Too short exposure time

[ignacj]

I'm having a problem with very short exposure times (under 2 secs) on my 45M. Following is the setup...

Beseler 45M (condenser)
150W bulb
no filter
f16 aperture
Adorama VGRC paper (ISOP 640, grade 2 without filter)
Dektol 1:2 (~1 min dev time)

I am getting a new 75W bulb, but I don't think this will significantly increase the exposure time. I'm also considering ND filter, but I cannot locate correct size (under the lens type). 45M does not have filter drawer as newer models (contacted KHB if retrofit is possible).

Negatives (35 and 120) are exposed/developed correctly and look fine when scanned on Epson.

Any suggestions are greatly appreciated!

Thanks
ig

[nworth]

I run into this problem with my 35mm enlarger. My solution was to put a neutral density filter in front of the lens.

[Ben Taylor]

I had a similar problem some years ago, discovered the fault was with my enlarging lens.

The lens had a ring you twist to fully open for focusing. I eventually discovered that when I turned this ring back to stop the lens back down to my selected aperture it would only party close the aperture blades, so I was using a much wider aperture than I thought. The solution was to focus first with the widest aperture selected, then stop the lens down.

[Ronald Moravec]

Put some tracing paper or make a ND filter from 4x5 film exposed to Zone 5 and put it above the condensers.

Buy an Aristo variable resistor. Expensive but well made. Good for 3 stops.

Make a resistor from a wall dimmer and 4 way box.

I find it very hard to believe you don`t have very thin negatives. Hold one up to a 60 watt bulb and look thru the darkest part. You should block most of the light.

If you are detirmining a neg is good by how it scans, you should revise your method and contact print it on #3 paper. That will give you a decent scanning neg depending on the film as some films scall better than others although they can print correctly.

[Mainecoonmaniac]

How about an ND filter above the negative near your light source. Rosco, the maker of theater light gels makes ND filters one, two and three stop increments. http://www.amazon.com/Rosco-Cinegel-.../dp/B000B73PBS The gels are made for hot lights.

Good luck!

[ignacj]

Ben,

I can see aperture changing diameter as expected when off the enlarger. I do not think I have any additional controls that would prevent it from closing when on the enlarger.

Ronald,

Negs are fine. Dark areas are dark as you describe. Instead of using wall dimmer, any reason not to use a corded night-lamp remote dimmer with enlarger? Thanks

Mainecoonmaniac,

I use Rosco color gels with my studio lights and was not aware they made ND gels as well. I'll give it a try! Thank you!

[fotch]

The 75w bulb should double the exposure. A light dimmer is worth a try, the night light one you spoke of, just make sure it will handle the wattage.

[Sim2]

Hallo,

I have experienced a similar problem with my enlarger. I have used it for 35mm (with a 35mm neg mask) and only recently started to use it for 6x6 (with a 6x6 neg mask). The times for 6x6 have been considerably less than with the 35mm - I have put this down to the amount of light available to be passed through the 6x6 neg is greater than the amount of light available to the 35mm neg, condensers cannot be adjusted for different neg sizes.

The Rosco ND filters were suggested to me in my thread, and that is a route that I will be exploring shortly.

Dimming a bulb might result in colour temperature shift which may affect the response of variable contrast papers.

Sim2.

[ignacj]

Sim,

35 to 6x6 move make sense. The problem is that even my 35mm are around 2.5 - 3 seconds exposures.

My only concern about *mart type of dimmers is to the fact that they are TRIAC based (pulsating current) and how could that affect enlarger (beside possible temp shift). I already have a couple of them, so I'll give them a try (with VC paper) in next couple of days. ND gels are on the way. I'll report back how (and if) it all works out.

ig

[timk]

make sure the bulb is the correct type for your enlarger, and that the power supply is correct.

What size are you enlarging to? The smaller the print the shorter the time.