I will do even better than that Lewis. Sorry I missed your post.
Here is an image of 30x4 min of each of RGB. X1.5 native pixel size. 16MB
http://d1355990.i49.quadrahosting.co...070_DBE1_L.jpg
Here is the same data at native res, only had DBE applied with Pixinsight to get rid of gradients. This happens while the data is still linear and unstretched!
60MB
http://d1355990.i49.quadrahosting.co...70_RGB_DBE.zip
You can see the gradients in the second small image below.
Bert