Lesson: Basic Atmospheric Effects in Photoshop

[Brickdoctor]

LEGO is a medium with which virtually anything can be built - oceans, landscapes, ships, castles, spacecraft and more. But now that you've created that great set for your brick flick or comic, you might be thinking, "What about the sky?". Yes, you could build a big blue wall and various clouds and celestial bodies to attach to it, but maybe you don't have enough bricks, or maybe you just don't like the way that looks, and you would prefer the simpler look of a sky and its atmospheric effects created in photo-editing. This will be done in this lesson using Adobe's Photoshop.

Prerequisites:

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• You'll need to know how to use your camera and how to take a crisp and well-composed photo with it. Photoshop is a terrific piece of software, but it can't completely fix an image that's out of focus, blurry, significantly grainy, poorly composed, or otherwise lacking. If you want to know, I shot my photos for this lesson with an entry-level DSLR, the Nikon D-3100, with a basic 18-55mm lens and an exposure time between two and six seconds and an aperture of f13.
  
• You will of course need Photoshop. This lesson was written using Photoshop CS5 Extended, but the techniques should work with other versions, though I have no experience with them. (I do know that the only features that CS5 Extended has and CS5 does not are 3D tools and image data analysis tools - you won't need them for the editing described in this lesson, so if regular CS5 is what you have, you're fine)
  

Contents:

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Preparation: Setting up to take the Photo

Daytime Effects

• Adding a Daytime Sky
  
• Adding a Sun
  
• Adding Daytime Clouds
  

Nighttime Effects

• Adding a Nighttime Sky
  
• Adding Moon and Stars
  
• Adding a Starfield
  
• Adding Nighttime Clouds
  

Adding a Sky to a White Background

Assignment

[Brickdoctor]

Preparation: Setting up to Take the Photo

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For this image into which I'll eventually composite a daytime blue sky, I've already got a light blue paper backdrop set up behind the set. It's not necessary to do this, but it'll make editing so much easier if you do. You won't have to worry as much about making sure that you neatly select and feather all those edges where the LEGO meets the sky, and you won't have to worry about properly coloring any tints or reflections affected by the color of the sky.

Also, I try to use lighting as close to the conditions of the final image that I'm trying to achieve. This means that for my daytime outdoor photos, I always take the photos in the middle of a sunny day, and the only lighting source is a large window off to the left. Then in PS, I always add the sun to the left half of the photo. If I wanted the sun on the right side, I would turn my studio setup around to get the window off to the right of the set. (or I could go with the lazy solution and just mirror the image in PS) The result? Realistic lighting, absolutely no Photoshopping required.

This lighting isn't as important during nighttime shots. In order to get a good exposure, it's usually better to start with a brighter image, and then darken it and add a (stronger) bluish tint in PS.

If you aren't able to set things up this way, that's okay. There's a section at the end of this tutorial that covers compositing using a white background. If you can, though, it's worth the little extra effort.

[Brickdoctor]

Adding a Daytime Sky

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Taking a good photo is beyond the scope of this tutorial, but once you've got one that you've satisfied, it's time to fire up Photoshop:

After you've opened up the image in PS, the first thing to do is to unlock the lone layer.

The layer appears in the bottom-right corner and will have a little lock next to its name. Double click the layer, and a dialog box appears.

The window is entitled, "New Layer", but, nevertheless, this box applies to the existing layer. If you want to rename the layer to something meaningful, like "LEGO", you can do so here. Otherwise, you can be lazy like me and just leave it as "Layer 0". (and you can always rename it later if you're getting confused by all the layers, of course)

Before you go any further, now is the time to make any tweaks to the colors of your image. I usually increase contrast a bit and adjust the blues (and reds if there're any red, brown or other warm-colored bricks) in Curves, and make the yellows brighter and more yellowish in Selective Color.

Now, to the sky. Switch to the Wand tool by clicking the little wand or by hitting the 'W' key.

Start by selecting a patch of the blue backdrop. You can always add to this selection, so don't worry if you don't get all of the background, and don't go crazy increasing the tolerance to try to select more of the background. (I've set my tolerance to 30 for this selection)

Now hold down the 'Shift' key while you continue clicking until the rest of the sky is selected.

