14 min exposure

Gast · 2004-12-15T15:05:59+00:00

Ich brauche Rat! Ich hab einen Durstvergrößerer, mit dem ich meine S/W-Fotos belichten will. Das Ding ist, dass ich bei einem Fotoformat 40x50 (also Linse-B...

Gast

I need some advice! I’ve got a contact printer that I want to use to develop my black-and-white photos. The problem is that, with a 40x50 cm photo (so the lens-to-image distance is about 90 cm), I have to perform an exposure for 14 minutes!! before I get a decent result. I’m a beginner, but I haven’t found any mistakes: aperture wide open, lamp as far in as possible, no filters. If I take the negative out and perform the exposure, the times are under a minute. What now? Thanks in advance for your replies!! Stefan

MirkoBoeddecker

Stefan, Have you perhaps experienced overexposure or overdevelopment of the film? How many watts is your bulb? Is the condenser clean? Is the lens clean? Are you perhaps using a 6x9 enlarger with a 105mm lens and a 6x9 condenser for 35mm film? Incidentally, you should stop down to f/8 because of the lens performance. Best regards, Mirko

fotohuisrovo

14 minutes for a 40×50 cm enlargement is far too long. Something must be wrong somewhere. In fact, stop down to 2F values for the lens performance. (2.8 → 5.6 or 4.0 → 8.0).

Are you perhaps using a 6x9 enlarger with a 105mm lens and a 6x9 condenser for 35mm film?

Yes, and with 35mm and a 50-watt bulb, you might just about manage that 14:00 min. time. :angry: Best regards, Fotohuis RoVo Robert Vonk

Gast

OK, I’ve had a look in the user manual and found the following information: DURST C35 enlarger, the lens is a three-element NEOTARON 2.8/50 mm, the lamp is 55 watts and the lamp holder is marked with a sticker to indicate this. The negatives aren’t actually over- or subject to underexposure. "6x9 condenser for 35mm" <-- I’m afraid I don’t understand that I opened the aperture as wide as possible, as that’s when the light intensity was subjectively strongest. I hope this information is helpful and leads to a solution In any case, many thanks PS: Can I get a more powerful bulb despite the socket?

cfb_de

Hello "Wegen",

can I get a high-intensity lamp despite the socket?

No. Unless you want to melt your negatives and watch the enlarger go up in flames. Best regards, Franz

fotohuisrovo

The Durst C35 isn’t suitable for these purposes. The system is too weak in terms of brightness, filter system, etc. If you were to be doing a lot of 40×50 or 50×60 prints, the brightest enlarger in this class is the Dunco. The exposure times would then be around 30–50 seconds. But perhaps Impex still has a Magnifax on offer somewhere. That would certainly do the job well too. Best regards, Fotohuis RoVo http://www.FotohuisRoVo.nl Robert Vonk