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Eclipse HDR stack processing tips for Affinity Photo

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#1 joofcorn

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Posted 17 April 2024 - 05:55 PM

Since tips and tutorials are everywhere for using photoshop and the radial blur method of bringing out more detail in the corona, I thought I'd quick write down how I was able to do something similar using Affinity Photo since it's not as intuitive to figure out.  Quick note, this can be done in V1 or the newer V2 versions of affinity photo, however V2 absolutely handled stacking and calculation better for many images.  I had V1 crash on me and corrupt a save file when trying to stack and process a dozen or more frames.

 

1)  Similar to photoshop, get all your frames into a layer (File -> New Stack), do not auto align.  It may take a while depending on how many frames, but eventually will load as Live Stack Group.  You can then align and center your frames however you prefer.  Default blend function on the stack though is median I think, so be sure to click on the symbol by the layer title, and select mean (median also can product ok results if you prefer the look it provides)

live group

 

2) after you have everything aligned and the stack looks good, right click on the layer panel and select "Merge Visible".  This is I think the equivalent of a stamp layer in photoshop, just making a pixel layer of what's on screen.  Make 2 copies of this layer, and turn off the stack visibility (helps with processing times)

 

3) On the top of the 2 stack layers you have, go to Layer -> New Live Layer Filter -> Blur -> Radial Blur.  This step is also still similar to photoshop.  Start by selecting maybe 20-30 deg. 

radial blur

 

4) Now with that layer still selected, go to Filters -> Apply Image.  Once the dialog is open, click your bottom layer (I've named my examples base and radial to help) then click the "Use Current Layer As Source" button.  Next click back onto the top (radial) layer.  Check the "Equations" box, select "Greyscale" color space, and change the "Blend Mode" to either Difference or Subtrack.  Then use the following 2 equations.  Click Apply.
    - DI = SI - DA + 1

    - DA = SA - DA + .5

apply image

 

5) At this point you can click on the radial live filter and adjust the spin amount to your preference and see how the structures being accented might change.  I ended up stacking some at 20 and 80.

 

6) Use merge visible or something similar to now make a copy of this grey filter.  Disable the live adjustment layer, and change your blend mode to one of the lighting options.  I preferred the look with "Linear Light".  Below is an example of before and after I applied these filters

layers Off
layers On
 

7) This method did give me a blueish color cast on everything.  If you find that distracting, you can make a final "Merge Visible" layer, then go to Filters -> Astrophotography -> Remove Background.  You'll see the below dialog and a circle in the middle of the screen.  Drag that to one of the dark corners and select "Sample at Handle Position".  This will try to flatten to a black background.  You can then tweak some of the color settings to your liking, then click Apply.

remove background
 
You can obviously change parameters here, or do more, or maybe you don't like the look of this at all.  I just know I've seen a lot of people/threads/videos etc showing how to use Radial Blur, then grey calculations in Photoshop to do this effect, as well as some people trying to figure out something similar in Affinity Photo.  I hope this will help someone that uses affinity and trying to create a similar look as this took me a long time to figure out.

Edited by joofcorn, 17 April 2024 - 05:56 PM.

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#2 swsantos

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Posted 18 April 2024 - 12:51 PM

Thank you for this! Indeed there is a shortage of Affinity Photos tutorials on eclipse processing for those of us unwilling to bend the knee to Adobe's subscription only Photoshop. 

 

You have imported tiff files. Did you convert them from camera raw files for this purpose first?

 

Would you advise importing raw files at the outset if available?

 

How about importing JPEGs instead? (others here may be interested in the file importation differences as well)

 

I actually tried to use AP2 for this last night but couldn't figure out how to align the images. I imagine showing two at a time with one being the base is the way to go like Photoshop (I did so with Photoshop Elements), but I think there has to be a particular blend mode in play for that purpose? Could you help a noob (me and anyone else drawn to this thread's title) by expanding upon #2 above "after you have everything aligned and the stack looks good" regarding the alignment process, order, and relative opacities of the layers?

 

Thanks!


Edited by swsantos, 18 April 2024 - 12:52 PM.


