Adobe Photoshop Tutorial. Copyright Michael B. Karbo.
New exercise: Water in the street
Now you are going to try to blend two pictures, so there will be gradual transition from one picture to the other. That can be done in different ways, but here we use a gradient as mask…
You will be blending 2 photos from Paris. The one shows a street (Rue de Verneuil), and the other is water from the Seine river. The idea is that the street needs to filled with water from the river, so it gets to look like a street from Venice …
1. Open the image file verneuil1.jpg from the home page for this booklet.
2. Open also the image file seine1.jpg. Select all in this picture, and make a copy (Control+a, Control+c).
3. Shift to the picture verneuil1.jpg (use Control+Tab), and insert the copy there (Control+v).
4. Close the picture seine1.jpg, you do not need that any more.
5. Use the move tool to place the water across the lower part of the street picture like here. You probably also have to move it a little bit to the left:
6. Rename the top layer to seine and the lower to rue. Save the image file as paris.psd.
7. Now you can say that there is water in the street, but there is way too much. You need to make a gradual transition between the two pictures. Select the layer rue, and insert a new layer by clicking on the button ”Create a new layer” in the bottom of the layer palette:
8. Rename the layer to gradient.
9. Now the layer gradient is selected. In a little while it will be used as layer mask in connection with the layer above. But first you need to make a gradient on the layer. The gradient needs to go from black to transparent. Select the Gradient Tool:
10. Press d to select the default colors, so the foreground color is black.
11. Then use the settings line to choose the color sequence Foreground to Transparent as shown below:
Now you are ready to place a color sequence on the gradient layer. color sequences are made by dragging a line between two picture positions. You have actually tried that before in this booklet (see page 43).
12. Now drag a line from somewhere above the bottom of the water picture. Drag it vertically up to somewhere below the upper edge of the water. If you hold the Shift- key down, you force the line to be vertical as in Figure 46.
13. Save the picture.
Figure 46. The color transition is dragged across the picture.
The color transition makes a mask
You have now made a color transition on the gradient layer, which was otherwise empty. If you remove the viewing from the other two layers, you can see the color transition (see Figure 47).
The color transition starts in the bottom of the picture, where the color is all black. It moves up, where the black color gets diluted, so it ends in pure transparency:
Figure 47. The gradient layer contains a color transition that goes from black toward transparency. This color transition can be used to to make a step by step blending of two pictures.
Now the color tansition has to be used to make a layer mask in the Seine layer. That is done in this way:
1. Hold the Control key down, and click in the gradient layer. That makes a selection, which includes all those pixels that are in the layer. The selection is seen as a dotted rectangle in the picture.
2. Now you have a selection, which is created based on the color transition. Select the seine layer.
3. Then click on the small button ”Add layer mask” in the palette Layer:
4. It works! A layer mask is created in connection with the layer. Notice that the color transition in the layer mask is actually the reverse of that in the gradient layer. The top part of the layer mask is black, so the upper part of the seine picture is hidden.
5. You can check the effect of the layer mask by holding the Shift- key down and clicking on the layer mask’s tumbnail in the layer beam. Then the mask’s effect is temporarily cancelled:
6. Click again, then the mask is activated.
7. A right click on the mask icon opens a menu with different options. If you want to remove the layer mask, you need to select Discard Layer Mask like here:
If the layer mask and with that the color transition was not satisfactory, it is easy to make a new one.
Start by removing the layer mask. Then select all on the gradient layer and delete it with Control+a and Delete. Then drag a new gradient, and use that in the same way as previously described. The gradient is the basis for the layer mask in connection with the seine layer.
Figure 48. The layer mask allows a gradual transition between the two pictures.
Use the brush in the mask
It is very useful and effective to use gradients in connection with layer mask. But in this exercise it just will not really do the job.
If the picture is going to look like a flooded street, you have to work on the layer mask, just like you did in a previous exercise (the image file calme.psd). Try that:
1. Close the viewing of the gradient layer (click the eye away from the layer beam).
2. Then select the mask by clicking on its thumbnail:
3. Now you are working in the mask. Select the brush tool by pressing b.
5. Now paint carefully in the mask. Remember that you reverse foreground and background colors by pressing x. When you use black color, you close the mask off:
6. Of course if you paint white, you get the opposite effect. Now use the brush with the colors alternately, so you get a smart picture of a flooded parisian street. Finally save the image file.
Figure 49. Now the water is flowing in Paris’ streets.