T-Max dev is normally diluted 1:4. I've used it a few times at 1:9 with HP5 (years ago) and it was overall a little better than the standard 1:4; it'd probably work ok out to 1:15 or so. Try doubling the standard 1:4 development time as a starting point.(posted 8261 days ago)T-Max dev tends to give negs with chunkier grain and less acutance than D-76/ID-11 1:1 to 1:3; personally I wouldn't fool with it again, but free is free and it'd probably be worth a test roll.