#3 joofcorn

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Posted 18 April 2024 - 01:32 PM

I used Rawtherapee to do raw edits before exporting to uncompressed 32 bit TIFF in order to retain as much detail as possible.  I could have just done a straight TIFF export of the raws inside Rawtherapee as the images were good enough out of the box, but I chose to do some light editing before exporting.  You could use jpeg if it's what you have available (maybe someone couldn't or forgot to shoot in raw), but uncompressed tiff or dng file will keep the most data.  I did try just doing the raw files directly into the stack inside affinity, but affinity didn't seem to do as good of a job processing all the raws at once, and there was color banding artifacts happening.  You can see what this looked like in this screenshot. 

corona banding
 
Aligning images could be done a ton of ways, and people align on different things.  I've heard some people use the prominences to align while others use the moon shadow (ie keep sun position fixed, or moon position fixed).  I personally just do the moon shadow as it's a bit easier.  Using something like a prominence to keep the sun fixed instead of the moon might make for a better stack, but I haven't tried. 
 
If you're trying to use this radial blue method, the first step is going to be centering that first image and hide all the others for now.  This has to happen since that's the point used for the radial blur to center on, and it can't be changed.  I did this by going into View -> Guides and clicking the new guide button for vertical and horizontal.  This will automatically put each in the center.  I then added 2 more guides to box in the moon shadow.  How far away those need to be will depend on your field of view.  For my setup it was +/- 377px I think.  Then it was just a matter of centering that first image.  When using the move tool, arrow keys are you best friend since you can nudge one pixel at a time.  I wouldn't even both trying to use a mouse or trackpad for these alignment steps.
aligning with guides

 

To center the remaining images, I just continued to use this box to center everything one by one (keeping only 1 layer on at a time).  Another route to go would be to keep the bottom layer on, and turn other layers one 1 at a time.  You can then see when the "average" of the two layers happens, you can center each image to the first.  For longer exposures this is a little tricky as you can see below due to the outer portions of the moon shadow getting blown out, so the moon shadow of a long exposure looks a lot smaller than on a short exposure.
Not aligned
aligned

 


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#4 swsantos

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Posted 18 April 2024 - 11:01 PM

So far so good, I am at step 2 and have just Merge Visible so now in the right panel there's Pixel at the top and underneath is Live Stack Group collapsed and made not visible and I have saved the current image as a TIFF file so that at least I have a nice basic HDR file.

 

The next step is to make "2 copies of this layer". Does that mean I right click on Pixel and copy or duplicate (it appears duplicate is the choice as it creates another layer) and do I make one more so there are two total or is your instruction literal and do I make 2 additional copies? Do I rename one of the new Pixel layers to Base and the other Radial?

 

I went ahead and made two duplicate Pixel layers and named the top one radial and the bottom one base but when I followed the instructions I never got and layers named Spin. 

 

Could you expand on instruction 5 and 6 because after #4 because I am not seeing what's in your screenshots.

 

Here is that first version uncropped and unprocessed further, a stack of 8 TIFF files, saved to a cloudynights sized JPEG.

 

TSE HDR 8bit (Large).jpg

 

Thanks!

 

 


Edited by swsantos, 18 April 2024 - 11:36 PM.


#5 joofcorn

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Posted 19 April 2024 - 02:00 AM

All the layer names were just me naming to help organize what I'm doing.  As far as copying layers, after doing the first "Merge Visible" you should get 1 layer on top that just gets named "Pixel" by default.  Any layer can be renamed by just clicking on the layer name.  You can then just click on the layer to copy/paste (ctrl keys or right click both work).  At this point your layers would look like:

Pixel (I renamed this to radial)
Pixel (I renamed this to base)

Live Stack Group

 

Step 5 is really just saying that once you're able to get the grey looking image with corona details, you have the option to click on the radial filter in the layer panel to adjust the amount while seeing the results live.  If you're struggling with some of the steps, it might just be easiest to pick something like 20-30 and roll with that.

 

The spin layers in my screenshots would have been ones I created using "Merge Visible" at step 6.  This is similar to earlier and you would get a new Pixel layer that you can rename, and also could turn off the radial layer.  Blend modes can be changed by clicking the dropdown on the layer panel that is usually set to "Normal" by default.  Best options seem to be Overlay, Soft Light, Hard Light, or Linear Light.  So at this point you layer stack might look like:

Pixel (just created)

Radial (can turn off)

Base

Live Stack Group (can turn off)

 

You can then copy and paste that top pixel layer a couple times to increase the sharpening effect.  I do notice that it looks like your range of exposures is probably a little more narrow, so I'll be curious to see how much more detail you can pull out of the corona using something like this.  Before you do the radial filters, it might be worth trying to stretch the exposure a bit using Layers -> New Adjustment Layer -> exposure, or Brightness/Contrast.  How much you can push these to get more will just depend on how much dynamic range your camera was able to capture.



