Safe to use Durst M605 CLS as a continuous light source (210 min) for DSLR film scanning?

[lukajaku]

Hi everyone,

I recently got a Durst M605 with a CLS color head and a TRA 305N transformer, and I’m planning to use it temporarily as a light source for DSLR scanning of color negatives (I had issues with the Kaiser Slimlite Plano).

Before I start, I’d really appreciate your advice on heat safety and workflow.

Do you think it’s safe to run the enlarger light continuously for about 2–10 minutes at a time to scan as many frames as possible, then let it cool for 20–50 minutes between sessions?
Or would it be better to use a digital timer (like the Kaiser one) and only power it on for the actual exposure duration that the camera needs for each frame?

The bulb is an Osram 100 W 12 V EFP 64627. I don’t have a digital timer yet, so I’m wondering if using it this way temporarily (continuous light for scanning, not printing) could risk melting internal parts or damaging the color head, or if this is generally safe as long as it’s allowed to cool between sessions.

Any first-hand experience with this setup, especially from those who’ve used the M605 CLS for scanning or long exposures, would be really helpful!

Thanks a lot in advance.

 

[koraks]

In my experience you can safely run the bulb in the M605 for a couple of minutes at a time. Yes, the housing will get hot, but there shouldn't be any damage. I used to own this enlarger and I have done 1+ minute exposures with it in the past and/or had it run for several minutes at a time for testing purposes. I never had any trouble with it.

However, I would recommend not using an enlarging light bulb for this purpose because of the shorter lifetime these bulbs are designed for. Since the filaments in these bulbs run significantly hotter (to reach the desired color temperature) than in an ordinary halogen bulb, the lifetime is also dramatically shortened compared to bulbs for interior lighting etc.

For a camera scanning setup, at this moment a LED light source is the most sensible option. I would contend that trichromatic narrow-bandwidth light sources (i.e. RGB) are a better option for camera scanning than a broad-spectrum light source. If you want to use a broad-spectrum light source due to considerations of simplicity, then I'd just pick a white LED source (bulb, COB, strips if need be) with a decently broad spectrum (although the importance of this is debatable).

I had issues with the Kaiser Slimlite Plano

What kind of issues?

 

[Chan Tran]

I think the bulb for my enlargers Beseler 23CII, 45MX and CB-7 dichoic heads are rated for only 50 hours. For use with camera I would want a light source close to 5000K and don't need all that bright because long exposure time isn't a problem.

 

[MattKing]

FWIW, electronic flash is another very interesting option, provided it is implemented properly.

 

[Chan Tran]

FWIW, electronic flash is another very interesting option, provided it is implemented properly.

Electronic flash is fine. Determining exposure is easy with the digital camera. Just needs to diffuse it well. The problem is you still need a light source to focus.