DDP - what is it?

[dsnay]

Hi all,

Someone on the autostarsuite.net forums played with my M13 image using DDP and made it sparkle more. Can anyone tell me what it is and some options for how to acquire it? If you have other methods to accomplish the same thing without buying more software, I'm all ears. The wallet is pretty light right now.

Thanks,
Dave

[sc02492]

Dave, DDP stands for "digital development processing".  It's a fancy way of applying a vigorous curves stretch to an image, in a manner that will bring out the low end of the histogram without blowing out the highlights.   DDP is a feature of many image processing programs like Maxim or ImagesPlus, and I find it useful for that initial curves stretch of a raw CCD image.  However, you really don't need DDP to get nice images from a CCD chip- you can accomplish the same thing using curves in Photoshop.

Steve

[dsnay]

Thanks Steve.

When you say initial stretch of the curves are talking about raising the high values and lowering the lows? sort of making and "S" out of the curve graph in each of the layers?

thanks,
Dave

[sc02492]

Dave, not exactly.  An "S" shape to the curves would increase contrast.  What you want to do with a raw, unprocessed CCD image is to stretch everything, but especially the lows and the midrange.  You need to boost these areas in order to mimic the processing that the human eye/brain does automatically.  Here's an example of a typical curves stretch:

http://www.starrywonders.com/cannistratutorial2.jpg

This is from my old tutorial:
http://www.starrywonders.com/tutorialpage1.html

Steve

[dsnay]

Thanks Steve,

I remember that tutorial. I'll have to go give it another review now that I'm actually capturing some useful data.

Dave