#6 swsantos

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Posted 19 April 2024 - 12:05 PM

  I do notice that it looks like your range of exposures is probably a little more narrow, so I'll be curious to see how much more detail you can pull out of the corona using something like this.  Before you do the radial filters, it might be worth trying to stretch the exposure a bit using Layers -> New Adjustment Layer -> exposure, or Brightness/Contrast.  How much you can push these to get more will just depend on how much dynamic range your camera was able to capture.

I do have 10 stops of pictures available but only used 8 of them for this version, choosing not to use the two longest exposures on purpose for fear I would not be able to align them because the area closest to the moon that I used your guides to align is so blown out there's nothing to accurately align on plus I wanted my first HDR to have a black moon reflective of the eclipse's natural appearance.

 

My plan was then to try restacking all 10 images that I have to widen the range of detail available and I am hoping to get some Earhshine out of that one. So on that HDR attempt I will push past where I left off on this one and try the radial blur enhancements.

 

Can I use my current 8 exposure stack which I saved in Affinity Photo after Merge Visible in step 2 and simply add the two additional exposures and align them or should I start with a new document from scratch with the 10 exposures? Can two more images be added such that they become part of the original stack as if I had done it that way from the beginning? Any advice on aligning a somewhat blown out inner corona without alignment landmarks to the stack?

 

Thanks!



#7 joofcorn

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Posted 19 April 2024 - 07:25 PM

If you imported them as TIFF or JPEG or something, you should be able to just add then drag the extra layers into the live stack later, yes.  If you imported as raw, its a little more complicated as you'll need to first import with the affinity "develop" module, then i think copy the layer into the stack. What i did to help aligning the more blown out moons was to add more guides.  What worked for me was going 20px closer to the center.  Even if it doesn't perfectly match the size of the shadow that isn't blown out, it will still be easier to center.  I will say that since the live stack since it averages the output of all the frames, if some of the frames are a bit off, its not a huge deal.  I've noticed a frame being 10 or more pixels off before and the results still can turn out great.  It just might not be as sharp if it is well centered.

more guides


#8 swsantos

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Posted 21 April 2024 - 12:17 AM

Trying the radial blur on step 4 after the equations, I cannot get that grey embossed looking appearance, all I get is a blurred eclipse with a blurred corona. The moon has a blurred black appearance and not all grey like your screenshot so I must be doing something wrong.

 

Radial blur.jpg


Edited by swsantos, 21 April 2024 - 08:45 AM.


#9 joofcorn

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Posted 21 April 2024 - 10:54 AM

Double check that you have your layers centered in the frame using guides.  If the layer off center, the radial blur will make the image look like that.  If your live stack has everything aligned to each other, you don't have to change all of those, you could just shift your base layer, then make a new layer from that for the radial filter.

layer Not centered

Edited by joofcorn, 21 April 2024 - 10:54 AM.


#10 jdj

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Posted 02 May 2024 - 07:47 PM

Thanks much for working through this process in Affinity Photo.  I followed the discussion thread and was able to get this to work as well.  In addition sharpening using radial blur in Affinity Photo, I applied an additional sharpening step using NAFE solar image processing software.  Here is my result and the steps I used to generate the image:

 

https://astrob.in/ktrqx2/F/



#11 jdj

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Posted 02 May 2024 - 07:48 PM

Here is the final image:
 
HDRNAFE


#12 WayneReed

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Posted 06 May 2024 - 06:40 PM

I really appreciate the helpful info on processing totality images.  I am new to Affinity Photo 2 and purchased it because my Photoshop Elements was missing some of what I need and a ZWO rep mentioned Affinity Photo.  I am having trouble with the process from the radial blur onwards.  I am attaching a view of my Base layer (mean blend of 6 images).  I clearly see rings where layers are saturated.  My Radial Blur layer still shows the moon and does not show coronal rays.  I used 20% rotation for this.  I can't figure out what I am doing wrong.  Any suggestions gratefully received.

