Stack and finish a Milky Way image in Photoshop

The complete path from a folder of RAW frames to a finished image, without ever leaving Photoshop — and why each step comes where it does. The examples use the NightScape Lab panels.

1 · Shoot lights and darks

At the tripod: shoot 10–20 light frames of your composition — same framing, same settings, back to back. Then cap the lens and shoot ~10 dark frames at identical settings before the sensor temperature drifts. The darks capture what your sensor does on its own (hot pixels, amp glow) so it can be subtracted instead of smoothed over.

Tip: darks are optional but cheap — five minutes at the end of the shoot buys you calibration that no amount of software cleverness can reconstruct later.

2 · Stack in the Stacker panel

In Photoshop, open the NightScape Stacker panel and choose Calibrated RAW (the From RAW files tab). Point it at your lights, add the darks, and set delivery to “Save master & open.” The engine dark-calibrates in Bayer space (before demosaic — the scientifically correct place), aligns the sky, and integrates. It runs in the background: keep culling, keep editing, Photoshop stays yours.

Tip: the panels lock while a stack runs — one engine, one job — but nothing else does. A typical 20-frame stack is a coffee's worth of waiting you don't have to watch.

3 · Meet the linear master (it's flat on purpose)

The stack opens as a Photoshop document: 16-bit, linear ProPhoto RGB, correctly ICC-tagged. It will look dark and flat. That is correct. No tone curve or noise reduction has been applied — every photon is still there, waiting for your development. If a stacker's output looks “finished” out of the box, someone else already made your aesthetic decisions.

4 · White balance and first tone

Open the NightScape Lab panel — the tools are listed in the recommended order, and White Balance is first. Because the master is linear and correctly tagged, white balance is simple channel arithmetic and it just works — that's the point of the deliverable. Neutralize the sky background, then bring the Milky Way up out of the linear darkness with a gentle Curves or Levels move — normal Photoshop development, nothing more exotic than that.

Why WB first: every judgment you make after this — "is that airglow or a cast?" — depends on accurate color. Fix the color of the light before anything else.

5 · Light Pollution

The second tool removes the sky gradient — the structured glow from towns and airglow that stacking faithfully preserves. It fits the gradient per channel and subtracts it. Skip it if you shot under a truly dark sky and the background is already even.

Check yourself: look at what's being subtracted. If you can see Milky Way structure in the removed gradient, you've over-fit — back off and re-run.

6 · Stars — reduce or remove

Separating stars from sky lets you work each without hurting the other: develop the Milky Way's structure without bloating stars, or dim a shouting star field so the nebulosity reads. Reduce for most nightscapes; remove entirely only when you plan to work the starless image and blend the stars back at taste. Skip this step entirely if your star field already sits where you want it.

Restraint: a sky with no small stars reads as fake instantly. Reduction almost always beats removal, and bright anchor stars should keep full strength.

7 · Defringe

Purple and green fringing on bright stars is easiest to judge on near-final tonality, and the earlier steps can shift it — so it comes last in the panel order. Inspect the brightest stars at 200%. Skip it if your lens is clean.

8 · Develop it yourself

Now the fun part, and it's all Photoshop: curves, color grading, dodge and burn, local contrast, the foreground blend — your layers, your masks, your taste. This is exactly the step one-click tools take away from you, and exactly the step the linear master preserves. The technically clean file is done; the photograph is yours to make.

9 · Save the finish as a Recipe

Like how the finish came out? Save the Lab tool sequence as a Recipe. The next frame from that night — or that camera, or that sky — gets the same treatment in one step, and you spend your time on the development instead of the plumbing.

Tip: keep one recipe per shooting condition (dark-site, suburban, astro-modified camera). Recipes carry the corrections, not the taste — the develop pass stays yours every time.

Asset needed — P1

Step-by-step screenshots

Each step needs a real screenshot from the shipped panels in Photoshop: the Stacker panel mid-run, the flat linear master on canvas, each Lab tool before/after, and the Recipes tab. Production spec: actual UI captures at 2x, cropped to panel + relevant canvas, consistent test image throughout.

All nine steps, without leaving Photoshop.

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