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we are currently building a 8 x 15 large format enlarger, we need a light source that works and has fast action on the switch power up procedure, i have viewed phil McCourts information, but i am looking mr-16 or anything new???? any thoughts and what type of air do we need to cool the unit ie fans blowers etc.
we are looking for any process photos of the construction or just dont's and do's.
thanks
For that size negative, first of all I would bulld it to enlarge 8X20 negatives because that is a much more common format and it would allow enlargement of 7X17 format as well. I am assuming here that you are thinking of a black and white enlarger...so here goes.
To save engineering considerations involved with incorporating dichroic filtration, since condensers would be difficult and costly to formulate and produce, I would opt for a design to allow above lens contrast filtration. I would look toward one of two light sources. The first would be four each of 1000 watt halogen lamps feeding each corner of a diffusion box with an 8X20 frosted (diffusion) acrylic panel on the bottom side. This will require a cooling fan capable of moving at least 450 CFM to cool the diffusion box. Each of the lamps will need to be filtered or in lieu of that you could use Rosco filter material as a single color filtration below the diffuse acrylic panel on the bottom of the diffusion box. The use of green and blue would allow you to split filter print.
The second design would use a bank of flourescent light tubes. This solves some problems of the other design but brings other problems to bear. Generally speaking, I would opt for the first choice because of the relatively lower light output of the flourescent lamps which may lead to inordinantly long print exposures.
The design of the diffusion box would need to be that the light path of each lamp must be reflected off at least two surfaces to gain even light distribution across the 160 square in negative area. The use of a whilte ceramic interior of the diffusion box would deal with heat and if of a rough surface will provide for greater light diffusion.
The use of both types of light may require the incorporation of a shutter on the lens to provide for more precise initiation and termination of the lamps output. A Packard shutter modified to use an electrical solonoid as the actuating mechanism would be a quick and easy fix. I would opt for 24 V on all control circuitry. If the first (4000 Watt lamps) are chosen than I would opt for 220 Volt since it would require a 20 amp branch circuit whereas at 115 volt it would require a 40 amp circuit. (# 12 conductors vs #8 conductors).
This will give you reasonable printing times and a design that will work.
Dear jimmygcreative,
Here's an interesting approach: http://www.textklick.demon.co.uk/leden.htm.
Neal Wydra
The LED enlarger idea is cool. As the LEDS are quite efficient, you could probably run it off batteries... Or solar power if you live in a sunny place. At least when doing smaller formats. :)
thanks for the help on this! great ideas so far!!!!!!!!! we might just go a bit bigger now11 x 20.
can anyone out in the group find any shots of home built enlargers in working spaces and post them?
thanks jimmy
This thread is a good starter, if you haven't seen it yet: http://www.largeformatphotography.in...ad.php?t=19820
Can't you just be happy with contact prints?
Okay, okay. I don't know what it is you mean by 'fast action'.
DM's idea of halogen isn't bad. I might use a bank of 20W or 50W halogens instead of the big whoppers. You could make it like Ansel's horizonal enlarger. Put them on tracks. Lots of heat. I don't imagine you will be enlarging by a big factor, so it would seem like you would not need tons of light. As an example, I think a 45 condenser enlarger uses 150 to 200W of tungsten to cover 20 sq in of film. This is an okay amount in tungsten for modest enlargements. My 1212 V54 tube is about 200W and covers 100 sq in of film and is fast. For 6x7 is it okay and for 35mm it is a bit slow. Of course for 35mm, the enlargement ratio is higher. Figure this in.
Be sure to do as Donald says about sizing this thing. 8x15 is not too common. You should go up to some 'normal' aspect ratio above what you have and then oversize a bit. Remember that the lens will 'see' beyond the diffusor a bit as diffusors are not perfect. Oversizing will give you more even light. Given all of this, if you decide to sell or rent it out, there will be a market.
If I were to do this, I would go with a cold cathode grid, such as Aristo V54. This wouldn't be cheap, but unless your time is free and your materials cheap, any other approach will bog you down and cost more. LEDs are out. Nice idea and maybe okay for small negs, but not here. Read other threads on this topic here and at APUG. LEDs have been around a long time and they haven't flooded the market. What does that tell you? And you will never get high contrast.
Given some form of coldlight and such large negs, you will have to use a glass carrier. Read the newton ring threads that have been so prevalant lately. Then make your carrier with clear glass on the bottom and the diffusor on the top---no other diffusor above. This is newton-ring-proof.
Now back to guessing what fast action means. If this is lamp startup worries, then the closed loop timer, whether Metrolux or RL, etc., will compensate for this. If you are projecting onto something fast and need short exposures, then you will need a shutter. Coldlight, halogen, everything has startup and decay issues. Compensating timers account for startup issues, Metrolux even figures the decay into the exposure.
Whatever you do, go with the most used, most known technology, and one that you are familiar with. This will make life so much easier when you run into problems. If you do something too weird, there will be nobody to answer your questions. Good luck.
-EW-
I have built 3 very large format enlargers when I had a photo business. My first one used 5 24" flourescent tubes and had the same exposure times as the previous owners homebuilt which used 6 500w photofloods as a source. Light output colour is not ideal for vc paper and if I were doing it for that paper, I would build a bank of low wattage quartz halogen lamps. A box with a fan and air filter connected with flexible hose would keep it cool.
contact prints are great I love them, and the best photographic work I ever viewed in person was a med format 6x9 contact print series printed around 1949.
okay , wow sounds like we will go with the low voltage system. we will go with the 600-1000 watt system, do you think thats over kill? what do you think the target wattage should be for vc max filter?
also, the bellows that we have is for a 8 x 16 camera so its smaller than the 11 x 20 target enlarger size. could we just add a hard bellows made out of wood the keeps the angle or should we make a new one out of fabric, it would be similar to a wide angle bellows.
any ideas???
thanks!
