Dull, dull, dull...

Comrades,

I posted a quetion on the colour forum a few months ago about my Durst M605 colour enlarger.

It was giving out only a very dim light source, despite the filters swinging in and out properly, having a new bulb, and using a working lens operating at full aperture.

I received lots of helpful comments but alas, it was still taking one and a half minutes to expose a 10x8 black and white from a well exposed negative.

Colour was taking about the same.

So...I took the machine back to the 2nd hand camera emporium from whence it came and the chap (a knowledgable camera man) had a good look and declared if fully working.

But it clearly wasn't.

Therefore, he very kindly agreed to swap the enlarging head for another Durst M605 head which he just so happened to have in the shop.

I have been using this for the past few months now but I don't think that this one is bright enough either. Although it produces nice prints in colour and b&w, the exposure time to print a 10x8 is still very high - about a minute.

The filters all work properly and are clearly swinging in and out as they should. There is a brand new bulb in of the correct manufacture and wattage, and the lenses which I'm using (Minolta 50m 4.5 and Componon 80mm 5.6) all open and close correctly.

So...my questions are:

1. does anybody have any suggestions for how to brighten the enlarger?
2. would it be worth buying faster enlarging lenses to get the maximum brightness from the current set up?
3. aside from standing around in the darkroom for ages, do the longer exposure times really matter? I ask this because the ilford papers which I use are optimised for 10 sec exposures, and I daresay that Fuji and Kodak's colour papers are about the same.

Many thanks in advance for your help,

Roger

its your dichroic bulb, it will have the incorrect one installed or potentially your power supply is outputting the correct voltage. test it with a volt/ammeter .

this may be a dumb question, but are you sure that it is your enlarger, and not overexposed and/or overdeveloped negatives?

Roger, I don't know about the enlarger, but printing times longer than 10 seconds with Ilford B&W paper are the norm.

I nearly always have a minimum of 30-40 seconds if I can, for a base exposure, this gives me time to work comfortably. Conversely I sometimes do many prints at around 5 seconds exposing time with the same paper.

I also do some very big cropping, this entails exposures timed in minutes.

With colour paper, admittedly not the same stuff around today, exposures from 15 minutes to 25 minutes were the norm for mural enlarging. Then the next print with the same paper could be 15 seconds. The only difference was the filtration package for the films and the time.

Mick.

Thanks for your replies so far.

I should have added that I have been using the lenses fully open, and that the bulb inside the head is very bright when you have a look at it directly - to the extent that you can only do so for less than a second.

However, maybe it should be even brighter. The one constant factor between my last M605 and my current one has been the transformer. Do you think that this could be issuing a sub-standard wattage?

The transformer is a Durst TRA 305N.

I have a M605 and if my experience is anything to go by something is definitely wrong. The bulb should be 100W but I had to switch to 75W to increase the exposure time for RA4. It was only about 3 seconds. Even with B&W negs and a 10x8 print, a 75W bulb still gives me well under 20 secs with Y and M filtration in place and an aperture of f8.

Make sure the switch between 35mm and 66 is operating properly. It moves a different diffuser across the box and could be sticking in the middle thereby cutting out a lot of light. When you move the switch there should be a loud clunk noise. If there isn't or even if there is I'd take off the head and then watch the diffusers as you move the switch. Only that way can you be sure a diffuser hasn't stuck halfway.

pentaxuser

Which format film and which mixing box are you using that give the long times?
Is your TRA 305N set up appropriately for your mains voltage? I know the TRA 450 has taps on the transformer primary for 110v, 220v and 240v. Did they test the output voltage of your TRA 305N?

I'm using both the 35mm and 6x6 boxes, and the switch makes a nice chunky clunk when I move it from one to the other.

I don't have the transformer in front of me, but from what I remember it doesn't have optional outputs or switches - just an input and output. I wonder whether it's no longer giving out the correct amount of power - hence the dimness of light.

It would explain why I've had two dim M605s one after the other - unless this is a common complaint of this particular enlarger.

Roger2000 said:

It would explain why I've had two dim M605s one after the other - unless this is a common complaint of this particular enlarger.

Click to expand...

No it isn't a common complaint. I too have the transformer. Mine is fine but it may be that they can work but somehow reduce the power output. I don't know enough about transformers to say.

You appear to have checked out all the obvious faults connected to the enlarger such as the box, aperture on the lenses not working, filters sticking etc.

The common link seems to be the transformer. Presumably when you took it back to the shop they had to hook it up to their transformer in order to declare the enlarger to be OK. Unless you can obtain another transformer to try, it might be sensible to take your head complete with your lenses and bulb back to the shop and ask that it is connected up to their transformer. If it has a darkroom then one of your negs could be inserted to check on times but given how bad the light emission is, then it should be possible to see the difference in the shop with the naked eye so to speak.

pentaxuser