About why the print looks to red, I have no answer .
I only have questions....
1.Are you using the same settings as you are when printing on the 190g??.
2.Are you printing the same Image???and the 300g comes out more red???
3.Do you have a calibrated display???
the printer doesn't seem to be able to get all the detail on paper...
The user manual of the printer says not to switch the handle of the print head to the right (only for envelopes, etc.)
Anyone has experience with this situation?
What printer are you using???
Normally(if you're on a Epson 2100/2200)when printing an thick media(300g is what I call thick)
You need to load the paper from the "rear" moving the "slider/handle" way down to the bottom(the same mode as you use when printing on cd's)
Then when the paper is in "place",Move the "slider/handle" to the "envelope" position