Dilution H is an "unofficial" dilution of Kodak HC-110. To make Dilution H simply dilute the standard Dilution B with double the amount of water (mix 1:63 from USA concentrate or 1:19 from European concentrate). Dilution H is half-strength Dilution B. For starting point times, use double the time listed for Dilution B. This is useful if you prefer longer, more controllalble development times, are seeking to improve tonality and contrast, or just want to improve the economy of the developer. Most users report very little difference in results between these dilutions.