Exploring options for adding ND to my light path

Hey all--

I'm currently making my prints using a B22 I picked up for a song on Craigslist. I shoot a lot of stereo pairs, especially in 35mm, and generally I like to print them small to create an intimate viewing experience as well as minimizing eyestrain. Most of them get printed at 3.5x5.

Even with my 80mm EL Nikkor and 75W bulb, this print size tends to create very short exposure times on the paper. I've noticed when I go below about 10 seconds at a bare minimum, the pairs almost always come out with visible tone differences due to the relative inconsistency between two 4-second exposures (compared to, say, two 20-second exposures). I am using a timer for my enlarger, so this isn't just human error with a metronome.

After doing a lot of research, I've concluded the best way for me to get longer exposure times for consistency's sake (and for other project where I want to have a lot of time for careful dodging and burning) is to use some kind of neutral density in my filter drawer.

I have two options here: stack multiple contrast filters, or get some ND gel like this stuff from B&H:

https://www.bhphotovideo.com/c/product/163139-REG/Rosco_102302092124_E_Colour_209_3_Neutral.html

Has anyone used that stuff in a filter tray for their enlarger before? The simplicity of adding one layer per stop of additional desired exposure time is compelling. However, if I can achieve the same result using my contrast filters, that seems like a good alternative as well.

So I guess my question is, if I stack a Grade 1 filter and a Grade 3 filter, the contrast should come out identical to just using a single Grade 2 filter, right? And similarly, using a grade 1, 2, 4, and 5 filter all at once would balance out to the same print contrast as a single Grade 3? Please let me know if averaging the grades is not the correct way to anticipate contrast.

Try a lower wattage bulb.

I considered this, but I'm having trouble finding one under 75W that is a good match for my lamphouse without causing additional complications (different color temperature, etc. etc). Do you have a source?

BHuij said:

So I guess my question is, if I stack a Grade 1 filter and a Grade 3 filter, the contrast should come out identical to just using a single Grade 2 filter, right?

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I don't think so. The filters filter out light, they don't add light of a complementary colour.

If you stack multiple sets of #2 filters, you may get what you need.

BHuij said:

I considered this, but I'm having trouble finding one under 75W that is a good match for my lamphouse without causing additional complications (different color temperature, etc. etc). Do you have a source?

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Well, "75 watt" doesn't tell us much, other than it consumes 75 watts of energy. We'd need to know more about what you have in there.

I too have a B-22 with normal 75 watt bulb PH111. Consider a rheostat or dimmer switch, found in most hardware stores, to reduce the intensity. I usually reduce intensity by half. It works for me very well in my tempory bathroom setup and its not complicated either. This for B&W work with Ilford RC paper.

It's a regular 75W incandescent bulb made specifically for enlargers (in fact I think it's the stock bulb that came with this thing, the previous owner doesn't seem to have used it really hardly at all, so it's probably the 75W incandescent made specifically for the B22).

I've looked into the rheostat or dimmer switch options, but apparently dimming your bulb changes its color temperature, thereby screwing with your contrast.

Stacking the filters will give longer exposure times. The grade will be some intermediate grade but may not be the mean value. Each filter already has some effective neutral density (assuming no red sensitivity in the paper) to make the printing times equal between filters. But each filter has a different combination of Magenta and Yellow filtration. A #5 ( perhaps equal to M150) stacked with a #00 (perhaps equal to Y150) could appear to the paper as only neutral density. Blocking nearly all exposure. You should experiment if you have the filters already.

The Rosco filter, however, would be the way to go.

480sparky said:

Try a lower wattage bulb.

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The B-22 uses an odd little bayonet bulb. You could also buy a sheet of Rosco ND "gel" and cut a piece or two for the filter drawer. Rheostats to lower illumination also change color temp of the lamp and will affect the contrast when printing VC paper.

What f/stop are you using? The obvious question is have you stopped down?

Yeah, I am already at the smallest aperture. Not only is it not getting me long enough times still, but I also want to use the lens closer to its sweet spot.

Think I'm going to go with the ND gels. Thanks all for your advice!

If using a rheostat to reduce intensity causes a reduction in contrast is true, then use contrast filters to correct it. Thats what they are for. To me, this simpler than messing with neutral density filters. Just my 2 cents.

I'd recommend an ND filter.

Very often I will put an 0.6 ND filter in my enlarger to keep printing times reasonably long.

If I had it to do again, I'd do a little calculation and pick the density of my ND filter to aim for a 32 second printing time at the enlarging lens' optimum aperture for my intended print size.

I get tired of using f/22

BHuij said:

I considered this, but I'm having trouble finding one under 75W that is a good match for my lamphouse without causing additional complications (different color temperature, etc. etc). Do you have a source?

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There were indeed 50W (55W) enlarger bulbs. You could use an opalized household one instead. But at least over here finding such locally seems more tricky than to find an opalized enlarger bulb. But even then you would have to recalibrate your system.

So I guess my question is, if I stack a Grade 1 filter and a Grade 3 filter, the contrast should come out identical to just using a single Grade 2 filter, right? And similarly, using a grade 1, 2, 4, and 5 filter all at once would balance out to the same print contrast as a single Grade 3? Please let me know if averaging the grades is not the correct way to anticipate contrast.

No this is not true... Use ND filters as suggested.

I would at least look for a useable lower wattage bulb. If you end up using a dark nd filter like a 3.0, if will probably have to be removed to focus and then reinstalled.

Get the Rosco ND gels. I know two people who do this regularly with Beserler 23C enlargers that take the same little bulb.

Check FreeStyle for lower wattage lamps. If they are available, it will be easier than using ND filters.

If there is a stage and display supplier in your area, get neutral density film, cut it to size and lay on top of lens. The sheets are usually 12" squares, and are under $10 each. If one gets scratched, just cut another piece. Is is available from one stop to 10 stops density.

You can also use a screw in ND filter onto the front of the lens.
The light reduction would be similar to using a lower wattage bulb, so you can just leave it on. Granted it is usually easier to focus with max brightness.

ac12 said:

You can also use a screw in ND filter onto the front of the lens.
The light reduction would be similar to using a lower wattage bulb, so you can just leave it on. Granted it is usually easier to focus with max brightness.

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That is what I would do. That way the light is bright enough to focus either by eye or by grain focuser [enlarger, microscope].

I keep a glass ND filter around specifically for this purpose. In my case a two stop is just right, but it seems the OP could use more than two. I wouldn't mess around with the gels. They fade and get scratched easily. Glass ND filters can be picked up for cheap on ebay since no one uses the 1/2/3 stop filters anymore. You can either get the appropriate size to screw on the front of the lens, or get a bigger size and just lay it on top of the lens. I prefer the second route since I put the ND filter over multiple lenses.

You could wire the enlarger in series to another light bulb outside the darkroom. This would reduce the voltage to the bulb.

You could even make a contraption that allows you to switch back to normal brightness for focusing.

In such case an off the shelf in-line dimmer would be the more practical way to go.

(But if the enlarger does not contain a mains-run lamp, but a low-voltage one, trouble may already start depending on model of dimmer.)

An inline dimmer would cause problems with the voltage control.