We use PayPal as it automatically provides the verified details we require for license generation. However we understand not everyone has (or wants) a PayPal account.
Bin the image up until each pixel describes one unit of real detail.
With a suitable dataset, workflows in StarTools are simple, replicable and short.
However the Synth module can physically model and emulate most real optical systems and configurations to obtain a desired result.
The actual "useful" noise grain, much like dithering, however may be visible when zoomed in at scales beyond 100%.
You can convert everything you see to a format you find convenient. Give it a try!