JG
What lens are you planning to use? Are you planning a vertical or horizontal design?
the enlarger wil be a vertical unit.
we will be using a brass lens anastigmat 16.25 inch welling camera works lens and a process lens around 300-600mm not purchased as of now.
thanks
JG
Make a bellows extension out of wood. That is the easiest solution. I made extensions for one of my frankenlargers which gave me 48" of extra bellows. I never had any problems and I was doing enlargements with very tight exposure tolerances.
I’m just thinking aloud here, and I may have my formulas mixed up, but…... I am not familiar with the lens you mention, but a 16.25-inch lens would need 70-degree coverage for the 11x20 neg, and I’m guessing a lens of that coverage would have problems with edge definition in enlarging. A process lens would probably work better, but with its smaller angle of coverage it would need to be around 600mm. A 600mm lens of a vertical enlarger will need more than the average 8-foot ceiling, unless you print on the floor and have a very thin light source. I would consider a horizontal design for such a large negative.Quote:
Originally Posted by jimmygcreative
You could use prism/mirror attachments from graphic art cameras to convert vertical into horizontal projection for bigger images.A front surface mirror will also works.
If I am going to put my 8X10 enlarger back into operation,I am thinking of using studio flash as the light source because of the heat problems from quartz lamps.
First post here, although I've been lurking for a while.
Firstly, thanks to all those who have contributed to this thread. The discussion has been very helpful as I'm thinking about building an 8x10 enlarger sometime in 2007, and have a some "getting started" points or questions:
1) Not yet decided whether I want to go for a vertical or horizontal design. Any pointers? I suppose I could figure out the distance between the film plane and paper needed given for the enlargement factor, which might favour a horizontal design.
2) Light source: Considering two 500W 230V (I'm in the UK) halogens with some kind of reflector, I think Donald Miller suggested white ceramic earlier in the thread.
3) Cooling: The fan in the case. This obviously needs to be light tight. Presumably ducting could be used to extract the air into a light trapping device either internal or external.
Tom.
For the fluorescent option which i think may be your easiest, check out http://www.kinoflo.com. They make a few new fixtures that use biax tubes which are much brighter than any standard flourescent and available in 2900K or 5600K. The Parabeam and the Diva Light are very expensive units but you can get alternative ballasts from an industrial supply store.
something that you might want to put into serious consideration is going the Ansel route... that is to find an old junked wooden camera chassis with a half decent bellows and turn it into a horizontal enlarger. Or if you're really brave, a vertical enlarger. Here look at this:
http://cgi.ebay.ca/ws/eBayISAPI.dll?...5978&rd=1&rd=1
You could make a 14x14 enlarger!... uh.. right... Of course you'd have to pay 29384872373943827493287 dollars for freight, and there's the matter of how to hook it up with lamps, but that's life I guess....
I agree with VINNY. The fluorescent option would produce much less heat and most likely give more even light. Aristo makes the T-12 unit for 8x10.
Hello and Happy Holidays to All,
I showed my plans to an electrical contractor and he said I should go with outdoor low voltage 50 watt landscaping fixtures. The question would be what amount of wattage would we need to make a 42"-50" x (neg aspect) fiber based print from a 8 x 10 neg. keeping in mind 2-3 min. exposure time, with max contrast filters used.
Our guess for the wattage formula would be around 500-600 watts- Xenon MR16 dichroic halogen reflector will be our lamps.
thanks!
Jimmygcreative, how did the enlarger project go? Did you finish it and what route did you take in its construction?
Does anyone know if Jimmygcreative is OK?
I am doing great thanks! as for the enlarger my electrical tech is working on the transformers for the unit, hes doing the design during his free time and hes busy running his electrical company. we are finished with the bottom end now, and the system for the rigging will be s40 speed rail. with movable from vert to horz.
thanks for asking
jimmyg
Sounds like progress. Got pix?
jimmyg, I have several Durst tranformers, all new in various sizes and volts. Email me with what you need, I may have one cheap.
Well the new darkroom is finished so now I have time to spend on the 8 x 15 enlarger. Heres the mock -up, we are working on new ideas from this so I will be asking tons of question later this month (I hope)
thanks
We will not be building the enlarger, better news to report .....Just Installed a mint Durst cls 1840 with all 35-8x10 items in my darkroom and I am so happy! Can't wait to start printing.
photos of the durst 8x10 installed and other darkroom pics.
http://www.jimmygcreative.com/assets.../darkroom1.jpg
http://www.jimmygcreative.com/assets.../darkroom3.jpg
http://www.jimmygcreative.com/assets.../darkroom2.jpg
You're a lucky man with both the space and enlarger *drool*
rob -
how on earth did you manage to register as 'rob' after me and without having being forced to add on some number to your name?
(Sorry - this is off-topic!)
Strange, can it be the lowercase r?Quote:
Originally Posted by Rob_5419
Quote:
Originally Posted by jimmygcreative
it looks ridiculously small :D
One other option for others to consider.
A graphic arts vertical camera, using 24" HO flourescent bulbs for a light source, say 4" O.C., 5" from a 3/16" white acrylic diffusor.
Pluses:
- A vertical camera is an enlarger in reverse, not to mention you will probably get a decent lens in the process. (pun intended)
- Vertical cameras are cheap, from free to maybe $100 or so
- If you're lucky, you'll get a vacuum back too, with 4 feet attached to the back, it's a ready to go vacuum easel.
- Did I mention cheap, durable and over-engineered?
Minuses:
- Heavy
- You'll have to get a little creative
- It won't go up to the ceiling and enlargement is somewhat limited
erie