If you catch a bit of the LEGO, like I did with the wall here right above the bucket, that's okay. Switch to the Lasso tool...

...and zoom in to the problematic spot. Hold down the 'Alt/Option' key while you use the Lasso to remove what you select from the existing selection.

Yes, I could go with a mask here or use the Pen tool to get more precise, but there's really no reason to do that when you're making an image for the web. (and remember, the edges don't have to be perfect when creating this sky, because the edges are already bluish from the blue backdrop) Just use the Lasso to clean up the selection where you need to.

Navigate to Select > Modify > Contract.

Contract the selection by a couple pixels. Now, my image is still at its original size, so the amount of contraction needed will depend on the size of your image. I've contracted by 2px for an image that's around 4000px wide, so you'll want to adjust that ratio depending on the size of your image. If your image is smaller than 1000px, I would just skip this step and move to the feathering step. If your image is around 2000px, I would contract by 1px, if your image is around 6000px, contract by 3px, and so forth.

Again, those edges are already bluish, so we don't need to cover them with this selection. Pulling back a little and then (as we'll do in a moment) applying a slight feathering to the selection will result in a better transition.

Navigate to Select > Modify > Feather.

Not too much is needed. Just a feathering of one pixel for me. Again, this amount depends on the size of your photo. If your photo is smaller than around 2000px, I'd go with 0.5px. If it's larger than the 4000px I have in my example, then go higher than 1px.

Feathering is just a blurring of the edges of a selection. This will smooth out the transition and make it more natural and realistic.

Click on the square displaying the foreground color to set it to a new color. This doesn't actually change anything in the image; there are just two colors there - one in the foreground and one in the background - for things that requires more than one color, such as gradients.

Set the foreground color to whatever color you want to use for the sky. I like #b0f0ff.

Now, create a new layer. (don't deselect the selection of the sky; we're just going to move to another layer before we fill it in)

Click the button that looks like a square with its bottom-left corner flipped up, and a new layer will appear above the old one.

In this new layer, go to Edit > Fill.

The only option you might need to change is the first drop-down menu.

Just make sure it's set to "Foreground Color". (which you've already set to your sky blue)

This will fill the selection with that sky blue color, and your sky should look something like this:

And that's your finished sky. At this time, I resize the image to 800px wide before moving on to the sun and clouds.

Adding a Daytime Sun

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Once you've got your sky finished, switch to the ellipse tool by clicking the shape or hitting 'U'. (you might have another shape tool loaded instead - just click and hold down to reveal the sub-menu or hold down 'Shift' while tapping 'U' to cycle through the various shape tools)

Set the foreground color back to white (#ffffff), and, in a new layer, draw a white circle. (hold down 'Shift' while drawing the ellipse to constrain it to a circle)

It doesn't matter where you draw it, as long as you aren't cutting off parts of the circle by drawing beyond the edges of the photo. If you don't know how big you want the sun to be, better to go bigger. You can always make it smaller later.

In the layers sidebar, click the button at the bottom with the 'fx' on it and choose 'Outer Glow'.

In the resulting dialog box, click the square with a solid color in it. (these glow settings were what I set as my default setting during a previous edit; your settings may not be the same, and you don't need to make them match at this point)

In the Color Picker, set a pale yellow.

Now, just fiddle with the settings of the glow until you're satisfied with it. I've set mine for a smaller and slightly concentrated glow that almost blurs the line between the white ellipse and the glow itself.

Apply the effect, and you're done:

Adding Daytime Clouds

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You've got your sky composited in, and you've added the sun, but perhaps this isn't a scene on one of those days with perfectly clear skies. Time to add some clouds.

In a new layer, set the foreground color to black and the background color to white. Since these are the default colors, you can also set them by tapping 'D'. Now, navigate to Filter > Render > Clouds.

Grayish clouds should appear over the entire photo. Next, go to Filter > Render > Difference Clouds.

