high, medium and low. We will consider in more detail below.

First steps

Regardless of which method it is decided to use, you first need to open the photo in Photoshop and make several copies of its layers - the amount depends on the method. In the first case, two copies of the layer are created, in the second case two.

Frequency decomposition in "Photoshop" into two layers

As already mentioned above, as the first layer for this method, the skin tone is taken, as the second - details.

After creating two copies of the layers, it is recommended that they create a separate layer group for them. This is not necessary, but it is considered a good form for retouchers and generally simplifies the work. Groups in "Photoshop" - a piece of professionals.

Also for convenience of work it is recommended to give appropriate names to layers: "Tone" and "Details", and "Details" have above "Tone".

Next, photo retouching in Photoshop begins in the usual mode: open the "Tone" layer and apply "Gaussian Blur" to it.

Blur values usually range from 7 to 10 (the higher the number, the larger the image, in some cases it can be up to 15). The exact number is selected by the retoucher independently - depending on the size of the photo and the eye. Ideal blur - when the skin is smoothed out, but the shape and basic details are still read.

Then go to the second layer. It must be prepared in advance. To make all the details "cut", the filter "Color Contrast" is used. In "Photoshop" English-speaking sounds like High Pass. It is located in the Filter menu (Flter) - Other (Other). In general, this article describes the frequency decomposition in "Photoshop" step by step in Russian, but those who use the program in English will also be useful.

The sharpness of "Color Contrast" can be adjusted in the same way as "Gaussian Blur". The value is the same - if the number 12 is selected for the "Tone" layer, for "Details" it will be equal to 12. The result of applying the filter is a gray relief image.

Second phase

For the Details layer, the Overlay Mode is changed to Linear Light. If the image is too contrasty - go to the Curves tab and reduce the contrast. Alternatively: Reduce the contrast "in the old manner" by reducing the "Contrast" parameter.

In itself, the frequency decomposition has already been done - it remains only to remove defects with the help of a dotted brush. This is a simple, but painstaking work. The brush is recommended to take a small one with a slightly flattened shape (is set in the parameters). She needs to walk around the entire image and remove the defects.

Attention! By removing small pimples and facial wrinkles, you should leave those lines that make the photograph anatomically correct and affect the similarity to the faces in the portrait.

Remarks

The simplest technique is described, but there is one more variant of this technique. In the following way, you can perform the frequency decomposition in Photoshop CS6 and above.

When working with the "Details" layer, instead of the "Color contrast" filter, go to "External channel" (Image tab), in the parameters from the drop-down list, select the "Tone" layer (this is not a typo, choose "Tone") and click Ok.

The Overlay mode is then also changed to "Linear Light." All the following actions are performed in the above described order.

Important! If the "Gaussian Blur" is uneven, and the larger value of the parameter is too "blurring" the details, you can blur the second time uneven areas using the "Lasso" tool. It is able to allocate the necessary parts of the image, after which the blurring is applied only to the selected areas.

Decomposition into three frequencies

The frequency decomposition into three layers in "Photoshop" is made according to the same rules as for two. On the other hand, the three-layer expansion is closer to its pre-decomposition of Fourier, and with it it is easier to explain the principle of decomposition itself.

So, the basis is taken by the upper, middle and lower frequencies. In the area of retouching, information about the general form appears in the upper frequencies, in the medium - surface texture, as well as all defects and spots, in the lower - information about light and transitions. After this description, it is not difficult to conclude that the layers "Tone" and "Details" are nothing other than upper and lower frequencies.

The middle frequencies in the above described method merged with the high ones and were edited independently, therefore the method of frequency decomposition into three layers is much more correct and qualitative. Consider it.

Frequency decomposition into three layers in stages

Before the decomposition, it is necessary to pre-process the photo. It is recommended to create one copy of the layer for this.

Interesting! A copy of the layer can be created by clicking the mouse from the desired item in the context menu or by clicking on the corresponding icon at the bottom of the layers window. This action is also performed using the Ctrl + J key combination. Combinations of keys are of great importance in the work of "Photoshop", they accelerate it and make it more comfortable. Of course, at first the combinations will not be remembered and will not be used on the machine, but enduring the transitional period of memorization in order to become a master is worth it.

Defects are removed on a new layer with a dotted brush. This is less laborious work than in the last paragraph, since there is no need to remove trifles - in this case the size of the brush is taken larger and only what is really immediately evident and will interfere with the subsequent work is processed.

