Using raw images from the NASA Juno probe- Jovial is the product of the images collected during flyby 18 (Perijove 18). Created on 23rd March 2019 Jovial awoke and is available for sale as prints on T-shirts, posters, canvas, tapestry etc… The original, unprocessed RAW image files are available directly from NASA: Image-set 6581.
Jovial began life in GIMP, the free image processing tool available for Windows and Linux. The process of combining the multi-channel greyscale images from JunoCam is fairly straight forward with GIMP. The best way to get started is to unzip the JunoCam images into a folder and drag only the three files suffixed with red, green and blue into GIMP.
View RedHeat’s JunoCam contributions on the official JunoCam Gallery.
View [Jovial] on the Store
Color -> Components -> Combine
Once all three images are open in GIMP, the process of combining them into a composite will require you to navigate the Color menu. Click Color, then Components then Combine. You should be prompted with a RGB file-selector dialog. Set the Red channel to the ‘-red’ suffixed file, the Green channel ‘-green’ and so forth. This step completes the creation of a composite image.
Now the tricky part is tweaking the image brightness, contrast, tone, color temperature, color curve adjustments per channel, sharpness, scaling (always scale up, I use the NoHalo scaler in GIMP) and so forth.
This isn’t easy for a newbie so will require some patience and experimentation, but it is totally possible to get great results with GIMP alone. Once you are happy with your image, upload it to the the JunoCam processing gallery! Good luck!