Advanced Evolved Stretching: Handling Regions of Very Different Brightness Within an Image

Evolved stretching is a quick, easy method to make a flat histogram transformation that is ideal for image development. The advanced method covers how to handle areas of very different brightness within the same image.
Foundational Material: Perfect Histograms in 60 Seconds -- Evolved • Perfect Histograms In ...
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[@thefailedastronomer7407]

Cliff my head is spinning. I'm going to have to watch this video a dozen more times in order to wrap my mind around everything you just said.😊

[@SKYST0RY]

I hope I didn't over complicate it. Essentially, just stretch to preserve detail in the brightest region of each region of an object, save each stretch separately, and then composite the stretches together, using alpha masking to remove blown out areas.

[@SamStars8811]

I'm feeling the same. I find activating the subtitles helps so I can pause the video when I need to.

[@SKYST0RY]

@@SamStars8811 With the more advanced topics, it's best to take notes. I think of this like learning to play an instrument. The theory and application are counter intuitive at first, but keep at it and one day you're doing it without even thinking about it.

[@Seafox0011]

Excellent. Am reminded of the Ansel Adams zoning system for photographic development. Bring the art to the technical. Thanks.

[@fotografiabymiguel]

Extremely insightful, I ordered Affinity Photo and will try this technique. Appreciate you taking the time to explain in such detail.

[@SKYST0RY]

I think it will like it. All the functionality of PhotoShop where it counts. AP still needs a proper histogram stretching tool and a better stacking tool. If it had something for sub,frame selection and a star alignment tool, PI would be almost redundant.

[@anthonygondola3086]

This is great stuff, I have learned so much from your previous videos in terms of improving my work using Affinity. One request though. These processes can become extremely complex and everyone's source images and needs are different. It would be great if you could see your way to showing the basic techniques you use in Affinity Photo one by one. That would give us a box of very general tools that could be applied to anyone's particular work flow.

[@SKYST0RY]

You may find this playlist helpful. It walks you through an entire layer-based editing process and goes into much of the foundational material used here. kzbin.info/aero/PL5QNoAcKJBRP7G0psAfSFUqXvglKWidAs&si=XZaxRJaur8Tzff1i

[@anthonygondola3086]

@@SKYST0RY Great, I will work through that...

[@thomaspierson7297]

wow verry cool i try that on my next astrophotos but i think i need 2 weeks for apply all your move on this program ^^ next time i need rewatch your video with X0.5 speed ^^ thx you

[@SKYST0RY]

Try practicing with the foundational video: Perfect Histograms In 60 Seconds--Evolved. It will walk you smoothly through the basic technique.

[@juancarlosvillar1557]

Impressive, my current goal is to improve the colours and the sharpening of my images, and your videos are a masterclass. Siril works well but managing the colours is not its best, and I am still learning Affinity. Will change to PI soon and your videos will surely. help. One question, in your final image, how do you create the effect of stars moving outside? It's cool

[@SKYST0RY]

The moving stars are actually very simple. I record a starfield from the 3D planetarium: Space Engine. It is then composited over the image via screen compositing. Before investing in PI, you may want to watch Thursday's video. I use it, but only for a few things.

[@juancarlosvillar1557]

@@SKYST0RY Thanks for the info. I will try your videos using only Siril/Affinity. Clear sky

[@SKYST0RY]

@@juancarlosvillar1557 PixInsight has some valuable tools, but I never use it for developing. It's mainly that it's clunky. Capable but archaic.

[@kevinivey8422]

Aside from having to watch this multiple times to follow along with all the excellent information, and I don’t mind doing it. I’m very appreciative of the information. However, I would love to see this technique implemented in Photoshop as well. I know that Photoshop can do the same thing, but due to the differences between the two programs, it’s all that much more difficult to follow along.

[@SKYST0RY]

Adobe is currently under lawsuit by the US government for unfair business practices and who knows what of the company will remain when the legal dust settles. They've already lost countless subscribers in the last few months due to excessive billing and practice of trapping people in subscription plans (which is what led to the lawsuit). I quit using Adobe when they began their monthly payment plan 14 years ago and soon discovered Affinity Photo. It is as capable as Photoshop for a one time purchase price of $100 and has an easy learning curve if you're already used to PhotoShop or Gimp. Give it a try. They give you a free six month trial period, which just can't be beat.

[@SKYST0RY]

Sorry, I don't mean that to sound rude. PS is very capable software. Adobe is the problem.

[@Seafox0011]

@@SKYST0RY Am wondering though if PS has frequency separation - I don't recall seeing it, even by another name ...

[@SKYST0RY]

@@Seafox0011 Sorry, I have no idea. I would imagine so, since PS is so similar to Affinity in function.

[@kevinivey8422]

@@SKYST0RY they have high pass filter. I have used this in a recent photo that I did by doing a radial blur first and then a high pass filter after that. I learned it from nebula photos Nico Carver when he was editing the solar eclipse.

[@christianvulpescu1398]

Very interesting. Thank you for this informative Tutorial. I am only experienced with PI. But there is a script there, which is called "Image Blend" - I think from " cosmic photons" - which is layer based. Would that method work there too?

[@SKYST0RY]

I've looked at the Image Blend script awhile back. As I understand it, it only blends two images at a time, whereas in a layer-based photo editor I can blend unlimited images, and even tools, at once. The Image Blend script has very limited options for tool application and masking. Because it isn't layer-based, it is not possible to apply any tool to discreetly selected points of the editing process, greatly limiting the possibilities. So, I think that while you could do some of this in the Image Blend script, I am not sure how far you could take it. In the end, working with PixInsight, you would probably have to go about many steps pretty differently, and I am unsure if you could get the same quality of results. TBH, due to its limitations, I quit editing images in PI ages ago.

[@christianvulpescu1398]

@@SKYST0RY Makes sense. Thank you. 🙏😃👍

[@JonnyBravo0311]

You do a good job of getting the detail in the cores; however your color balance is completely wrong. You took out way too much red and left it heavily blue/green tinted.

[@SKYST0RY]

Is your monitor Dep3 or Adobe RGB color space compatible? If not, you will only see the much more limited sRGB color space and colors will show up brighter, darker or possibly with banding as compared to the original image. And is your monitor color calibrated? Few are out of the box, unless you are using a monitor specifically made for developing and viewing images and videos. My images are processed for the Dep3 color space on a calibrated monitor, however, they should show up fine on Adobe RGB capable monitors and will generally show up ok on a balanced sRGB monitor as long as it's not far off calibration in either color, temperature or hue. With that said, the image doesn't contain much color information. In fact, the image is only 5.45 hours of integration time, so it doesn't contain much information at all, and only 20% of the subs were in RGB. The image was shot as a test to compare the resolving power of an SCT against a refractor. But pulling detail is the focus of this video. Color theory, balancing and calibration are very different topics for other videos.

[@MrZilpah]

I would kindly suggest to use some sort of color calibration, too. SPCC on the linear(!) image, in PI for example, then continue with the rest of your workflow. The background has a blue tint, too. Yes, I'm using a colorist grade monitor (team Eizo here!) but initially saw this on iPhone 15 pro max and it stood out right away. Just giving you feedback, do with it what you like :-)

[@SKYST0RY]

@@MrZilpah That's good to know. Is your monitor using ProPhoto RGB, Dep P3 or Adobe RGB? I have put two renditions of the image on Astrobin. If you could take a look and let me know which appears more color balanced, it would help because I am not seeing the cast on my iPad, iPhone or 2K gaming monitor, and it's only very slight on the 4K editing monitor calibrated for Dep P3. www.astrobin.com/bvs7mz/H/