Then three copies of the processed layer are created. Called respectively "High", "Middle" and "Low". This is done, as was said before, for convenience. You can start retouching both from high frequencies and from low frequencies, - it makes no difference.

In this article, let's go from top to bottom, that is, start with "Low".

On the "Low" layer, "Gaussian Blur" is superimposed. In contrast to the method of decomposition into two layers, the blur parameter can reach up to 30. The main thing is to choose a number at which the skin tone will be uniform.

For the "High" layer, the "Color Contrast" filter is selected. The value of "Color Contrast" should be three times less than "Gaussian Blur".

Lifak: record the values of the parameters of the layers in their name. If the numbers are 30-10, they are easy to remember, but working with 12.7, it is better to write down all the same.

The "Low" layer will contain both blur (blur) and contrast. Blur value is equal to the value of "Color Contrast" in the "High" layer (in the example, 30), and the contrast value to the blur value in "Low" (10).

A group is created for all three layers. Decomposition is ready, you can start editing.

What is needed for each of the frequencies?

The "Medium" layer contains all the defects. It is completely undesirable to delete it. To remove the unevenness, you need to create a mask (Alt + icon of the mask in the bottom of the window of layers), and then use a black brush to draw along the portrait in places where there are irregularities.

In the same way, you can process the "High" layer to increase the uniformity of the skin tone. On the same layer they work with the color scale - they darken and tint the necessary areas, smooth out the colors.

Application possibilities

In addition to studio portraits, in which it is required to remove a couple of pimples, before retouching, the method of frequency decomposition in "Photoshop" will set quite different goals. So, it can be applied in such cases:

1. It is necessary to fix the clumsy work of the make-up artist - in other words, to remake the make-up. It is also possible to apply makeup from scratch. In the latter case, it is recommended to have a photograph of the same model with any other make-up for the reliability of the application.
2. Soft muffling of the texture of the skin - easy and accurate retouch, without the intervention of a dotted brush and a "soaped" blu.
3. Shave a man - you need a combination of methods of frequency decomposition, with painstaking work you get a good result.

Speed of work

Despite the fact that the method seems simple, after the decomposition itself is completed, the work on all three frequency layers continues to be painstaking. An experienced retoucher is working on such "small things" as shadows and glare, the volume of the image. Frequency decomposition is not a way to transform a photo in one click, but, conversely, the technique of its deep processing.

Nevertheless, the mathematical basis of the method suggests how it can be automated.

Software Methods

For "Photoshop" (and for "Gimp", his "Linux" brother, by the way, too) there are special plug-ins, as well as action games. All of them do not automatically automate the retouching of the photo (in the end, it's still a creative process), but they perform the actions programmatically to create the necessary layers and their settings. This greatly simplifies the frequency decomposition in Photoshop.

Action (action - action, operation) is a file with the extension ANT, which is a set of operations in "Photoshop". It can even be called a mini-program. An existing action file is opened using the "Window" tab - "Operations".

You can create an action for frequency decomposition yourself - manually perform all of the above actions and go to the same tab "Operations", and then click on the icon for creating a new operation. For convenience, it is also recommended to create several actions for creating separate first, second and third layers.

Actions for downloading are available on Internet resources, however it is recommended to create them yourself - first to try the frequency decomposition manually, then to understand how to use it, and then automate this process for later use. In addition, downloading from the Internet always involves the ability to download the virus. So it's better to be safe.

Like any program, actions are available for editing, and editing what was written by someone else is more difficult. To the fact that each author makes an operation, above all, "for himself," and only then, in a burst of generosity, puts it on the Internet for everyone to see.

conclusions

In general, frequency decomposition is a very powerful tool. The first method, in which the process is performed in two layers, is more approximate to the usual retouching and only slightly reveals the veil of using decomposition. The second, representing a modified mathematical operation, gives a huge scope for creativity. The article described the minimal possibilities of use, since its purpose is to tell about the decomposition itself, what it represents and how to do it. And getting deeper into the topic a little more, you can find much more "chips".

Finally, it should also be said that one possession of a frequency decomposition will not make anyone a genius retoucher. Like any instrument, it has power only in experienced hands. So, you need to see the final result before you take the first step, notice the little things and only then choose which tools are best to fix them.