Hi, Does anyone know a way to diffuse the light on a condenser enlager to reduce grain? I have a small Omega C700 tungsteen head condenser enlarger. My prints are very sharp, but grainy too. Even when using B&W ISO 100 or 50 films the grain is apparent at 8x10 enlargements. However with ISO100 color film the grain is more subtle. Anyway, I was reading The Print from Ansel Adams and he mentions the placement of some sort of white glass/plastic on the filter drawer in order to diffuse and soften the light approximating the effect of a diffuser enlarger. Can anybody advice on that? Thanks, Herbet.

-- Herbet Camerino (herbetb@yahoo.com), January 29, 2001

Answers

Herbert, I think what you want is opal glass. Omega usually has them. Check you local photo (pro) store to see if they can order one. You can get by with a piece of translum or a frosted filter used to diffuse strobes/hot lights. Cheers

-- Scott Walton (f64sw@hotmail.com), January 29, 2001.

First, bear in mind that grain increases with negative density, so make sure you're using the minimum development time you need to get good shadow density. I had a C700 and did not experience what I would call excessive graininess.

Second, I tried what you're talking about and found that exposure times increased exponentially. I never did get a good comparison print because I was unwilling to expose for the 2:00 to 3:00 minutes that would have been required.

Third, the answer for me was a new enlarger with a good diffusion colorhead. Times are good, spotting is down, and contrast is great.

-- Brian Hinther (BrianH@sd314.k12.id.us), January 29, 2001.

If the lamp in the enlarger is an opal bulb type, then what you've got is a semi-diffused system anyway. Only a point source (small, bare filament bulb) will give you the true condenser effect.
The place for any further diffusion is above the condensers. A piece of ground glass is ideal, or you can buy fire-resistant spun diffuser material of the sort that's used for theatre lighting. If this works OK, then painting the inside of the lamphouse white, or lining it with kitchen foil, will increase both the diffusion and the efficiency of the light source.

I'd agree with the above post that if the grain from 100 ISO material is objectionable in a 10x8 print, then there's something wrong with your processing, or the film you're using is stale.

-- Pete Andrews (p.l.andrews@bham.ac.uk), January 30, 2001.

How does this opal light look like? The camera store people seem to have never heard of something like that and the only place I found on the Internet is BH photo. However, there's no ilustrative picture and it's available only in 220v. The bulb in my enlarger is small and white. How do I now if it's opal? Thanks, Herbet.

-- herbet (herbetb@yahoo.com), January 30, 2001.

The depth of ignorance of camera store salespeople never ceases to amaze me.
The milk white translucent finish given to glass is called opal, or sometimes 'flashed opal'. If your bulb is white, it's an opal bulb.

-- Pete Andrews (p.l.andrews@bham.ac.uk), January 30, 2001.

Brians post dealt with making sure that the development was correct and stated that would help the shadow density. I am sure he meant to say, highlight denisty. Development controls the highlights and camera exosure controls the shadow density.

-- Lee Carmichael (click@flash.net), January 30, 2001.

Conc. the Opal lamp for an enlarger: There must not be any lettering on the bulb, and the frosting is a bit denser than that commonly used for residential lighting.

Pete Andrews wrote: "The place for any further diffusion is above the condensers."

I doubt that. It also works fine if you insert a diffusor below the condensor, such as in the filter compartment.

Regards, Thomas Wollstein (thomas_wollstein@web.de)

-- Thomas Wollstein (thomas_wollstein@web.de), January 31, 2001.

The reason for recommending diffusion above the condensers is that it makes more efficient use of the light available. It also allows a slight texture in the diffusing material, which might print through if it was next to the negative. Above, below, or in between the condenser system has much the same diffusing effect, but the brightness of the light varies.

-- Pete Andrews (p.l.andrews@bham.ac.uk), January 31, 2001.

I used an old piece of ground glass cut to a size that would fit in the filter drawer of my Durst M600. It was really very handy as you could remove or replace it depending on the effect you wanted. (Faster than lamphouse modification)There was a slight change in exposure time but it would soften the grain without seriously affecting overall sharpness. As I am now using a Beseler 23c, I'm going to have to find a much larger piece of ground glass.

-- Karl Price (karlmikl@centurytel.net), February 02, 2001.

You can make a ground glass diffuser by having a piece of glass cut to the size you need. Then go to a shop that sells supplies for machinists and get some 600 grit carbarundum (sp?) powder. It is an abrasive powder. You put a little oil on the glass then sprinkle a little on. Take a paper towel and abrade the surface with this abrasive slurry.Wash it up, and you have a diffuser to put wherever you think apropriate.

-- Bruce Appel (appelgate@aol.com.), February 09, 2001.

So what’s the bottom line? Can we soften the light on a condenser enlarger to the point where an experienced photographer couldn't tell the difference between a cold light print and a condenser print? I have a Beseler 45MCRX and I would like to avoid the expense of buying a cold head especially if I can successfully modify the one I have. What I don't want is half-assed results. Thanks, JC

-- Joe Corra (vsmi@aol.com), February 12, 2001.