You could be either; a) printing using the incorrect filter or no filter, b) using old, poorly-stored, degraded or lightly-fogged paper, c) using cold, exhausted or partly-exhausted developer, d) 'pulling' prints before they've fully developed, e) using a low-contrast print developer, f) trying to print low-contrast/underexposed negatives. It's possible that g) your camera lens, negative, enlarging lens or enlarger's optical path have accumulated dust/grease/condensation/other and need cleaning, or h) your paper is being fogged by your safelight or other extraneous light source.
Unless b), you don't need to 'learn' a new paper - MGIV RC will give the contrast you desire when your fault is corrected. If you can post some examples others might be able to offer more concise and pertinent information than me.
Last edited by kevs; 01-02-2013 at 10:11 PM. Click to view previous post history.