Timer recommendation for color work?

Thanks to all for the help so far, the equipment is slowly trickling in for the color dark room. I just modified my Agfa C66 (Durst M605) tonight so it can take an external timer now. The timer that was built-in was worthless...only for a certain type of Agfa paper, I think. I always just counted to myself when printing B&W (I know, far from efficient, but it worked for the most part).

I am ready to take my printing to a new level, and am investing a bit of money and time here, with all the equipment and garage space. I'm not going to skimp on the timer if it will help me be more precise, now that I've finally ripped into the electronics of the enlarger and it's possible to use a good one.
Any suggestions on that account? I saw an ad on here for the f-stop timer at Darkroom Automation and it looked pretty awesome. Are those about the best, or are there others I should consider? Obviously I'm coming from the dark ages on timers here...

One more question regarding a line-stabilizer for color work: Will any brand or type do? I see there is a Unicolor Voltage Stabilizer on Ebay for about $40. Is that any good, or should I be looking at something different? Never owned one of these before, guess they're not needed for B&W.
Thanks in advance, I always seem to get advice worth following here!
Have a good weekend,
Jed

Most of the better analyzers have timers builtin. The last Colorstar 3000 I bought didn't cost much more then just a digital timer would have. Some thing to think about.

Go for a Colorstar 3000. The best coloranalyzer you can get.

ferroresonant transformers are worthwhile

I found mine surplus, and it is only good for 250W, but the enlarger lamp is a much lower load than that. They are heavy, but there is nothing in them to ever go wrong, unless you over load them. Other stabilizers based on LC filter circuits can risk the capacitors drying out with time.

Jedidiah Smith said:

I saw an ad on here for the f-stop timer at Darkroom Automation and it looked pretty awesome. Are those about the best ...?

Click to expand...

Speaking as a representative of Darkroom Automation ...

Thank you very much for your candid assesment...

To assist in evaluating the timer there is a quick guide to the Darkroom Automation f-Stop Timer at

http://www.darkroomautomation.com/support/mfsquicks.pdf

It shows the basic steps in operating the timer, gives a feel for what it does and illustrates the steps in making burns and dodges. The quick guide doesn't cover memories or split-grade printing. The complete manual covering these topics should be on the website in a day or so. The operation shown is similar to that of the original Darkroom Automation timer, with a few exceptions.

The timer comes with a 30-day money-back guarantee, so you can make your own decision in your own darkroom.

(My version of Acrobat Reader needs to load the manual twice before it gets it right.)

Jedidiah Smith said:

One more question regarding a line-stabilizer for color work: Will any brand or type do? I see there is a Unicolor Voltage Stabilizer on Ebay for about $40. Is that any good, or should I be looking at something different?

Click to expand...

Speaking as an apug member:

Many enlargers, usually dichoric, that have a box that powers the head are already voltage regulated and you don't need to do anything extra. Sometimes this transformer/regulator box is hidden in the guts of the enlarger.

I am not familiar with the Unicolor regulator. If it was small and didn't have a knob on it then it may be similar to Wein's old regulator (~2x4"). The design has the peculiar characteristic that it can boost a low input voltage but can't reduce a high input voltage. (FWIW for the techies it was a phase-controled voltage doubler. It would be practical if you used 130V lamps.) The construction/design of the unit was a bit questionable.

There are 'voltage regulators' that have an adjustment knob and often a voltmeter. These are either variable autotransformers or power rehostats. They don't regulate the voltage but they do allow you to control it - you would have to shift the knob every time the refrigerator cycles if you want control.

Then there are UPS/Regulator boxes sold for personal computers. These are multi-tap transformers coupled to a voltage sensing circuit. The unit changes taps to keep the voltage within ~20% of nominal. 20% of nominal is no where near what is required for color printing - 2% is what is needed.

There is an enlarger voltage regulator from the 70's (80's?) that comes in small blue metal box, made in Rochester, can't think of the name of the manufacturer. I have no other information on it, but the firm seemed to know quite a bit about color printing.

The last practical alternative is a ferroresonant transformer. The 'harmonically neutralized' (Sola CVS series) that can regulate to ~1% are the ones to have. Other styles aren't worth getting - poor regulation and lots of inductance that can blow a timer. All ferros always draw full rated power from the wall: a 250W ferro will draw 250W even though the light bulb may only be 100W. They don't (seem) to make 100W units. Have the timer control the input to the ferro to cut down on waste heat.

They are noisy - hum like the dickens. They are also heavy, but that isn't much of a restriction in a darkroom.

Mike Wilde said:

... there is nothing in [a ferroresonant transformer] to ever go wrong, unless you over load them.

Click to expand...

