Advanced techniques in MaxIm DL include Digital Development Processing and Deconvolution. These are powerful algorithms for enhancing deep-sky images.

Digital Development Processing

Digital Development Processing, or DDP, can be used to compress the tonal range of an image. If you have an object with both bright and dim detail, DDP will help bring both out. Go to Filter > Digital Development to open the DDP window. Set the Filter Type to None. This will avoid applying any sharpening, which is best done elsewhere.

Next, check Auto for Background under DDP Parameters at the bottom of the window. This will set the background level, but it is always too agressive. After checking the box, uncheck it to see what value was chosen.

Decrease the Background value by about 200 counts. For example, here the background level was 2248, so it was reduced manually to 2000.

For objects with a relatively bright region, such as the Andromeda Galaxy, shown below, you can simply check the Auto box for Mid-Level. See below for other possible settings.

Above is the Andromeda Galaxy, before Digital Development Processing. If we tried to stretch the image to show the faint spiral arms, the bright core would end up overexposed. By using DDP, the faint detail can be displayed along with the bright regions, as seen below.

Often faint nebulosity gets lost among bright stars in the Milky Way. DDP can reduce the brightness of the stars while enhancing the nebulosity, making it stand out more. In this case, a more aggressive setting can be used. Again, check and uncheck Auto for Background and reduce the level about 200 counts. In the case of the North America Nebula image below, the background level was only about 200, so it was manually set to 0. Instead of using Auto for Mid-Level, which would have been a value of 676, a much more aggressive stretch is applied by chosing a number closer to the background (200).

Below is the North America Nebula before stretching.

Below is the North America Nebula after DDP.

Next, Deconvolution Processing...

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