HP5+ works very well in Microphen or DD-X, giving a real speed of EI 640 and a nice push to EI 1200-1600 without getting nasty. While Microphen is normally used straight and DD-X is diluted 1:4, they work just fine at 1:1 and 1:9 respectively, giving equivalent curve shapes and speeds to the stronger dilutions at development times of around 1.5X the normal times.(posted 8408 days ago)This can really be a toss-up; at EI 1200-1600 HP5+ begins to get a little contrasty, while Delta 3200 at those speeds offers superb tonality but is significantly grainier.