From the amnufacturer:
SPUR NHC is a new, innovative high contrast developer for black-and-white negative films. Its area of application are the development of subjects with low or very low subject contrast (in the woods, at twilight, in foggy weather etc.) and the realization of graphic effects with reduced tonal values with normal or higher subject contrast.
The developer stands out by the following features: extremely high sharpness as well as high resolving power in conjunction with rather fine grain considering the contrast attained. Speed yield is at least box speed or one f stop more depending on the contrast attained.
Exposure latitude is very large in view of the high contrast. Due to careful coordination of those features of the developer that have an effect on the suitability of the developed negative for scanning, negatives developed in NHC are easily scanned.
The sample photos on our website are raw scans, i.e. those samples have never been subject to digital image processing except perhaps a slight optimization of brightness. The times for the tray development of sheet films as well as rotation processing must be determined by the user.
Different emulsions developed to attain the same contrast may react completely differently as far as extreme highlights are concerned. Byway of example, extreme highlights are rather moderate with Kodak Tri-X and Ilford FP4+, whereas they are substantially steeper, e. g. with Ilford Pan F+ and Kodak Tmax 100.