And then render those Difference Clouds a second time. (you can repeat a previous effect by pressing Command/Control+F) The rendered clouds are unique, but you should have something like this:

Now, navigate to Image > Adjustments > Levels. (or use Command/Control+L)

Drag the little white arrow to the left to 'solidify' the clouds, and then drag the little grey arrow to the right to increase the black space between the clouds. There're no exact settings; just drag them back and forth until you've got something like this:

Now, in the layers panel, right-click on the layer with the clouds in it and select 'Blending Options'.

In the dialog box that pops up, change the Blend Mode to 'Screen'.

And now you'll see that the black areas have become transparent, letting the rest of the photo underneath show through and leaving only the white clouds on top.

You probably didn't get all the clouds right where you wanted them, so use the Lasso tool to loosely select one of the larger clouds that you want to move.

Now navigate to Edit > Cut (or Command/Control+X) to remove it from the layer, and go to Edit > Paste (or Command/Control+V) to place it in a new layer.

That's going to leave a big ugly chunk of clouds on black in the middle of the photo...

...but that's okay. Just change the Blend Mode of this new layer to Screen and all the black will disappear.

Use Edit > Transform > Rotate to reposition the cloud.

The cloud will appear in the middle of a box with squares along its edges.

Click and drag the squares to rotate the layer, and click and drag inside the box to move it around. Once you've got the cloud repositioned to your liking, press 'Enter'. Repeat this cutting, pasting, and repositioning for all the clouds that you want in different places.

Now, in the layers panel, set all but one of the cloud layers to invisible by clicking the eyes next to the layers.

With the remaining visible cloud layer selected, click the button at the bottom with the white circle in a grey box to add a Layer Mask to this layer.

Click on that white layer linked to the cloud layer to edit the mask. Layer masks basically turn everything you paint black invisible, while everything painted white stays visible. So, switch to the Brush tool.

And in the top bar, open this drop-down menu to choose a specific brush.

I like to just use a large, soft, basic brush for this, like the default soft 100px brush.

Now, just brush over all the cloud that you want to get rid of in this layer, switching to a smaller brush if you need to get into smaller spaces between clouds:

Set the next cloud layer back to visible, add a Layer Mask, and brush away what you don't want. If you mask over something you wanted to keep, change the foreground color to white and use the brush to make parts of the layer appear again. Repeat this for all the cloud layers.

And that's your finished daytime sky, with sky, sun, and clouds.

[Brickdoctor]

Adding a Nighttime Sky

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The process for adding a nighttime sky is almost the same as that of adding a daytime sky. (I recommend you read through that if you haven't already) Start in Photoshop with an image like this:

Again, I've used a piece of paper of the same color that I want to 'shop in, just to get the right tints and reflections.

The first thing you've got to do is adjust the image in Curves to get the lighting right, so go to Image > Adjustments > Curves. (or Command/Contrl+M)

Darken the darker areas of the image by clicking on the black line around the lower left quadrant and dragging it down and to the right. Then darken the lighter areas of the image by clicking the square that'll already be on the line at the very top-right, and drag it down.

Increase the blues of the image by switching the drop-down list labeled 'Channel' from 'RGB' to 'Blue'. Click the square already on the line at the very top-right, and drag it to the left. You can also decrease the Green or increase the Red, but you don't have to.

Now, switch to the Wand tool and start selecting the sky.

Remember, hold down 'Shift' to add to an existing selection if you don't get it all in one click, don't keep increasing the tolerance to try to get it in one click. I've got my tolerance set to 10 for this. As with the daytime sky, if you select any of the LEGO, switch to the Lasso tool and hold down 'Alt' while selecting to remove from the selection.

Now, with this nighttime sky, we want to make sure we get rid of any lighter edges on the LEGO, so we're going to expand the selection instead of contracting it. Go to Select > Modify > Expand.

And expand by a few pixels. As with the daytime sky, I'm doing this with my photo at its original size, so if you have an image smaller than the 4000px I'm working with, expand by fewer pixels, and if your image is larger, expand by more.

And then go to Select > Modify > Feather...

And I'm feathering by 2px. Once again, if your image is smaller than 4000px, feather by fewer pixels; if it's larger, feather by more.

And navigate to Edit > Fill.

