Author Topic: Color Calibration- When?  (Read 4047 times)

Offline JamieInCLT

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Color Calibration- When?
« on: 2012 March 07 09:01:31 »
People use different "recipes" for their workflow for PI, that is a given.  There are SO many tools that it is hard not to.

What would be great is to see what steps some people take, and when.

To me the early steps seem pretty straightforward, from a newbie standpoint, assuming that you have your masters set up (which I don't yet)-
  • Image Grading/rejetion
  • Image Calibration (if you have masters)
  • Image Registration (What I have been doing here is registering all images of a given target against the same, regardless of iso/exposure)
  • Image Integration (I try multiple things here, still learning)
    • Integrate them all at once, just to see what it looks like
    • For targets with blooming (m4 for example), integrate some smaller chunks of similar exposure/iso

(not mentioning STF, because to me that is a given every step of the way)

At this point, I would have one (or more) integrated images (note that I am using a DSLR, will be moving to a OSC soon- mono-cams would have multiples I would think)

Where do you normally go from here?  I would think that some other common steps would be
  • Dynamic Crop
  • Background Extraction (ABE or DBE, I seem to have better luck with ABE)
  • Color Calibration
  • Histogram Transform
  • Noise Reduction (ADCNR?  Something Else?)
  • SCNR
  • Sharpen/Unsharpen
  • Tweak Curves

Where in the above would the HDR Composition come in?  Should the background be extracted before combining, or after (does it even matter)?

Are there any steps that should be moved before or after the Histogram Transform?

I tried going through the gallery, but not many include their processing steps...

Thanks for reading,

-jamie

Offline Alejandro Tombolini

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Re: Color Calibration- When?
« Reply #1 on: 2012 March 07 09:35:45 »

I tried going through the gallery, but not many include their processing steps...


Hi Jaime, in the montly contest http://pixinsight.com/forum/index.php?board=17.0 there are images where the steps are well detailed

Saludos. Alejandro.

Offline JamieInCLT

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Re: Color Calibration- When?
« Reply #2 on: 2012 March 07 09:48:16 »
I hadn't looked there- thank you!

(wow those are nice :)


Offline Josh Lake

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Re: Color Calibration- When?
« Reply #3 on: 2012 March 07 10:01:27 »
Good question, one that I shared until a few months ago. Vicent Peris' processing of NGC 1808 on Youtube (two parts) was the touchstone for me to get my processing workflow figured out. He not only shows the steps, he explains the logic behind them, including the two-part color calibration process.

http://www.youtube.com/user/PixInsight#p/a/u/1/zqhLKIjGMXA

Also, with noise reduction, take a look at Harry's videos on doing Atrous Wavelet noise reduction while the image is still linear. This, too, was a big leap forward for me. If you follow Vicent's workflow, you might just do noise reduction on the Luminance frame and save any RGB noise reduction for the LRGB combination step (with just L selected).

Harry also covered my new favorite tool for helping to finish an image: Local Histogram Equalization. I can't believe I used to process without it!

http://www.harrysastroshed.com/at%20noise.html

http://www.harrysastroshed.com/LHE.html

Offline JamieInCLT

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Re: Color Calibration- When?
« Reply #4 on: 2012 March 07 13:00:00 »
My biggest problem with the color calibration is choosing the right thresholds- I need more work.  An image of m42 that takes up most of the field probably isn't a good choice for this :)