Turns out pieces submitted to NG will have their colors muted just the tiniest bit. This probably isn’t unusual for art-sharing sites like this, but just be aware if you’re particular about colors. Keep the un-submitted version on you, I guess.
On the left is the original picture. On the right is the picture taken from the submitted piece.
pepperly
If you're using any kind of unusual colorspace (ie: adobeRGB, CMYK, procreate's P3) there tends to be a conversion to the web-expected sRGB on most websites.
Kerriska
I use Autodesk Sketchbook, but obviously like you say, it must be using an unconventional color system. Thank you for your expertise.