Just make sure that you're filling with the foreground color. (and that should by default be set to black, but check to make sure it is)

And that's your finished night sky. This is the time when I resize before adding any other effects.

Adding a Moon

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With the foreground color set to white, start by drawing a circle in a new layer with the Ellipse tool. (hold down 'Shift' to constrain the proportions to those of a circle)

If you want this to be a crescent moon, switch to the Elliptical Marquee tool and draw a circular selection of about the same size - a little larger is good.

Click and drag inside the selection to move it to overlap with the white circle.

Then use Edit > Cut (Command/Control+X) to remove the selected portion of the circle.

Now, in the layers panel, with the layer with the moon in it selected, apply an Outer Glow.

Click the square with the solid color in it to change the color of the glow if it's not already white. (I've still got the glow from the sun set to default)

Change the color to white.

And adjust the settings for a small, faint glow.

Which gives you your finished moon:

Adding Stars

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Adding a star shape could not be simpler. Just switch to the Assorted Brushes.

PS will ask you if you really want to do that; click 'OK'.

And pick one of those crosshatch brushes. Use that 'Size' slider at the top to adjust the size. I like to vary my stars between 10px and 20px.

You'll notice that the brush is rotated so that the points are diagonal instead of horizontal and vertical, so place the stars in a new layer on a slope like this:

Then navigate to Edit > Transform > Rotate...

...and reposition the stars.

Press 'Enter', and your stars are completed.

Adding a Starfield

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I personally prefer the simpler, almost more cartoonish look of the stars created with the Brush tool - they seem to have more of a 'Legoish' quality than this starfield does, at least outside of sci-fi scenes in space - but if you want a quick and easy way to generate realistic, randomly placed stars, this is it.

Start by switching back to that layer that you filled partially with black to create the night sky.

Navigate to Filter > Noise > Add Noise.

Apply 100% noise. Set the Distribution to Gaussian, and make sure that you've checked 'Monochromatic', otherwise you'll end up with a bunch of very colorful stars.

That'll give you something like this:

Now, apply a Gaussian Blur of 0.5px to soften things up.

And just one more step: in Levels, drag the grey slider almost all the way to the right. You can adjust this based on your personal preference - dragging further right will decrease the amount and size of the stars. (and not dragging it as far will increase the amount and size)

And that's it!

You can also use Curves to apply a bluish tint to your stars or use the Brush tool with the foreground color set to black to get rid of some of the stars if you don't like where they ended up.

Adding Nighttime Clouds

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Clouds at night start off the same way as clouds in the day do: with the palette reset to the default colors and in a new layer, go to Filter > Render > Clouds, and then use Filter > Render > Difference Clouds, twice.

Now, open up Image > Adjustments > Levels (Command/Control+L).

This is when things start to differ a little from the process for creating daytime clouds. For these nighttime clouds, the only adjustment we're going to make in Levels is to drag that grey slider to the right, increasing the black spaces between the rendered clouds.

That should give you something like this:

Now, as you did for the daytime clouds, right click on the clouds layer, go to Blending Options, and change the Blend Mode to Screen. The black spaces will turn transparent, leaving you with this:

Using the Lasso tool, select a cloud (or group of clouds) that you want to move.

Copy that selection (Command/Control+C) and paste it (Command/Control+V); the selection is automatically pasted into a new layer. Then rotate it into position as you did the daytime clouds.

Because of the difference in the way the clouds were adjusted in Levels, these clouds are a little darker and are more wispy, which is good, but they've also turned out bigger, which we don't want. So, go to Edit > Transform > Scale.

A box with small squares will appear around the contents of the layer, just like it does when you use Rotate. Drag the little squares in order to adjust the size of the cloud. (hold down 'Shift' while you do so to preserve the original proportions of the layer)

Press 'Enter' to finish the transformation. By the way, one of the things I like to do when adjusting the placement of my nighttime clouds is to put the biggest, brightest ones over the moon or one of the larger stars. It's a little thing that adds a touch of realism to the scene.

