Best enlarger timer

Melvin J Bramley · Apr 2, 2023

In previous years and with simpler , less powerful, enlargers using a enlarging timer that timed in seconds and minutes was not an issue.
I am now faced with much more efficient light sources that are giving me exposure times of about six seconds at F11 printing an 8 x 10.
This gives no 'real' time to manipulate the exposure.
Short of figuring out some sort of ND filter how can I rectify this?
The bulb in my LPL C670 is an odd size physically , it's much smaller than a regular enlarger bulb si It's not easy to just reduce the wattage.

Are timers that time to half of a second necessary?

TB

MattKing · Apr 2, 2023

Which light source is that?
With the US and Canadian model numbers being different, it can be confusing, but I don't recognize "LPL C670".

Buzz-01 · Apr 2, 2023

If you do dodging and burning, 6 seconds is rather short. At least it is to me.
An ND filter would probably be my weapon of choice here...

But, as per your question, iirc the Philips PDT024 had a scale knob where it would let you alter the base timing. Like 0.9x would make every second 0.9 seconds.
I'm not sure what the range of that scale was though.
But there are probably more timers out there that can do something similar.

snusmumriken · Apr 2, 2023

Could you not wire a dimmer switch into the enlarger supply? If you are using an LED bulb you would need an LED dimmer, but they are widely available. There are even up/down touch button switches.

Buzz-01 · Apr 2, 2023

If it's LED then that could be a good solution!
But if you're using a regular tungsten bulb then be aware that the color temperature of the light may change when dimming the bulb.
That will most likely mess up your print grades.

Could you post a picture of the bulb perhaps? Maybe some users can point you in the right direction?

Nicholas Lindan · Apr 2, 2023

FWIW the Darkroom Automation f-Stop timer's lower limit is -2.8 stops which translates to 0.18 seconds (0 stops = 1 second). It controls exposure time in 8.333 millisecond intervals, equal to a half cycle of AC power at 60Hz.

I don't know the specifications for the RH designs f-stop timer.

All that said - the solution to your problem is an ND filter. Rosco filters work very well for this - https://www.bhphotovideo.com/c/product/163137-REG/Rosco_102302992124_E_Colour_299_1_2_Neutral.html
And they are far cheaper than using a camera filter. The filter goes in the enlarger's filter drawer, although optically they are good enough to use under the lens.

As there is confusion over the enlarger you are using - might it have a dichroic head with three knobs for cyan/yellow/magenta filters. If so, then you can attenuate the light by dialing in all three filters.

Huub · Apr 2, 2023

I would suggest using a ND filter to get your times up, dodging and burning being essential darkroom techniques. It is at least what i do when times get shorter than 10 seconds. A dimmer might also work, but i don't have personal experiences using such a device.

FriedLouisStudio · Apr 2, 2023

We always had a rheostat or dimmer in the circuit along with a Time-O-Lite timer on our Omega D3v (standard condenser with traditional incandescent enlarger bulb). There were definitely times when we would want to dim the light source separately from the lens f-stops. As far back as I can remember (early 60s), there was always a rheostat next to the timer.

Obviously, lots of today's light sources are a different from the old-school enlarger bulbs, and color printing has different concerns. But in my experience, using a dimmer was a legit way to handle too-bright/too-short exposures in b/w.

Bill Burk · Apr 2, 2023

Buzz-01 said:
If you do dodging and burning, 6 seconds is rather short. At least it is to me.
An ND filter would probably be my weapon of choice here...

ND filter in the enlarger is my choice too. An 0.6. Wratten ND sits nicely atop the lens, and you can still see what you are doing. You can also increase your camera exposure. Two stops greater camera exposures will give roughly double print time (compared to perfectly exposed negatives).

ic-racer · Apr 2, 2023

The bulb in my LPL C670 is an odd size physically , it's much smaller than a regular enlarger bulb

If you have the 100W, 12V lamp of the NON-USA C6700 (in picture below), I agree it is a little oddball. Smaller than the usual MR-16 style, probably MR-11. Which head do you have? That will determine how to best implement neutral density to diminish printing times.

A variable output 12V power supply would probably be my least favorite choice due to the complexity of implementation, and its effects on color temp of the lamp.

Ian C · Apr 2, 2023

Here are some more comments about some older models of LPL enlargers. Apparently, LPL used the following codes:

C = condenser

D =dichroic

XL = extra-long column

http://www.jollinger.com/photo/enlargers/lpl.html

So the C670 would be the condenser version.

Using a neutral density filter is a safe and easily controlled way to get longer printing time. ND filters are most commonly made as:

ND 0.3 = 1 stop, 2X the unfiltered exposure time

ND 0.6 = 2 stops, 4X the unfiltered exposure time

ND 0.9 = 3 stops, 8X the unfiltered exposure time

Most, but not all, enlarger lenses are equipped with front threads that accept screw-in filters. You could buy a filter of that threading. Or you might choose a filter to fit your camera lens and use a step-up ring when you want to use it on the enlarger.

