Changing the grayscale range within a height map

[Redrobes]

Thats not a problem. The easiest is with a graph tool but I am familiar with PSP not Gimp or PS but I would imagine they have one too. This graph tool is one where you can draw a curve (set points and it interpolates the line) for the input and it will scale the luminance to the output.

By setting the curve such that its a two point straight line where 0 goes to 50 and 255 goes to 155 it will directly convert that map to your requirements.

If you dont have one of those then its easier to get it by first getting the range correct then by setting the brightness. So first of all you would drop the contrast from (255 - 0) = 255 to (155 - 50) = 105. Thats a 105/255 drop which is 41% of original. That in most application terms is a -59% contrast adjust. Then you would have an image which is of that new range but it offsets it by default around the mid grey mark. So it ought to be 128 +/- 52. So you need to drop it by another 26 to get it to 50 to 155.

Like I said - the graph tool does it all for you tho. No messin'.

You might want to think about using 16bit heights to prevent the banding that will occur. And b) you can try my totally free 3D visualizer for height map data. Save the image as Height.bmp (or PNG) and then run the app in the same dir as the image.