I have been trying to do contact printing without an enlarger. I have a problem with my light source. My light source is those LED torch light. After I shine 3s and put it into the developer for 15s, the contrast is very high, like photocopied paper like that. Then i tried shining for 2s, then develop for 15s, the colours are some sort muddled. How should I control the printing? Should i keep the light intensity constant and vary the developing time? Or should i vary the light intensity and keep developing time constant? Are there any differences? If so, what are they?