By consulting Freestyle Photo’s enlarger lamp guide, we see that the LPL 670CXL uses the common small size 75-watt PH-140 screw-in opal photo lamp.

https://www.freestylephoto.com/enlarger-bulb-chart

I think that using a neutral density filter on the lens is the cheapest and most practical way to lengthen your exposures for dodging and burning.

ic-racer · Apr 2, 2023

Looks like they call the Dichroic head C6700 and the condenser version takes a standard screw lamp which is not in the OPs enlarger. So we really need a picture of the OPs enlarger to know.

Melvin J Bramley · Apr 2, 2023

MattKing said:
Which light source is that?
With the US and Canadian model numbers being different, it can be confusing, but I don't recognize "LPL C670".

LPL condenser model 670 CXL..

MattKing · Apr 2, 2023

Melvin J Bramley said:
LPL condenser model 670 CXL..

Thanks - here is the incandescent bulb:

MattKing · Apr 2, 2023

Ian C said:
Most, but not all, enlarger lenses are equipped with front threads that accept screw-in filters. You could buy a filter of that threading. Or you might choose a filter to fit your camera lens and use a step-up ring when you want to use it on the enlarger.

You might prefer to substitute a ND filter for a below the lens red filter - to make it easy to switch the filter out when setting the cropping and focusing.

Doremus Scudder · Apr 2, 2023

Six seconds for an exposure is simply too short if you need to do any dodging at all. So, don't accept that. Figure out a way to get longer and more comfortable exposure times instead of investing in a fancy-dancy more-expensive timer that won't get rid of the inherent problem of a too-short exposure time. You'll be glad you did.

So, find a not-as-bright bulb, use a ND filter, dial in equal amounts of magenta, cyan and yellow on your dichroic head (equals ND), stop down more or whatever.

FWIW, I like exposure times in the 20-30 second range.

Best,

Doremus

Steve906 · Apr 2, 2023

My Durst modular 70 has a variable iris-ish (2blade) thingy on the light source just in front of the lamp (12v 100w) giving continuously variable illumination. Don't other enlargers have similar ? Maybe you could just use a metal plate with a hole in it of suitable size to do the same?

ic-racer · Apr 2, 2023

Steve906 said:
My Durst modular 70 has a variable iris-ish (2blade) thingy on the light source just in front of the lamp (12v 100w) giving continuously variable illumination. Don't other enlargers have similar ? Maybe you could just use a metal plate with a hole in it of suitable size to do the same?

Looks like he has the condenser model in which case anything in between the bulb and printing paper can show in the print. A clean ND filter is the way to go.

cliveh · Apr 2, 2023

Durst Digital Labotim enlarger timer

Durst Digital Labotim enlarger timer in good working

www.profilmdirect.co.uk

Steve906 · Apr 2, 2023

ic-racer said:
Looks like he has the condenser model in which case anything in between the bulb and printing paper can show in the print. A clean ND filter is the way to go.

Ah OK I was for some reason thinking it was dichroic head. Would probably need aperture to be between the two condensors - so not really do-able easily.

Don_ih · Apr 2, 2023

Check if your prints come out good with your lens stopped down another click or two. That will depend on the lens.

Or - get a longer lens. A 60mm lens will get your enlarger head farther away from the paper (assuming you're using a 50mm on a 35mm negative).

Those ND filters look like a great option, though.

randyB · Apr 2, 2023

I've had situations like this in the past. I solved the problem by cutting some plastic diffusion material to fit on top of the upper condenser lens. I recycled a thin flexible plastic CD cover that had perfect diffusion. Nowadays you have the option of using an LED bulb (40 watt or smaller) that should fit in the lamp house, provided your enlarger uses the PH140 bulb. I agree with the others, you need longer times for dodging and burning. (25-45 sec).

Melvin J Bramley · Apr 2, 2023

randyB said:
I've had situations like this in the past. I solved the problem by cutting some plastic diffusion material to fit on top of the upper condenser lens. I recycled a thin flexible plastic CD cover that had perfect diffusion. Nowadays you have the option of using an LED bulb (40 watt or smaller) that should fit in the lamp house, provided your enlarger uses the PH140 bulb. I agree with the others, you need longer times for dodging and burning. (25-45 sec).

The plastic diffusion may also create a 'semi' diffusion enlarger.
I did similar many many years ago with a Durst.
Thanks for the reminder...

TB

Kilgallb · Apr 2, 2023

ic-racer said:
If you have the 100W, 12V lamp of the NON-USA C6700 (in picture below), I agree it is a little oddball. Smaller than the usual MR-16 style, probably MR-11. Which head do you have? That will determine how to best implement neutral density to diminish printing times.

A variable output 12V power supply would probably be my least favorite choice due to the complexity of implementation, and its effects on color temp of the lamp.

The lamp shown is no doubt a halogen type. Dimming a halogen
lamp causes it to run too cool and the glass blackens causing the lamp to blow.

mshchem · Apr 2, 2023

Melvin J Bramley said:
The plastic diffusion may also create a 'semi' diffusion enlarger.
I did similar many many years ago with a Durst.
Thanks for the reminder...

TB

Don't put plastic above the condensers, it can melt. I would get a Darkroom Automation F stop timer. The inventor is right here if you need help. Pricing is quite reasonable. Once you have used a f stop based timer you will understand why these are so popular.

If you want to increase time I would find a neutral density filter a gel in the filter drawer or even a screw-in type filter fitted to your lens. Most lenses are sharpest 2-3 stops down from the maximum aperture.

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