By the use of weak-hardened papers the gelatin can strongly swell if the development times lie more than from three to four minutes. Then with the following shading it can come to an colouring of the gelatin. The hardener concentrate can be added to the stop- or fixer- bath, with the disadvantage of extended wash times. A hardener bath (one minute with thinner 1+5) after a pre watering of approx. 10 minutes is more sensibly. After the harding the surface is closed, protected against mechanical injuries and the picture-white remain clean with shading. The hardener is sour, befores hadings the acid should be neutralised either by a slightly alkaline watering help, or be removed by a short watering from the layer.