Postprocessing Images

A guide on how to postprocess images to get the most out of Terragen

Antialiasing

When you render an image in Terragen, there is almost always a sharp divide between land and sky (fig.1). The way to overcome this is to render the image double size and then resample the image to a lower size - preferably half size. This smoothes out the sharp edges, making the images look better. Most better paint programs (Photoshop, Paint Shop Pro, etc.) offer this feature.

Most of my images are originally rendered at 1500*1000 and resampled to 750*500 before putting them on the web. Bear in mind that at present, Terragen does not allow you to render images greater than 1000 pixels in height.


not resampled

using resampling

Brightness/Contrast/Histogram changes

Changing the colour balance is generally not a good idea with Terragen images, as Terragen tries to emulate real-world lighting already, and colour detail can be lost. It is far better to experiment with Exposure and Lighting settings instead. However, some nice effects can be gained by using gamma correction with values between 0.5 and 1.

Lens Flare

This will be an integral part of Terragen in the future. For now, you have to add lens flare manually using programs such as Photoshop. The key here is to make it subtle! Equally important is to choose the flare's origin point accurately. Usually, in Photoshop I will use between 50% and 75% brightness, or I will fade in a 100% bright flare.

Unsharpening

"Unsharpening" is a sharpening process that applies itself more to higher-contrast areas - which makes it perfect for bringing out details in craggy landscapes. I find it best to use a softening filter first, and then apply the unsharpening with a radius of around 1.5 pixels. I generally do this before antialiasing the picture.
no unsharpening

with unsharpening

And Finally...

The best way to approach any post-processing of Terragen images is - realism. Always try to keep the realism in your pictures and you should get good results.



render controls

landscape

water

clouds

atmosphere

lighting

image
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©May, 1999 John McLusky