Once you've cut out, pasted, repositioned and resized all the clouds, you'll need to clean them up, just as you did with the daytime clouds. Set all but one of the cloud layers invisible. Add a Mask to the sole visible layer, switch to the Brush tool, and use a soft brush to mask the portions of the clouds that you don't want.

Repeat with the other cloud layers, setting each one back to visible before you edit it.

And one last thing to finish this up. In the layers panel, click on the drop-down button labeled 'Opacity', and drag the slider to the left.

Do that with all the cloud layers, and your clouds are done:

[Brickdoctor]

Adding a Sky to a White Background

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Working with a photo that already has the correctly colored backdrop is always going to be easier, but sometimes that's not possible. If you don't have the appropriately colored paper/cloth/backdrop or if the set is too big (I needed to resort to the white backdrop for the Photoshopped title image in my review of the Kingdom's Joust - two pieces of blue paper can't cover the background of that set), then it's time to turn to the good ol' white backdrop.

Once you've got a picture opened in PS and the colors adjusted, use the Wand tool to select the background just as you would for the other colors of backdrops. Taking a good picture is, again, not the purpose of this lesson; nor is achieving that clean white background. Nevertheless, I will say that what you're looking to do when you first adjust these white background photos is good contrast between the subject and the background, and as bright and as uniform a background as you can get without blowing out the subject. In Curves, I typically start by clicking on the line in the bottom-left quadrant and dragging it down and to the right, which will darken the darker areas and increase contrast. Watch the blacks in the photo (or the darkest color if there are no blacks) to know when to stop dragging. Then click on the line at the very top-right, and move it to the left, this time watching the whites to know when to stop dragging.

Anyways, Wand tool:

As with the other background selections, it's better to use a lower tolerance with the wand and add to the selection than to try to get it all with one click. Clean up the selection with the Lasso if you need to. No need to do anything fancy like creating masks or using the Pen tool; the goal here is to do this as quickly, as simply and as easily as possible.

Now, to smooth things out, navigate to Select > Refine Edge (or Alt+Command/Control+R).

The dialog box that comes up has a lot of little boxes and menus and sliders, but the only thing we're going to worry about here is the Smooth slider.

Just drag it to the right, watching the photo to check the position of the edge. (if you can't see the selection preview well, click on that drop down menu, View, and switch to one of the other viewing modes - the red overlay is probably the easiest to use)

And we expand:

We can't contract like we did for the daytime sky with the blue backdrop, since that would expose white edges on the subject. I'm expanding by 2px here for a photo about 4000px wide, so adjust the amount you expand accordingly.

Then feather by an equal amount:

And then all that's left to do is fill the selection with a shade of blue (or black) in a new layer, just like you would do with the other colored backgrounds:

If you've still got some slight white edges around some blurry areas, like I have here around the battlements above the bucket, zoom in with a soft brush set to the color of the sky and just 'shave off' the edges. (if the entire photo has white edges around it, you didn't expand the selection enough. Undo back to the step where you expanded, and increase the amount of pixels you expand by)

Final step, if you're aiming for a nighttime sky: if you haven't done so already, you're going to need to go back to the original layer and use Curves to darken the photo and increase the blues. The reason you want to wait until now to do that is that you're selecting a white background. It's going to be easier to do that if you brighten that background, increasing the contrast between the subject and the background, than if you have to work with a dark background and a dark subject. Once the sky's in place, then you can drop the brightness of the subject to reflect the time of day you're looking for.

[Brickdoctor]

Assignment

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Take either two pictures, either one with a blue background and one with a black one or one picture with a white background. Using Photoshop, add the appropriate color sky to the background and the atmospheric effects created in Photoshop. (that is, blue sky, sun and clouds for daytime; black sky, moon, clouds and stars/starfield for nighttime)

Start a new topic (in the BF&CA subforum) entitled, "Student Enrollment: Basic Atmospheric Effects in Photoshop". In this topic, post your original image(s) and your finished Photoshopped images. Remember to resize them. (EB's guidelines ask for images no larger than 800px wide; do not post images smaller than 640px, otherwise it'll be hard to see the fine details of your photo) If you're having trouble or have questions, post in your topic and I'll see what I can do to help you.