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Photoshop: Add a Realistic Rainbow to Your Photograph 1

Rainbow Colors

The rainbow spectrum is commonly known as the Newton mnemonic, Roy G. Biv, which stands for red, orange, yellow, green, blue, indigo, and violet.

In a primary rainbow, which is the type we typically see, the spectrum begins on the outer edge, meaning the outermost ring is red and the innermost ring is violet. If your intention is realism, this is the order you should use.

The Rainbow Scape

You can learn all about the conditions under which rainbows, and artifacts, are seen, at About Rainbows. Below is my interpretation of that information as it is applicable to a rainbow artist.

• Rainbows occur as a result of light being refracted through a continuum of tiny water droplets in the sky. So while you have free artistic license, consider that real rainbows require a moist sky.
• The center of a rainbow is always opposite the sun, with the observer standing in between. As a result, the sun is rarely visible in photographs where rainbows are seen. These image results can confirm this little realized fact.
• A rainbow seen from the ground requires a low sun, or else a high vantage point, such as a mountain top. With the sun straight above the head, the light source is too high to produce a rainbow visible from the viewing angle.
• Rainbows are full circles, but the ground hides the bottom half. A circular rainbow can only be seen from an altitude at which the ground does not interfere, such as from an airplane. See these image results.
• Moonlight can also create a rainbow, but the effect is typically minimal.

Making a Primary Rainbow

Here is an image I grabbed from SXC.hu.

This is a free image, so you can save it, by right-clicking it, and then load it into Photoshop. You can also download the original full-sized image here, but I recommend working with the compact one above for the purpose of following this tutorial since everything will render much more quickly.

Create the Rainbow Layer

With the image loaded into Photoshop, click the Create a new layer button. You'll get a new layer named "Layer 1." Double-click directly on the text and change it to "Rainbow."

Prepare the Gradient

Select the Gradient tool as shown to the left. If you are seeing the Paint Bucket tool instead, click on it and hold your mouse button down for a second to call the pop-up menu, and select the Gradient tool from there.

With the Gradient tool active, look toward the top of the screen at the gradient options. Be sure that the first box is selected, which is the Linear Gradient option. Then click in the middle of the gradient panel directly to its left.

This will open the Gradient Editor shown below. Select the Transparent Rainbow, which is in the 6th column of the 2nd row. By default, orange is missing from this color set. But that's ok since the red and yellow will create it. Feel free to play around with the color stops if you'd like. Then click OK.

Create the Basic Rainbow Circle

With the Rainbow layer active and the Gradient tool selected, click near the bottom of the image, drag your mouse about a half an inch up, holding Shift to create a perfectly straight line, and release. This will create an upside down gradient with red at the bottom of the stack, as shown below. We will turn it right side up in the next step.

Then go to Filter > Distort > Polar Coordinates.

This will open the following window. Zoom all the way out if you want to see the preview. Then be sure Rectangular to Polar is selected, as shown below, and click OK.

We will wind up with something like the following. Notice the rainbow spectrum is now unreversed, with red correctly on the outer edge.

Hit CTRL+T to call up the Free Transform mode, as shown below, and drag the outlines to resize the rainbow to your preference. Then hit Enter to accept. Don't worry about pixelation, as we're going to blur the rainbow shortly.

Free Transform can also be accessed through the menu; Edit > Free Transform.

I made my rainbow slightly wide.

Blend the Rainbow into the Ground

With the Rainbow layer still active, click the Add layer mask button, as shown to the left. This will place a blank white thumbnail next to your Rainbow thumbnail.

What a layer mask does is it allows us to hide, or mask, parts of a layer without changing the layer itself in any way. In a basic scenario, we'd do this by painting on the layer mask with black, which will hide the corresponding areas of the actual layer. Painting on it with white will reveal the corresponding areas again.

The benefit is if we make a mistake, we can simply white out the mask or delete the mask altogether, and the original layer will remain untouched throughout it all. It's a great way to ensure we are not permanently damaging our original image.

Since we need to blend the rainbow gradually into the ground, we will apply a white-to-black gradient on the layer mask into the direction of the ground.

Select the Gradient tool again, and put the gradient back to its default color set.

For this, we can use the dropdown arrow as shown to the left and activate the first gradient, which uses the foreground and background colors currently selected.

Also revert your foreground and background colors to white and black respectively by pressing the D key. Then click on the mask thumbnail to activate it, and create a straight gradient from around the midpoint of the rainbow to the point in the ground where you want the rainbow to completely disappear.

Notice the gradient we just made now appears in the mask's thumbnail.

Add Realism to the Rainbow

You'll immediately see a wonderful difference upon changing the layer mode to Screen.

But it's a little bright and surreal, so reduce the opacity to around 70%.

Now we want to blur it ever slightly. Click on the rainbow thumbnail itself to be sure it, and not the mask, is active. Then, from the menu, go to Filter > Blur > Gaussian Blur, and enter a radius of around 1.2.

Finally, as is the case with most rainbows, we'll brighten the sky inside the rainbow. Since we did not actually erase any of the original rainbow circle, by using a layer mask, we can create an accurate selection of the interior of the rainbow with the Magic Wand, shown to the left.

Click on the Rainbow layer to activate it. Then with the Magic Wand, click anywhere within the interior of the rainbow. This will create a perfect circular selection.

Create a new layer and name it "Interior." Then with the Paint Bucket, fill the selection with white, and hit CTRL+D to deselect.

Now we want to blend this into the ground just as we did with the Rainbow layer. For this, we can simply duplicate the Rainbow layer's mask and apply it to this Interior layer.

To do so, with the Interior layer active, hold CTRL and click on the Rainbow layer's mask thumbnail. This will create a rather rectangular selection, which is a result of Photoshop being unable to show us a gradient selection; despite what we are shown on the screen, the selection is indeed a gradient selection.

Now click the Add layer mask button. The Rainbow layer's mask is duplicated onto the Interior layer.

Perform a Gaussian blur on the Interior layer with a radius of around 5 to blend out the perimeter, and decrease the opacity of the layer to around 10%.

Finishing Touches

At this point, I made some additional adjustments to my rainbow. Specifically, I made it wider and subtler, reapplied the Gaussian Blur to the Interior layer, and applied some additional gradient to the Rainbow layer's mask to create a more gradual blend.

Add a Secondary Rainbow

You can end it with that. But I felt this rainbow could use a friend, so I decided to add what's called a secondary rainbow.

A secondary rainbow is a concentric reflection of the primary rainbow that appears at a distance of about 1/4th of the radius of the primary rainbow outside the primary rainbow. Because it is a reflection, the spectrum is reversed, with the red ring inside and the violet ring outside. It is also about twice as thick as the primary rainbow and 1/10th as visible. Additionally, the brightening of the sky that occurs within the interior of the primary rainbow occurs outside the secondary rainbow, creating a subtle dark band of unbrightened sky, called an Alexander's band, between the two rainbows.

Creating a secondary rainbow in Photoshop is just a slight improvisation of the steps taken in creating a primary rainbow. So, given you've followed this tutorial closely and I hopefully explained the necessary details with enough clarity, you should be able to arrive at what I have as a finished product below.

Continue Reading:

• Add a Realistic Rainbow to Your Photograph 2
• Colorize a Black & White Photograph Image
• Smooth (Long-Exposure) Waterfall Effect
• Put a Realistic Camouflage Pattern on Textured Cloth
• Minimal Style Lightweight Drop Shadow For Images

Also See:

Categories: Photoshop

Tags: photograph . rainbow . realistic