A Complete Milky Way Composite Workflow (Siril + Affinity Photo)
If you’ve ever stood on a headland in South Devon, Dorset, or Cornwall watching the Milky Way rise over the sea while your camera quietly clicks away, you’ll know the magic of the moment. But you’ll also know the reality: coastal haze, light pollution gradients, noisy foregrounds, and the eternal battle between “what the sensor saw” and “what your eyes saw”.
Today's post is my complete, end‑to‑end SUMMARY milky way editing workflow for producing a clean, natural Milky Way composite using Siril for sky processing and Affinity Photo for blending and finishing. It’s the workflow I used this summer - refined, tested, and now written up so you can follow it step‑by‑step.
It has been trialled during my 'summer marathon' of milky way shooting across various national trust coastal landscapes in Devon and Cornwall - you can read about that here: https://undersouthwestskies.blogspot.com/2026/09/milky-way-astrophotography-across.html
As always, I add a proviso - this is my approach - I think everything is in the correct scientific order, and every tool or script includes a short explanation of what it does - but, I'm bound to be wrong somewhere - so please, if you spot an error - drop me a comment so I can correct things.
If you want to see my previous blogs about taking milky way landscape images - start here - https://undersouthwestskies.blogspot.com/2025/08/a-beginners-guide-to-post-editing-your.html and https://undersouthwestskies.blogspot.com/2025/03/an-equipment-check-list-for-milky-way.html and https://undersouthwestskies.blogspot.com/2025/02/beginners-guide-to-taking-your-first.html
But back to today's post - let’s dive in.
Firstly, my Milky way editing workflow is based on using affinity photo version 1 and SIRIL version 1.4.4
Secondly - I never take single image milky way landscape photos. Mine are always a composite blend comprising a separate sky image and a separate foreground image.
My normal 'in-the-field' work flow is: blue hour foreground shoot and a later total dark sky forground shot. Between, I take a mix of tracked shots and non tracked shots - ready for later stacking.
Hence my normal milky way images can sort of be described as TRACKED - STACKED - COMPOSITES
You can find details about my new Nomad tracker, by the way, here:
https://undersouthwestskies.blogspot.com/2026/08/the-move-shoot-move-nomad-star-tracker.html and https://undersouthwestskies.blogspot.com/2026/09/msm-nomad-star-tracker-review-update.html
Part 1 - PREP AND STACKING MILKY WAY IMAGES in Affinity Photo or Sequator
Get your sky and foreground files organised. Clean inputs = clean outputs.
Sequator: Aligns stars, freezes the ground, reduces noise.
Affinity Photo: New Stack → Auto‑align ON.
Stacking gives you a smoother, cleaner sky before Siril gets involved.
(This is where the scientific order really matters.)
Removes light pollution gradients and vignetting.
Smooths uneven sky brightness.
Final gradient cleanup.
Sets scientifically accurate colour balance while the image is still linear and untouched.
This step must happen before star separation, stretching, sculpting, or noise reduction.
Creates a clean starless layer for sculpting the Milky Way band.
Isolates stars for later recomposition.
Stretches faint Milky Way detail while protecting highlights.
Fine‑tunes contrast in linear space.
This is where the Milky Way comes alive:
Veralux Alchemy — global dust lane shaping
Vectra — local contrast sharpening
Revela — colour separation and richness
SyQon Prism — tone shaping and highlight/midtone balance
SyQon Parallax — depth enhancement and band/background separation
Silentium — detail‑preserving denoise
Nox (light) — smooth remaining noise
Mild curves, mild colour balance, optional tiny Vectra. Just enough to make the stars look natural — never sculpt stars.
Merges stars and starless layers cleanly.
Save Sky Final / Starless / Stars.
Exposure, noise reduction, colour balance.
Place the sky layer below the foreground layer. Mask the foreground to reveal the sky underneath.
Layer mask → soft brush → feather. Blend the horizon naturally.
Radial mask: targets the Milky Way band
Linear gradient mask: controls background sky brightness
Invert mask: refine background sky only
These masks give you selective control over the sky without touching the landscape.
White Balance → Selective Colour → Curves → HSL. Unifies sky and foreground so the composite feels natural.
Clarity → Contrast → Dodge/Burn → Unsharp Mask. Adds the final punch and definition.
Denoise → Frequency Separation.
Curves → Colour Balance → Vibrance.
16‑bit TIFF master + JPEG web.
For readers who love the technical detail, here’s why the sculpting tools appear in the exact order they do:
Sets the global structure of the Milky Way band: macro‑contrast, dust lane shaping, and initial definition. You must establish the big‑shape structure before applying finer contrast or colour tools.
Enhances local contrast and micro‑structure. Vectra works best after Alchemy has already defined the major dust lanes.
Refines colour separation and tonal richness. Colour refinement must come after structural contrast work; otherwise colour becomes distorted.
Tone‑shaping tool that balances highlights and midtones. Tone shaping must happen after structure and colour are already established.
Adds depth perception and separation between the Milky Way band and background sky. Depth tools must be applied last, once structure, colour, and tone are finalised.
This order is the backbone of a natural‑looking Milky Way.
This workflow is the result of many late nights on Dartmoor, many coastal sessions in Dorset, and many cups of tea while staring at Siril progress bars. It’s designed to be practical, repeatable, and friendly to real‑world conditions — haze, gradients, noise, and all.
If you follow it step‑by‑step, you SHOULD get a clean, natural Milky Way composites that still feel like the night you experienced.
However, as you can see from my 'evaluate the image' posts - it hasn't quite worked out the way I thought it would in my head or from following this work flow. But, over the winter, it is something I will endeavour to put right - expect some updates to this post work flow then!
If you have any thoughts about the work flow or the way I edit my photos - then drop me a comment in the box below so that other blog subscribers and readers can see it and learn from it - and thank you for taking the time to help me learn further - appreciated.
As always, have fun out there, keep looking up but stay safe.
Steve
aka #plymouthastroboy
If you are beginning your astrophotography journey and want some tips on night time safety - check this post here: https://undersouthwestskies.blogspot.com/2026/09/a-personal-safety-guide-for-astronomers.html
if you want to read my previous posts on taking milky way landscape images - read this post and the following six after it: https://undersouthwestskies.blogspot.com/2025/02/beginners-guide-to-taking-your-first.html
