ND filter in enlarger

Hallo,

Odd question this but I have a 6x6 condenser enlarger that I have used since new for 35mm negs and got used to how it performs with my negs using the 35mm neg holder and Nikon 50mm f4 lens.

Recently I have started shooting 6x6. Now using this enlarger with the 6x6 neg holder and a Rodenstock 80mm f4 lens the printing times are much much shorter than I am used to.

I guess that this must be expected as all the light is now able to be passed through the neg whilst before some of the light did not pass through the smaller 35mm neg.

If I was to put a neutral density filter in the light path to increase printing times, anything to watch out for? Should it be above the neg, below the lens, does it matter? Using multigrade so not relly wanting a clour shift from a cheap ND filter but want some time to possibly dodge the print!

Thoughts?

Sim2.

You can put an ND filter in the filter drawer, if you have one or mount a clean ND filter on the lens. If you don't have a filter drawer, you can put an ND lighting gel between the bulb and the condenser lenses.

If you have a Beseler, here's one way to do it...

Thats a Cokin 153 (4X filter factor) in a drop-in tray that slides in just above the lens.

Simple and effective...

Reinhold

www.classicBWphoto
if that doesn't work, try: http://mysite.verizon.net/res14rg7y/

Holy Kow, I didn't realize that I attached a tabloid size photo!

Sorry...

Reinhold

Use a lower wattage bulb. Every layer in the optical path is a dust magnet. Also, are your negs of similar overall density? Printing times really should be be within a stop or two when changing formats. Also, check to see that the lamp head is in the right location -- on a Besler 4x5 you have to move the lamp head up and down to match the format -- that may or may not be true of your enlarger.

The easiest thing to do is to screw in an ND filter (1, 2, or 3 stops depending on your needs) below the lens. If you have multiple lenses, find the largest diameter and get step-up rings for the smaller lensed. That way, if needed, you can use a single ND filter on any lens that you have.

I picked up some Heliopan ND filters and they work fine on my 4x5 enlarger. Most enlarging lenses for 35mm and medium format have relatively small diameters so even the best filters are still reasonably priced.

I use Rosco cinegels to accomplish just what you need to do. They're cheap at $6.50 for a 20 x 24 inch sheet, and are available in full and 1/2 stop densities. Cut 'em down and stack them in the filter drawer. There's no color shift and they can handle the heat just fine. Works like a charm. See here: http://www.rosco.com/us/filters/cinegel.asp

Another vote for Cinegels, though the idea of a lower wattage bulb has a lot to recommend it.

Using a lower wattage bulb sounds OK in theory but, depending on which enlarger you're using, you might get increased light fall-off. This happened with my Durst AC707 condenser head. The 75w bulb is physically smaller than the standard 150w and produces a smaller 'footprint'. I'd go with the ND filter. I've used graduated NDs in the past with pretty good results.

Whatever you do, make certain that you can change light output easily and quickly.
You don't really want to take the lamphouse off to change a light bulb for that extra dense (or thin) negative do you?
Forget about a dimmer- that changes the light color- messes up VC paper contrast response/

Jerold's solution is a good one, even if it's a bit $$. I don't know if Rosco gels are OK below the lens, but Cokin and similar resin filter are definitely ok below the lens. It's easy to devise a simple holder like the old Kodak Polycontrast filter to hold a resin filter (Ambico, Calumet, etc.), letting you swap light output in a couple of seconds...

Reinhold

www.classicBWphoto.com
if that doesn't work try; http://mysite.verizon.net/res14rg7y/

Another option is if you use Lee filters. You can buy an adapter ring for your enlarging lens so you can use the Lee filter holder and then use Lee ND filters or get the snap together gel filter holders so that you can slide gels into the filter holder. Pricey if you don't already have the system.

Hallo,

Many thanks for all the replies.

The enlarger has a fixed condenser set so this cannot (unfortunately) be moved to "focus" the light at the neg plane. Using it for 35mm involves using neg plates that physically block the light from around the neg, so effectively only around 1/4 of the light from the bulb/condenser goes through the neg. With the 6x6 neg plate all the light from the bulb/condenser goes through the neg.

It is that I had got used to the printing times for 35mm negs that the much shorter times for 6x6 took me by surprise.

Solutions to increasing the printing time; I think that I prefer the ND filter - have to see what is available to fit the filter drawer. Although I have the Lee system I do not think this will fit under the lens, I use the multigrade under lens filter holder and that is a tight squeeze as the focussing rack is close to and extends below the end of the lens plane. Was concerned about colour shift affecting the contrast responses of the MG paper so will have to be a quality ND filter and for this reason I think the lower wattage bulb, although the most elegant and inexpensive solution, is one that might cause more issues than it solves.

Anyway, thanks for making me seriously think about this rather than just grumbling to myself! :rolleyes:

Sim2