D-76H is a hydroquinone-free variant of D-76 (the most commonly used film developer out there). Leaving out the hydroquinone is a good thing, as it isn’t the healthiest stuff around (it is a suspected carcinogen). Re-usability is said to be inferior to D-76, but it keeps longer without pH increases, and is easy to mix. Developing times and contrast indices are supposed to be identical to D-76. I hope to try it very soon.
Start with 500 ml distilled water at 50C
2.5 g metol
100 g sodium sulfite (anhydrous)
2.0 g borax
Make up to 1 L with distilled water
The best online information about D-76 can be found at Ryuji Suzuki’s wiki about it.