Smith Corona SM3 ink fading

[readhead]

I'm secretly using my dad's Smith Corona SM3, and the ink is giving me trouble!
When I start a paragraph, the print looks great and dark. But by the time I get to the end, the ink has faded to almost half the original shade!
Why is the ink lightening up so much as I type? Am I running the ribbon dry too fast, or is something else going on with the machine?

 

[crankyd0od]

You’re not imagining it. the SM3 can fade mid‑paragraph if the ribbon isn’t advancing every keystroke. Sometimes old ribbons also dry out unevenly. Check the ribbon movement while typing a few slow lines.