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DSLR-LLRGB Style Processing and Walkthrough Video
 
 
M45 using DSLR-LLRGB Style Processing
M45 using DSLR-LLRGB Style Processing

DSLR-LLRGB Style Processing Workflow
  While processing my DSLR images, I was continually disappointed with the result whenever I tried to either bring out fine detail, push up the brightness of faint areas, or tried to fully saturate my images. All of these processes tended to increase the noise, especially chromatic noise within the image. As a result, I developed a new workflow which is giving me much more satisfying results with my DSLR images.

Basically, my workflow involves an adaptation of CCD style LRGB processing to DSLR images. It also utilizes Robert Gendler's technique of multi-luminance layer processing (Robert calls this LLRGB). As such, I can best describe my workflow as DSLR LLRGB-style processing.

In the video below, I demonstrate a complete walkthrough of my processing of an exceptional wide field image of M45 that was imaged by Neil Heacock. Neil generously provided the data for this image as a processing challenge for his DSLR Astro Image Processing Yahoo group (if you're interested in a great way to learn more about image processing, I HIGHLY recommend joining this group). While I apologize for the video being so long, it is intended to be a COMPLETE walkthrough of almost all of my typical workflow.

In order to make it easier for you to view the video, I have also broken it down into smaller, bite size chunks. I intended each of these clips to be a lesson on its own. So, if you're not particularly interested in how I stretch my data, but you're curious about my technique for doing a Screen Mask Invert, you can simply go to the Screen Mask Invert link and watch that clip by itself.

At the bottom of this page, I have also posted my basic workflow in case you're interested in using some or all of my DSLR-LLRGB Style Processing Workflow. I'm not sure I would recommend this technique for astrophotographers who are just beginning to learn the ins and outs of processing their images, as the workflow is a bit more complicated than standard RGB processing. For those with less experience, I think Neil's 15 Steps for Great Astrophotos is an excellent workflow. In fact, it is from where my workflow originated.

Thank you for stopping by my website,and I hope that some of this info is helpful to you.



DSLR-LLRGB Full Walkthrough Video
  Full Walkthrough Video of DSLR-LLRGB Style Processing of Neil Heacock's Widefield M45 image (2:07:03)



To Download the MP4 Video file directly to your computer, right click on the link below and Save the file to your computer:

Direct Download Link to Full Walkthrough Video (MP4)




IMPORTANT CORRECTIONS:

Please take note of the following errors and clarifications in the video:

1) Midway through the video (at 00:51:00), I have a lengthy section to demonstrate how I implement Jerry Lodriguss' Screen Mask Invert method (a superb method for enhancing faint nebulosity in an image). In this particular image, I leave the Screen Mask Invert group at 100% opacity because, uncommonly, it works well for this M45 astrophoto. However, I should have noted that I almost NEVER apply Screen Mask Inverts at 100% opacity as it usually will make an image look very bad (it creates a very oversoftened artifact). Most commonly, I set the Group layer opacity on my my Screen Mask Inverts between about 25% and 35%, and rarely more than 50%. You'll need to decide with your image what the best opacity is, but keep in mind that if you're over 50%, chances are pretty good that you're doing more damage than good. Also, it often will work better to apply two low opacity Screen Mask Inverts (say, 25% each), than a single higher opacity Screen Mask Invert (i.e., one SMI at 50%).

2) Towards the end of the video (at approximately 1:47:11), I describe an excellent saturation method of duplicating layers, setting the top layer to Luminosity mode, and the middle layer to Soft Light mode. My understanding had been that this wss a method developed by Adam Block. This assumption is not correct - the method was actually developed by Jay GaBany. My sincere apologies to Mr. GaBany as well as Mr. Block for having disseminated this erroneous attribution.

3) Later in the video, I describe using Lab Color to increase saturation in the color channels. I incorrectly say (at approximately 1:55:22) that the "a" channel affects the red/cyan colors. I should have stated that the "a" channel affects the magenta/green colors.



Video Clips Demonstrating DSLR-LLRGB Workflow




  Introduction (1:13)

  Workflow Overview, Initial non-aggressive stretching using Images Plus' Digital Development (2:40)

  Initial Crop, Initial Levels, Gradient Xterminator (GradX was not used on this image) (6:17)

  Convert to Greyscale, Begin Processing Luminosity Image,
Deconvolution, Sharpening using Images Plus' Multiresolution Sharpening (10:42)

  Selecting Stars, Combining the Sharpened Image (8:10)

  Noise Reduction - Carboni Deep Space NR and Images Plus' Standard Smoothing and Noise Reduction (7:38)

  Stretching the Image (12:41)

  Fixing Flaws (1:57)

  Screen Mask Invert - very useful for brightening and smoothing faint nebulosity (17:07) Please see the IMPORTANT CORRECTIONS for information about lowering opacities on Screen Mask Invert layers.

