Alright, some suggestions!
First off, never use the same star map for multiple images. It gives it a really fake look.
Another note on starfields: When your spraying out an area which you'll eventually copy-paste a couple times, its usually a good idea to use a larger area ... it looks to me like you used a 1x1 inch square for the copy-paste. Don't be afraid to use large areas, work that mouse!!
more information on building starfields in photoshop can be found (url="http://"http://www.roosteredge/com/~zombat")here(/url)
Secondly, You need to use difference clouds a lot more!! from what I can see, you only used one, or didnt use one at all. For (url="http://"http://www.roosteredge.com/~zombat/nebula/mysr.jpg")my nebulae(/url) I use at least 5 layers of different clouds, at different levels. (try rendering difference clouds, then rendering again). Another important part about difference clouds, that I have found out for myself, is altering the contrast of the difference cloud layers. This will stop the over-contrasted/(url="http://"http://www.roosteredge.com/~zombat/nebula/nebya.jpg")'sharp'(/url) nebula from occuring. (see upper center of image = the abrupt darkness, hole)
What I am happy to see, especially in nebula 5 that you did, is the fact that your usuing the image as a whole - many people make the mistake of making a nebula in the center of the image only. The key to making really realistic nebula is to making the nebula fade off the screen nicely.
Good Job!
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Some more Nebula-Making pointers -
- When spraying the base gray for the image, don't just make a big blotch, screw around with different patterns, look at (url="http://"http://antwrp.gsfc.nasa.gov/apod/")places like this(/url) for realistic nebula shapes, but DONT HESITATE to crop the nebula off the screen. Also, use the Gaussian Blur tool to smooth out sharp shapes perhaps caused by small brushes.
- Try inverting difference cloud layers - especially when you notice that the nebula seems a little too veiny (see: 'sharp' link for example) ... it can stop the veins from occuring, and sometimes add a nice cloudy look to it. (this usually occurs when you invert level 2 or 4 difference clouds. )
-Don't use too many levels of difference clouds - your nebula will start to become like marble stone.
- ALWAYS distort the Difference cloud layers usuing filters like; Polar Co-Ordinates, Pinch, Twirl, Vortex, Waves. Again, however, don't overdo - Use everything in moderation.
- Use the 'sponge' tool with a big brush to lightly desaturate (but not turn completely gray) areas like the fringes, or the centers (bright spots) of the nebula.
- Try copy-pasting star layers into a new document, rotating the new document 90° or something, and copy-pasting back in to prevent repetitave stars.
- Use the Burn tool or spraypaint can to darken particularly bright patches of stars. Also use the eraser to erase or dissolve stars 'within' the thick parts of the nebula.
- Lens flares won't always help an image, so unless your 3D program won't render them, dont use lens flares made in photoshop!!
