The color head should have dial for Cyan filter. You might try Cyan as an ND filter. I've heard it works, never tried it myself.
You don't say what size print your trying to make. Little prints will mean fast times.
I would be careful in the placement of a ND gel. Things get HOT in there, and melting/ burning, etc., can cause an awful mess.
What enlarging lens are you using? Most - Rodenstock, Schneider, probably Nikon, and others, will accept screw-in filters; and ND glass filters, all the way to X10 are readily available, and relatively inexpensive.
As for the "sweet spot" ... usually the "optimum" aperture will be in the center of the aperture range. However this is only a design "target" ... many other criteria are included in the design of any lens. The apertures are there for a reason ... and *NO* enlarging lens, other than some coke-bottle jury rig, is going to be noticeably worse at either the extreme of the aperture scale. I am more of a "fussy perfectionist" than most, but using all of the apertures possible in an enlarging lens is something I do not worry about.
Ed Sukach, FFP.
You know, if this thing is really way the heck too bright and you're mainly interested in small prints, you may be able to print on Azo with it.
THANK YOU ALL I think I'm getting the picture
Thank you all for helping me thing through this...what a great forum, and taking the time to help a new forum member is great!
A few you you have asked questions I will answer:
The enlarging lens is a Rodenstock Rodagon N APO 80mm.
The prints are 9 inch square (from 2 and a quarter negs).
[COLOR=Blue]After having read all you have said, my solution is this: I will purchase the best screw in, below the lens ND glass I can acquire, I would imagine that
B + W or Leica or Nikon glass is the best. I will also not worry too much about stopping down all the way, i.e. f.22 on this lens, if need be. Probably, alignment is more critical than stopping down to the minimal aperture.[/COLOR]
Unless anyone has any other ideas, this is my plan. By the way, my website for my photography is www.grenellphoto.com
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I agree with Joe and others , Put a nd filter into the mixing box.
As well I like my apeture to be 2 fstops from wide open with a 10 - 15 second exposure with glass carriers. that is the sweet spot that I have found for the work I do.
I am not familiar with this enlarger or light source. From the link it looks like a quality enlarger. But all of the "rigging" to turn it into an enlarger with normal exposure range doesn't make sense to me. Something has to be wrong. You shouldn't have to stop it down to f22, add neutral density filters,devices to reduce electricity or use special slow paper just to achieve what I get with my cheepo Saunders/LPL D7600 enlarger. With a 6X6 negative, 80mm lens, dialed in filtration of 3 contrast and enlargement of that size I get a 12 second exposure at f 8 or 11 depending on the negative.
"When elephants fight it is the grass that suffers"
IRAQNAM is Bush's legacy
[QUOTE=Bob F.]Unfortunately, dimming a halogen lamp will drastically reduce its life - it really needs to run at full temperature to work correctly.
Yikes - I was not aware of this. Is this also true of the typical halogen desklamps/pedestal lamps that come with halogen bulbs and built-in dimmer switches? Or are we talking about a whole 'nother animal?
Dimming halogen lamps
the mechanism that makes a halogen lamp useful is that the filament surface is supposed to reach a boiling temperature. the halogen, usually iodine, that is added to the filament in controlled amounts is supposed to allow some of the metallic filament molecules fill the valcuum in the bulb and condense or sublimate back on the cooler ends of the filament to start this cycle over again. if you have ever replaced a halogen bulb in a flashlight that was dark or silvery in appearance that is exactly what has gone wrong, using a halogen flashlight with low batteries is the fastest way to kill a bulb i know of. the entire envelope that contains the filament must be hot enough to keep the vaporized filament molecules as a vapor. the sublimation happens at cool spots and if the glass is cool enough then the molecules will condense there rather than where they have the strongest affinity to condense on the cooler ends of the filament.
common incandescent bulbs do not suffer this fate as they do not operate at such high temperatures to start with. putting a dimmer on a halogen bulb can be an effective way to control light output in the top third or so of it's peak output, but much lower than that will make this halogen cycle fail, the bulb will grow darker and it will fail as the filiment boils away. if you need less light, the preferred method is to use a lower wattage bulb rather than use a dimmer.
the standard bulb that fits this enlarger is an ANSI standard ELC bulb, the only thing i can find that comes close in a lower wattage is the EJL bulb that is 200 watts. how long this will last is another story since your fujimoto enlarger has a ballast that feeds the HID (high intensity discharge) ELC bulb. sounds like you need to concentrate on the ND filter option rather than risk voiding the warranty or frying the power supply/balast of your enlarger. or revert to something old and simple like an omega D2v that uses a low tech 75 watt opal lamp.
another thing to investigate is simply calling the importer of Fujimoto enlargers and ask them is there is a lower powered bulb recommended for your enlarger. that might border on blasphemy sort of like reading the manual, but it's worth a try.
sorry to be the bearer of bad news.
Originally Posted by Bob F.
What paladin said ...
I was aware of the halogen cycle, but only in very general terms: thanks for the detailed explanation!