  High Pass Filter - increases local contrast and has a sharpening effect (8:07)

  Second Screen Mask Invert - slight differences in levels adjustment method from first SMI (7:00)

  Star Shrinking using minimum filter (5:11)

  Final Stretching and Contrast Curves on Luminosity image(8:57)

  RGB-Luminosity Combining - Purpose of RGB and Luminosity Layers, Run HLVG, Reduce and Blur Noise in RGB Layer (8:59)

  Jay GaBany Method for increasing Saturation without increasing noise (4:45)
Note: I had previously described this as the Adam Block method instead of the Jay GaBany method for increasing saturation. Please see the IMPORTANT CORRECTIONS section for a more thorough explanation.

  Blurring RGB image and then increase saturation with Lab Color (8:04)
Please see the IMPORTANT CORRECTIONS section for information about using the "a" channel.

  Other Color increasing/adjusting methods, applying final luminosity (3:43)

  Final Color Curves and align Color Channel Peaks (4:54)

   
DSLR-LLRGB Step by Step Workflow
  Scott's DSLR-LLRGB Style Processing Workflow (as of 6/1/12)

INITIAL PROCESSING OF RGB IMAGE

1) Perform Initial Stretching - not an aggressive stretch. I use Images Plus' Digital Development, but any stretching method or digital development will work fine.

2) With multiple stacks of images (typically from multiple nights), align all images in Registar.

3) Combine Registar aligned images in Photoshop (set opacity to match each layer's contribution to the total).

4) Initial Crop to remove ragged edges.

5) Initial Levels (set white, grey, black points).

6) Gradient Xterminate (Med/Low, Fine/Med). Usually use method described on Russell Croman's Tutorial page.



PROCESSING OF LUMINOSITY IMAGE

7) Convert RGB image to Greyscale.

8) Perform Deconvolution, Sharpening. I usually use Images Plus' Advanced Lucy-Richardson Deconvolution to restore focus.

9) In Photoshop, combine ALR versions, mask to areas that need sharpening only, i.e., detailed portions of galaxies.

10) Peform additional sharpening, as needed. I usually use Images Plus to perform multiresolution sharpening.

11) In Photoshop, combine multires sharpened version, mask as needed (sharpening usually applies to highlight areas and some slight sharpening of stars).

12) Perform Noise Reduction routines. I typically use Carboni Deep Space Noise Reduction. Back off the opacity as needed. Then, I take this version and bring it into Image Plus and uses IP's Standard Smoothing and Noise Reduction. Next, I apply the IP Smoothed and NR version as a layer and back off the opacity as needed.

13) Perform aggressive stretching to bring up faint galaxy halos and nebulosity, Increase brightness and contrast in DSO as needed (apply curves using DSO and/or faint fuzzy mask).

14) Fix Flaws - use spot healing brush tool to fix up hot pixels, asteroid trails, etc.

15) Screen Mask Invert, Levels (reset black point) as needed. Perform multiple times, if needed. Be sure to lower opacity on group layers - typically to 25% to 35% and rarely above 50%.

16) High Pass Filter as needed, possibly with different radii. Usually mask to DSO areas that need contrast enhancement.

17) Perform Star shrinking routines in Photoshop.

18) Smart Sharpen, if needed.

19) Final Levels and Curves to luminosity layer.

END OF PROCESSING OF LUMINOSITY IMAGE



FINAL COMBINING OF RGB AND LUMINOSITY IMAGES

20) Open image from last step of initial RGB processing.

21) Curves to roughly match Luminosity.

22) Run HLVG (Hasta La Vista Green).

23) Carboni's Space NR.

24) Carboni's Less Crunchy, More Fuzzy.

25) Several Runs of Saturation increase using Block Method until the image is slightly oversaturated.

26) Apply Luminosity Layer. Set opacity until saturation in image is a little low.

27) Blur image each time Luminosity layer is applied. Use a combination of Carboni's Less Crunchy, More Fuzzy followed by a gaussian blur of 2 pixels.

28) Continue increasing saturation and adjusting color by a combination of Block Method, Selective Color adjustments, Lab Color, and Vibrance (not necessarily all of these methods for any given image). Increase saturation each time until image is slightly oversaturated.

29) Apply Luminosity layer again. Set opacity higher once again, until saturation in image is a little low. After each application of Luminosity, follow by Less Crunchy, More Fuzzy and then a gaussian blur. Keep repeating until Luminosity layer can be applied at 100% with good saturation.

30) Final minor curves adjustments, if needed.

31) Final Levels adjustment to line up color channel peaks (usually adjusting gamma to line up channel peaks).