question for darkroom enlarger-use
I've got two occassion enlargers .1, crocus 66 en 2, Durst 805
The durst is the one I 've bought now. The lamp was broken so I put a ordinary 25 watt in it in attendation of a new original 100 watt .So when I'm using the both on AGFA PREMIUM GLOSSY MC paper the times are incredible long (up to 15 minutes ) and the enlargement is very low in contrast and tones . Very softly ! Shall I need to use filters? or the FILTER system on the durst or is it the paper that is too old ?
Can anybody tell me how I can change the lamp in the durst . Along the notes delivered with the Durst must it be possible to open it above just where the lamp is .I've spend three hours to get the bad lamp out of it .
I had to screw the system that hold the lamp and the mirror before the lamp out of the Durst head. What is happening if I use a LED lamp in it ? To little light too?
Thanks for helping me
According to the Durst catalog, the M805 B&W takes 150W opal lamp and the M805 Color a 250 W halogen lamp (Colamp 250 S). So 25 W is very underpowered, hence the long exposure times. The color spectrum of the bulb is important when using MC paper. The low contrast you are seeing suggests that the bulb temperature is too low, resulting in a preponderance of red light, to which the paper is not sensitive, and green light, which will only activate the low contrast emulsion on the MC paper. This would probably be the case with an ordinary incandescent bulb. Halogen bulbs are better since they operate at a higher temperature, giving more energy in the blue part of the spectrum which the high-contrast emulsion in MC paper is sensitive to. The problem with using a filter to correct this is that your exposure times, which are already long, will increase even more, especially if your bulb is an ordinary tungsten incandescent with little blue light to start with - a filter won't add blue light, it can only take away the excess green! My suggestion would be to see if you can't fit a 100W (or more powerful) halogen bulb.