The Rays and shadows of PS synthesis techniques

Shadows are particularly important in photo synthesis, as long as there is light there will be shadow, the correct treatment of light and shadow, you will find that the image you synthesized in an instant to upgrade a big grade. This tutorial will share some techniques for dealing with light and shadow in compositing.

The first is a theory that helps you understand how light and shadow work, and then teaches you exactly how to deal with shadows in practical applications.

Light source and shadow angle

Before you do any image processing, first determine if you need a shadow, and then determine the direction of the main light source.

As shown above, you will find that the light source in the original photo is in the upper left of the heroine, so you should follow the direction of the light source, and in the final synthesis of the photo the source of the light is in the top left of the heroine. Some of the elements in the photo can be used to find the direction of the light source to guide the process of lighting in the synthesis. Here's a similar example. But this time the light source direction on the right, the designer uses the same processing method, in the synthesis although changed the scene, but still follows the light source from the right, the shadow on the left.

However, sometimes there is no obvious light source as a reference, at this time can use the object in the scene projection to determine the direction of the light source. Here's an example:

The road sign in the original photo has no shadow, it doesn't feel real, so we're going to add a projection to make it look real, there is no obvious light source in the picture, but you can see the man and the girl in the picture in the right rear of the character, so that the projection of the Signpost should be in its own right rear, as shown below:

The above is just the foundation of the theory, below I will teach you some of my skills to deal with light and shadow, for the convenience of understanding I give different shades of different names.

1, contact Shadow

I call this shadow "contact Shadow" or "Touch Shadow" because I don't know what name it is. Haha, this is a very important shadow that can tell us that the object is placed on the ground or close to a surface, and that the position of the statue in contact with the ground is such a shadow, This shade is darker, but not pure, and has a certain degree of transparency and edge softness.

It's easy to make this kind of shadow in Photoshop as long as you practice, as in the following example I put the model from the original photo into a new synthetic scene, you can obviously feel the picture is very dull, no shadow model looks like floating in the air.

Let's give him a little bit of shadow to try, as shown in the following figure, set a medium size brush (depending on the size of the picture), hardness of about 30%, transparent about 25%, front color black, and then at the edge of the object to draw, from inside to outside of the drawing.

Now look at the picture below, is not feeling the model is standing on the ground:

2, soft Shadow

This kind of shadow is a particularly important shadow that can make your synthetic reality a notch. And you have a greater degree of freedom in drawing this shadow, just set a softer brush, 25%-40% intensity, and draw around the object. Remember that the opacity of the shadow gradually fades from object to distance.

As shown below, I use a large soft, low transparent base (around 20%) to draw a shadow around the object, you can see that you can't tell the shape of the girl's shadow, because it's too blurry, but it definitely adds to the reality of the scene, and notice how the shadow fades away from the body part to the distance.

3. Projecting Shadows

This if you want to create a more authentic effect, you're going to have to learn another shadow, projecting a shadow that is projected onto the ground or other surfaces as a result of an object blocking the light, so the shadow is greatly influenced by the shape of the object, and in Photoshop we generally use the shape of the object directly to make this shadow.

Creating the same effect in Photoshop can be accomplished in a number of different ways, depending on which method you are accustomed to or like, and simply introduce several ways to quickly create a cast shadow:

Method One:

As shown in the following illustration, copy the tower layer and then use the hue/saturation command to reduce the visibility to zero. Then change the command to flip position adjustment and deformation, add a bit of Gauss blur, appropriate adjustment of transparency, and based on the principle of fade from near to far shadow, with a mask or eraser to make appropriate adjustments on the OK.

Method Two:

This method is particularly fast, and many people do not know that you can use layer style separation to quickly make projections. Open the Layer style panel, add a projection, adjust the parameters to get a soft edge projection, where you can adjust the transparency of the projection, you can also control the opacity of the layer after the separation of its transparency. When you are sure to right-click on the layer style symbol on the right side of the layer, select Create layer to separate the projection you just set on the separate layer, and then you can change the position and transparency like method one to achieve projection production.

There are a lot of ways to make projection projections, and there's not too many examples here, and you're doing it the way you're best at it. Now let's talk about the technique of light processing.

4. Projecting Light

The production of light effects is particularly important in synthesis, which can greatly enhance the authenticity of the synthesis. Here is a look at the following image of the production method of the light effect.

It's not hard to make light effects in Photoshop, just use a good layer blending mode. Do not fix the thought that an effect is on a layer, in fact, mixing between layers can produce a lot of interesting effects.

To create a light source first, create a new layer, the foreground color orange, use a large soft brush in the lamp position point a soft point, and then change the layer blending mode, you can try one by one, try which mode out of the effect of choosing which, this is not fixed, sometimes this pattern is suitable, Sometimes another pattern is more appropriate, depending on the situation.