 

Wayne

Attached Thumbnails

  • Screen Shot Base 05-06-24 at 07.18 PMa.jpg
  • Screen Shot Radial Blur 05-06-24 at 07.19 PMa.jpg


#13 jdj

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Posted 07 May 2024 - 05:05 PM

I really appreciate the helpful info on processing totality images.  I am new to Affinity Photo 2 and purchased it because my Photoshop Elements was missing some of what I need and a ZWO rep mentioned Affinity Photo.  I am having trouble with the process from the radial blur onwards.  I am attaching a view of my Base layer (mean blend of 6 images).  I clearly see rings where layers are saturated.  My Radial Blur layer still shows the moon and does not show coronal rays.  I used 20% rotation for this.  I can't figure out what I am doing wrong.  Any suggestions gratefully received.

 

Wayne

A couple notes from my processing experience:

(1) In the original post step (4) the equations were written up as:

  DI = SI - DA + 1

  DA = SA - DA + .5

However, if you look at the screengrab from the post they are actually: 

  DI = SI - DI + 1

  DA = SA - DA + .5

I used the second set of equations.

(2) When setting the radial blur filter angle, I had to select "preserve alpha" (as shown in the screengrab in the original post). I originally neglected to and was not successful.

(3) I am new to Affinity Photo 2 as well and it took me some trial and error to figure out the following step from the original post "Use merge visible or something similar to now make a copy of this grey filter.  Disable the live adjustment layer, and change your blend mode to one of the lighting options.  I preferred the look with "Linear Light".  Below is an example of before and after I applied these filters."  Here are my notes for this step: 

> Create grey radial filter: 

  - With ‘Base’ and ‘Radial’ layers visible, select the layer ‘Radial’, right click, select merge visible
A new layer is created, name it ‘RadialMerged’

> Create radial blurred base image:
  - With 'Base' and 'RadialMerged' Layers visible, others not
  - Select RadialMerged Layer, change blend mode to “LinearLight”
  - Right click on RadialMerged Layer and select Merge Visible
  - Creates new layer with radial blurred base image

(4) I see a lot more structure in a lighltly radially sharpened image that is then further sharpened using the NAFE solar image processing software.  I suspect this is due to the not so great quality of my data which was shot through high clouds.

 

Hope this is helpful...



#14 WayneReed

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Posted 08 May 2024 - 10:47 AM

Thank you JDJ for your detailed comment.  I still can't get there.  I am going to start by trying to get rid of the rings I have.  They are the outer edges of the over-saturated portions of the corona in each exposure. Perhaps I can reduce them with curves or other methods, then retry the spin blur, which currently gives concentric rings.

 

Wayne


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#15 WayneReed

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Posted 08 May 2024 - 05:10 PM

I found that the rings must be due to the cirrus clouds above the Dayton, OH area when I took my pictures.  My first hope was that I use 100 and 10 frames for the exposures and then stacked them in AutoStakkert prior to using the resultant images in Affinity.  Using single frames today made no improvement, so it must have been the over-saturated cloud effect that left the rings.  I have not figured a way to reduce the saturated pixels to soften the ring formation when mean-stacked.  If one knows how to do this I would love to know.

 

Wayne



#16 WayneReed

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Posted 09 May 2024 - 09:48 AM

I finally figured out a way to get rid of the rings in my mean-stack. I used curves adjustments on each image to reduce the saturated level from 255 to around 220, then putting the layer into the live stack. The rings are virtually gone now, leaving the corona. Next I will try the suggestions from joofcorn and jdl to bring out coronal details.
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#17 Lazac

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Posted 13 May 2024 - 04:28 AM

Hi guys, I'm a newbie here, so thank you for letting me in.

 

You write "click on the symbol by the layer title, and select mean". I have Affinity Photo 2 v 2.4.0 but I haven't found "mean". Without listing them all, the closest I found is "Average". What do I miss?

 

Thanks



#18 jdj

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Posted 13 May 2024 - 06:23 PM

On your Live Stack Group right under the word "Live" you will see a little symbol.  Click on that symbol and a menu will pop up with a series of options, including Mean.  You can see this in the screengrab in the original post in this thread.  The symbol 'mu' is seen which is for the mean combination approach.


Edited by jdj, 13 May 2024 - 06:25 PM.




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