Artwork Help for Making Night Levels

Lighting effect is a good idea. It completely depends on your graphics style for the game, but a lot of times night-time graphics are only slightly darker, but very much more blue and purple and grey. This way your sprites can still be fairly bright but they look like they're in low-light.

 

As micah said, colors tend to shift to blue in darkness. However, changing a daylight photo or image to night is not an easy task. Light sources are completely different, shadows are cast differently.

A skilled artist would simply stylize the entire set of graphics, so that the effects would appear to be on purpose, rather than a gimped up half-assed attempt.

If you post an image, it would be easier to tell you what needs to be done.

 

It looks like you have everything under control. This isn't a photograph and you are working with a topographical viewpoint, so this makes the task much easier.

I think your color is suitable for night- I had no trouble seeing it as a night view. It doesn't look out of place and it doesn't look wrong (this is what I meant by stylized).

In some cases you can turn down the contrast and drop the saturation, then shift to blue using an overlay. But I don't think that is necessary for your art. The details look nice in the night view.

 

I like the initial dark effect you've done in the image above, but it's likely to be difficult to see on the iPhone screen at certain angles.

I've studied lighting for film and cinematographers can't actually shoot it in darkness or else nothing would show up on the camera. As mentioned by micah and Flickitty, they'll use blue light. If you find the correct bluish hue you might be surprised how bright you can make the scene while keeping it looking dark.

Taken from Halo Wars, I think this is a good example of night vs day:




Another thing you can do is use a few highly accentuated, high contrast light sources:



In your example image, I notice the runway lights. What you should do is make a lit area around each of those dots of light and casting strong shadows on the surrounding rocks.

 

try to make glow light something like this (it is quick variant)



may be try to make lights blinking

 

Blinking lights would be a cool effect. Especially if you can make them blink in a row, like a real runway in a flight sim. You even have the potential to go a bit further and add blinking lights to the planes too!

But when I said have the lights glow, I kinda meant like this:

 

My suggestion is to divide your background sprite into layers--try separating the mountain range from the ground so you can adjust the brightness and contrast for each sprite separately. At night, try putting some more "white" or "highlight" on the mountain tips and more shadows below each mountain. Also, a transparent top-view moving fog (or smoke) across the screen would be great for a night scene.

 

Maybe you can add some lights to the buildings so that they light up the planes on the ground. They can cast long shadows like in the Halo night pic above.

 

The glow on these looks good, but I think it would look better if you could see the point source more strongly in the center.

We will definitely have the lights blinking/strobing in a pattern to show the landing direction.

 

This would go in a completely different direction than what you're doing now, but since your game is sorta military-themed, you can give everything a green tint and completely replace the heads up display to make things appear like you're looking at them through night-vision goggles, maybe adding a cross-hair in the center or something. If you do it well it could look pretty cool. But the direction you're going in now is looking great too.