Image processing tools: Affinity becomes free and gains a new astrophotography feature (+ Tutorial)
Quick summary· AI-generated
Affinity Photo (formerly a paid application) is now available for free on Windows and macOS with an integrated Tone Stretching tool designed for astrophotography. The article explains the fundamentals of post-processing RAW TIFF files from smart telescopes like Vespera, covering why linear RAW data appears nearly black when opened in image editors and how tone stretching redistributes histogram values to reveal faint nebulae and galactic details. Affinity is positioned as a complementary tool to specialized astrophotography software (PixInsight, Siril, AstroPixelProcessor) and supports native FITS files and astrophotography plugins like StarXTerminator and BlurXTerminator.
Excerpt from Vaonis - Our travel journal
Affinity Photo has long been a valuable complement to specialized astrophotography tools such as PixInsight, Siril, or AstroPixelProcessor. It offers native FITS support, compatibility with key astrophotography plugins like StarXTerminator and BlurXTerminator, and a fast, real‑time, non‑destructive workflow that lets you fine‑tune every step of your processing pipeline. Its sleek, modern interface makes it an excellent companion for smart telescopes like Vespera, where ease of use is key.
The new version, now simply called Affinity, is available on Windows and macOS — and it’s completely free. Among its improvements is an integrated Tone Stretching tool dedicated to revealing faint deep‑sky details.
Get Affinity
Download the app from the official website: affinity.studio
Introducing tone stretching: revealing the hidden details in your data
In astrophotography, stretching is one of the most fundamental and crucial steps of post‑processing. To understand why, let’s begin with what happens when you capture and open a RAW image.
RAW data: the foundation of astrophotography
Post‑processing should always be performed on RAW files rather than JPEGs or other compressed formats. RAW preserves the entire dynamic range recorded by your telescope’s sensor, from the faintest glow of a nebula to the brightest stars. JPEGs are already tone‑mapped, compressed, and potentially clipped; lost information in the shadows cannot be recovered. RAW keeps all the subtle signal you need for deep‑sky processing.
Why your Vespera RAW TIFF looks black
When you open a RAW TIFF from your Vespera (or any smart telescope) in an image editor, you might be surprised to see almost nothing. The image often appears completely black or extremely dark, even though your capture session was successful.
This happens because the file is still in a linear state, the pixel brightness values directly correspond to the amount of light recorded by the sensor, with no adjustment for human perception. The faint glow of a nebula may only be a few counts above the background noise, while stars are thousands of times brighter, but all that signal is packed into the darkest part of the histogram.
The same image before (RAW) and after stretchning
Linear data and the histogram
The histogram represents the distribution of brightness (intensity) values in your image, from black on the left to white on the right. In a linear astrophotography image, almost all the signal - galaxies, nebulae, faint…
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