You are right, there is a plethora of enlarger's available at reasonable prices. There are also as many brands, sizes, negative types, etc., etc.
What combination of brand, negative type, lense and size will give the best results on an enlargement of 8 ft. by 5 ft.?
It is for my own home and as far as I know this will be a one time project.
Just thinking about the processing. Is this a wall (vertical) or floor, or can it be moved? If the first you'll need some brushes or paint rollers and trays, the second or third you may just be able to flood the surface.
If something that people are going to be moving over or past and perhaps brushing against, you may want to consider a surface protective coat like a varnish layer on an oil painting.
For that size enlargement you're going to need a very powerful enlarger lamp - at least 1000w. I'm mostly concerned about the slow slow speed of liquid light coupled with huge reciprocity failure. I would not at all be surprised if you run into exposures in excess of one hour.
An (unmodified) enlarger may not be problematic. If I used my enlarger and opened up the lens to f2.8, it would take about 4 minutes without reciprocity if I did my calculations right. Might want to consider using one of the 40mm lenses just to get your enlarger head-to-concrete distance down. The logistics are really daunting, but nothing compared to the world record photo: http://alternativephotography.com/articles/art100.html
I suppose you'd need to locate your piece of concrete and build a darkroom around it to make the exposure and process it. It would be tough to move (:
Now for the heresy.....
If I did it, I'd consider scanning the image and break it up into reasonably sized tiles. Then, print digital negatives and contact print them onto the sealed concrete tiles using the method of your choice. Alternatively, you could use the tiling method, print out laser print reversed positives and solvent transfer the image onto the concrete. I've never tried that, but it sounds plausible.
There are lenses particularly designed for mural printing, like the Rodagon G, but whether you need that will depend on how smooth and even the surface is. If you're going to polish the surface and can get it pretty flat, then it could be worth buying the best lens you can get and selling it afterward. If it's going to be relatively rough (compared to glossy FB paper), then the surface itself will limit resolution, and any decent 6-element enlarging lens should do.
Ian Grant has done things like this on vehicles, so he might have some ideas for you.
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Yes David's right I spent 10 years putting images on to a variety of surfaces, predominantly vehicles or painted metal sheets.
I never tried concrete but it wouldn't be any different to wood, where the problems are the porosity of the material used. I would suggest sealing the surface with a clear-coat lacquer, we always used a 3 pack from Glasurit. This would need to soak well into the concrete, and two or 3 coats given to ensure it's well sealed, then left to dry fully for a few days- as long as possible. Before coating with photo-emulsion you would need to prepare the surface with 600 grit Wet & Dry paper to give the surface a key for the emulsion.
The emulsion will have to be sprayed to coat an 8ft x 5ft surface, this takes a bit of skill getting the right consistency etc to coat evenly, and ensuring it sets as you spray. We made our own emulsion, and also trialled Ilospeed Gd3 emulsion for a short spell. Our enlarger was a modified De Vere 54a mounted in a cradle, we custom built a condenser light source with a 275W bulb and typical exposures were around the 2-3 minute mark for an 8ft long image using a 150mm f5.6 Vivitar VHE lens (actually a Componon) at f11-f16. Your negative needs to be slightly higher contrast/gamma for these sizes.
We didn't dry the emulsion before exposure/processing, but we added extra hardeners etc to the emulsion & the developer, the alternative is to let the emulsion dry overnight, usually takes around 12 hours to air dry. Again you will need to spray the dev, stop & fix, garden sprays are ideal. Developer will need to be modified, we always used Ilford PQ Universal or May & Baker (Champion) Suprol, at 1+19 dilution (instead of 1+9) with additional Sodium Sulphite and hardener. The sulphite helps prevent aerial oxidation as the emulsion isn't totally immersed in developer, and using the dev more dilute makes it far easier to get even development. We fixed with Hypam again more dilute than normal. We washed for 3 hours, but an hour is sufficient if the emulsion was dried prior to processing. We used a washing rig made up using crop spraying parts from an agricultural supplier.
You will have to ensure that no chemicals or water are allowed to soak into the rest of the concrete and there will be a considerable volume of liquids to drain away. When the image is finally washed and dried then you will need to coat it again with the Clear-coat lacquer.
All spraying of lacquers, emulsion etc should be carried out with airline respirators, googles etc, and you will need fume extraction. Processing can be done with a respirator.
It's a far more daunting prospect than it initially appears.
Thank you everybody. Everyone has been very gracious and very forthcoming with information.
I have the equipment for the actual installation of the piece. The piece will probably be laying flat so i can build a frame one the edges and use a chalk of some kind to seal it, then I can flood the surface if need be.
I already have the diamond polishing pads to polish the surface to a 1000 grit shine. I have done this before with counter tops and other custom installations.
I believe I will use 2 coats of a deep penetrating concrete sealer then a coat of clear lacquer. The concrete sealer is made to neutralize the Ph in the concrete. That should stop the surface salt crystallization that sometimes happens under surface applied coatings.
Enclosing the piece to create a darkroom environment, also, is not a problem. My studio is 1200 sq ft. with 10 ft ceilings.
That leaves the enlarging process itself.
Several people have commented on the long exposure times for Liquid Lite. Are there any other considerations? Time is something I have plenty of.
As I said before, this will probably be a one time project and I have not developed an eye to appreciate the fine tuning of a photo, as I am sure many of the people on this forum have.
That said, I am looking at a couple of pieces of equipment on Ebay.
Schneider-Kreuznach Componon 150mm 1:5,6 Enlarging Lens
bogan x358 black and white photo enlarger
Beseler 23C Enlarger with dichro 23 dga colorhead
Will the lens work with either of the enlargers?
Have a background in fabrication, building a cradle for the enlarger shouldn't be a problem if someone can explain a way to determine the distance the enlarger needs to be from the surface.
What is the size of the negative?
A beseler 23C enlarger is designed for negs up to 6x9 cm. A 150mm lens is for enlarging 4x5" negs. You could use it with smaller negs, but then you'll need more distance between the enlarging head and the print surface, which isn't what you want if you're making a very large print.
What lens should I be looking for to go with the Beseler?
It depends on the size of the negative. What is the size of the negative?