Ferros are actually short circuit proof, one of their big selling points. They are inherently current limited - with a shorted output they will draw the same 250W they always do - they are sort of stubborn about that. The constant input power is a feature because it gives them good load regulation - the input voltage never sags when an load is applied - the ferro has pre-loaded the line.

As a matter of fact, when printing colour you should be able to stick with one printing time and adjust exposure only using the lens aperture. That way you minimize shifts in colour balance and risks of reciprocity failures. A voltage stabilizer would be very useful indeed.

mhv said:

As a matter of fact, when printing colour you should be able to stick with one printing time and adjust exposure only using the lens aperture. That way you minimize shifts in colour balance ...

Click to expand...

That's what the Ilford EM10 is designed to do: work with a fixed standard printing time. The Ilford meter is used for Ilfochromes where color balance is sensitive to exposure time. You spin the EM10's dial to the 'calibration #' on the back and adjust the aperature until the green light goes on.

If you are doing dodging and burning the EM10 technique doesn't work very well. The ability to dodge and burn color prints without color shift artifacts is a matter of debate. It seems if the manipulation is less than 3 stops or so then dodging and burning are practical.

The pdf file for the quick guide to the Darkroom Automation f-Stop Timer
has (hopefully) been fixed.

http://www.darkroomautomation.com/support/mfsquicks.pdf

Nicholas Lindan said:

The ability to dodge and burn color prints without color shift artifacts is a matter of debate. It seems if the manipulation is less than 3 stops or so then dodging and burning are practical.

Click to expand...

Interesting; I haven't yet printed color negs that needed either, but I'll keep that in mind.

Hi Nicholas,
Thanks for the rundown on the f-stop timer. I will take a look at the PDF file and look into it more thoroughly. Definately looks like a nice piece to have - I will keep doing B&W printing as well; I was mainly just asking about a timer for color since that seems to be where I'm headed in the near future...and I'd like to just buy one and learn it good.

Regarding voltage stabilizers - well, I'm guessing I need to buy one. The Agfa C66 (Durst M605) has one heck of a heavy transformer in the base of it that I recently seperated from the worthless timer it included. I now have that sitting to the side of the enlarger.
Would it be worth trying a few prints first to see if I need a line stabilizer, or is it just a "quaranteed - you'll need one" kind of a deal and I should try to get one before I start?

Jed

colour - control your variables

The challenge with consitent colour work is to hunt down and eliminate the variables.

Keep the paper in the freezer. Warm it up when you want to use it.

Keep the mixed up developer in glass, under nitrogen, etc blanket, if you are going to keep it around for a few weeks.

Keep the bulb putting out the same colour temperature and brightness.

Incanedescant bulbs drop something like 3% of thier light output for 1% of voltage drop. They burn out faster if pushed over voltage. I want the same light output, wether the dishwasher is on, the washing machine is running, my wife is drying her hair, or what ever else outside of the house might impact the voltage level. So for me the voltage regulation is worth it.

In the past I even kept a bulb just for colour work. Now I mostly print B&W in a more rinky dink enlarger (Omega B600) but well aligned, and with good optics. I use it over the larger diffusion enlarger with the dichroic head because it reminds me of how I started with the hobby. It also takes the MG filters, and I find swapping filters is actually easier to deal with over screwing dials in and out when I print b&w.

Jedidiah Smith said:

Regarding voltage stabilizers - well, I'm guessing I need to buy one. The Agfa C66 (Durst M605) has one heck of a heavy transformer in the base of it ... Would it be worth trying a few prints first to see if I need a line stabilizer, or is it just a "quaranteed - you'll need one" kind of a deal and I should try to get one before I start?

Click to expand...

See if that 'heck of a heavy' transformer isn't also a regulator. If it has two windings seperated by a gap with some 'stuff' jamed into the iron transformer core between the windings then it is a regulating transformer. Ditto if there is a large AC capacitor with it.


http://www.vf-transformer.com/cv.htm

Do you need one?

I'd try it without and see what happens: make one print with all the appliances on and one with them all off. The line voltage also varies with season and time of day - in Ohio there is a pronounced sag around 5:30pm in the summer when people come home from work and turn the air-conditioner on. One time it sagged to 0v and stayed there for days.

I had a Unicolor voltage unit like you appear to be describing for a number of years with no problem. Then the stepdown transformer (Omega B power supply) dried out and developed a short circuit. No problem, had purchased a spare very cheap some years earlier. Used it for a year and it did the same thing only this time it literally smoked the Unicolor unit when it went. If you do decide to go with this unit put a quick blowing fuse at the exit of the stabilizer so that a short (as I had) doesn't do it in. As per others, I now use a Sola transformer as they will take a short. Since my hearing is not what it used to be the low hum is not as noticable as it would have been 20 years ago. Have fun with color - it is both rewarding and challenging.