PART II: The Space Scene
Step 11: Nebula

In this step we will give our space scene a little color. No, seriously, just a little color. Keep in mind as you work through this step that your nebula should not be overly bold or bright as this will tend to make it stand out and take away from the other items in your scene. We want to give our scene a nice color that sits in the background with our star field and adds some interesting variety and not some bold color that is the image's focal point.

1. Open your Space file in Photoshop
2. Press D on the keyboard (remember what this does?)
3. Insert a new layer and name it Nebula1 - make sure this new layer is NOT in the Star Field layer group but is above it in the layer stack
4. Select the Nebula layer and fill it with black...
   
5. Change the blending mode of the Nebula layer to Linear Dodge (Add) - notice that you can now see your stars through it
6. Select the Lasso Tool...
   
   The Lasso Tool allows us to make selections of any shape we like
7. On the Lasso Tool Option Bar set the Feather to 75px...
   
   This will give our nebula a nice, soft edge
8. Click and drag to create a region to place your first nebula - it can be anywhere you want and any shape you want, but remember that if you place it where you placed your bright stars they will become difficult to see...
   

Notice that when you release the mouse after drawing your selection area that the selection will change, sometimes dramatically, to be more rounded than your original area...

This happens because the feather is set so high that the selection will have very spread out edges. This is what we want at this point.

9. Click the Switch Foreground and Background Colors icon to set white as your Foreground color and black as your background color
10. Change the Set foreground color to the color you want your nebula to be - it should be a dark shade and NOT bright or your nebula clouds will look unnatural...
    
    Notice how the bright pink on the left looks unnatural and could even be some space blob that is about to eat our solar system, where the darker color on the right gives us the slight color we want - we don't want too much color at this point as we will be adding in more clouds (including different colored clouds) in the coming directions
11. Click Filter then point at Render and click Clouds...
    
12. You should now have something similar to the image below (no, yours will not look just like mine)...
    
13. If you think the nebula is too bright or you don't like the shape you can undo and try again, or you can simply use the Eraser Tool to remove some of the clouds until you get something you do like
14. Repeat the above procedure several more times until you have a nicely built nebula; keep the following in mind as you build your nebula:
    1. Place each new shape and color on its own layer
    2. Name each new layer you create in numeric sequence: Nebula1, Nebula2, Nebula3, etc.
    3. Create a nebula with AT LEAST 2 different colors - you can certainly have more, but don't go crazy (there are very few real nebulae with more than a handful of different colors)
    4. Feel free to use a variety of colors as you create your nebula, but make your color shifts small (for example from blue to turquoise or from purple to lavender) or the nebula will look unnatural
    5. Do not use black or white
    6. Do not try to fill the entire image with color
    7. Be sure to set the blending mode of each nebula layer to Linear Dodge (Add)
    8. Try not to make sections of the nebula too dark - you should always be able to see the stars through your clouds
    9. Try to make some areas of color larger and some areas smaller - this will add to the realism
    10. When trying to make small areas of color, you may get the following message: Warning: No pixels are more than 50% selected. The selection edges will not be visible. If you do, don't panic, Photoshop is simply telling you that the selection you have made is so small that it cannot be displayed using the current feather setting (this is not an error, just Photoshop letting you know that it will not show you the marching ants that indicate a selected region) - the selection is still there, so after clicking OK on the message, go ahead and render the clouds and you will see that something is indeed applied
15. Select all of the nebula layers...
    
    (You may have more or less nebula layers - this is OK) and click on the Create a new group icon
16. Rename the layer group you just made Nebula...
    
17. Take a look at your nebula and make sure it is not too bright - look at this...
    
    Notice that the nebula is so bright that you can not see the stars through it - your nebula should be a splash of color that sits in the background of your image to add interest and variety to your space scene and not a bold area of color that screams 'look at me!' - if your nebula is too bright, you can quickly and easily soften it up by decreasing the opacity (the depth of color) of the Nebula group to get it down to something more realistic. Simply make sure your Nebula layer group is selected in your Layers panel (it should be highlighted in gray as in the image below) then click the Opacity drop down arrow (1 in the image below) and grab the Opacity slider (2 in the image below) and drag it to the left (3 in the image below)...
    
    Until your nebula is a nice soft color and you can see your stars through it...
    
    Keep in mind that the images in this step are screenshots and thus are not as detailed and pretty as your nebula should be

18. Lock the Nebula layer group...
    

Keep in mind that we will be adding planets (and a bunch of other stuff), so much of our nebula will be covered up. If there is an area (or areas) that you do not like, don't worry about it right now. You can stick a planet over the problem area so that it won't show in the final image.

19. Save your Space file