Also, on stamps that have lots of solid surface I have found the quality of paper to be important.
Example, trying to stamp an ornament from the SU set Delightful Decorations. I could NOT get the solid parts to come out SOLID. Re-inked my pad, tried different padding under the paper, tried putting the paper on top of the stamp. Finally switched from SU's Confetti Cream to SU's Very Vanilla...and "poof"...solid image. The ultrasmooth surface of the Very Vanilla ( or Whisper White ) gives a much better solid image than the other neutral papers.
Mary in NC