Remember that the blending mode is related to the brightness value, if all the patterns have been tried or not as you expect, try a darker, less saturated color, and in this case I'm using a dark yellow glow.

Next we use the filter > Render > Lens flare to make glowing light. Make a rectangular selection, create a new layer filled with black, add a lens flare filter, place the glow in the center of the rectangle, and then adjust the color with hue saturation, and then change the blending mode to "filter" so that the black part will be filtered to the remaining Halo, as shown:

When the light source is made, consider the light effect of the position of the scene where the light source may be affected, so as to increase the sense of reality, the same as above, using a large soft brush to draw and then change the layer blending mode.

I've found that the mixed patterns of color Dodge, light, and linear dodge are especially common when it comes to making light, but as you've said, it's also influenced by color and brightness, so the reality of the light effect depends on where you put it.

As can be seen above, the ground adds a lot of realism after the light effect, here is a large soft yellow brush painted a point, and then color Dodge Mixed mode, and then use the deformation tool to flatten the ground, the same light on the left side of the wall can also be used in a similar way, we have to try, Anyway, the idea is such a thought, more details on their own to try to add a try. As shown in figure:

5, Contour Light

The following describes a light, when the light comes from one side of the object or from the back of the object will be on the edge of the object to form a bright light effect, called contour light, many photographers will use this contour light, to the subject to create a mysterious, beautiful feeling. The simple way we use the layer style to make this light, add some inner shadow, and then change the blending mode (note that the inner shadow here is the name of the layer style, not the name to limit your thinking, in fact, the inner shadow can change the color, it is not only can do the inner shadow, Clever use of it can make a lot of interesting effects, such as UI design often use white inner shadow to do high light and so on. Of course always use the same blending mode is not always useful, you need to try different blending mode to make the most suitable effect, anyway, the goal is to create contour rays at the edge of the object.

The color of the light depends on whether the scene you synthesize is day or night, and if you use a Dodge or light blending mode, you must use dark colors, because these blending modes will brighten them up. This is a constant trial and error process, until you find a suitable color and parameter values (of course, the practice is much more natural you know the approximate, tune up quickly), in addition, some effects do not necessarily do very strong, the effect is a little change small effect added, so pay attention to detail, attention to the subtle effect of production, It may be a very small, very faint effect that can add a lot of points to your synthesis. Patience and carefulness are the most important.

I made a quick setup to illustrate what I just explained. This is just a rough setting, look at the image below and add a little bit of the inner shadow set in the figure above.

Here's a similar example, look at the position of the arrow in the picture, candlelight from the front of the model face, we will see from the side of the model side face contour will be very bright, so here we give the model facial contour added a very bright light, looks very real.

Of course, use the inner shadow inside the layer style to make the outline light is flawed, sometimes in places you don't want to add. I usually increase the distance settings, change the angle to match the direction of the light source, but even so, there are often unwanted effects appear, increase the size setting, you will get a smooth effect, but only a little weak light line. Look at the picture I made some adjustments that would look a little better.

From the above you can see that there are a lot of people do not want to appear in the effect, please see my white circle out of the place. How to get rid of this global impact, so that the effect is only where you want to appear, because this is the layer style, so you can not use the eraser to erase directly. I thought for a long time and then I found a solution.

Method is to detach the layer style, it's kind of like the way it casts shadows above, after adjusting the effect, the following figure right click on the layer style, select "Create Layer", the layer style will separate into several layers to display the effect just created, this time you can control each layer separately, You can add a layer mask to the inner shadow layer with a black brush to cover the place you don't want it to appear, or directly with the eraser can also be deleted (the proposed mask, slowly you will know this is better than the direct deletion, because later can be modified, but deleted words will not be changed). The method is this, the careful adjustment effect will become good.

Of course, this is only one of the methods, or skills, different people have different habits, many people are actually directly painted up, lazy to adjust the layer style, with the most suitable for your method to make the same effect on it.

6. Global Light

The last kind of light effect is the global light effect, this kind of light effect is the picture on a whole, global range of light sense, adjust the overall atmosphere, so called global light effect. This light effect is relatively simple to produce, and the light effects filter can be made quickly. I usually add this effect to the picture in the final step of completing the entire synthesis. Because this can be at the end of the overall picture to find a unified light and tonal, so that the picture will look more comfortable, this step of the operation will let you have done before the steps plus a lot of points, the overall synthesis effect of a big difference, to upgrade a very large grade. Select the filter-render-lighting effect parameter settings on the menu depending on the specific picture, as shown in the following figure:

But to remind you that this type of filter directly on the picture is a destructive edit, it is recommended that you copy a layer and add an effect to the copied layer before adding the filter, so that if you regret it later, you can edit it again. In addition to teach you a master of the common skills, is the use of smart layers, the layer first converted to a smart layer and then add a filter, if the results are not ideal, you can also adjust the parameters. The method is to right-click on the layer and select "Convert to Smart layer".

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