Short Exposure Times when printing medium format - is this normal?

spencewine · Dec 15, 2011

This is my first time printing with medium format negatives, I've only printed 35mm up to this point. So I was printing an 6X6 negative at an 8 inch square an I noticed that my exposure times were really short even when I stopped the lens down to f11 (as compared to what I was use to printing with a 35mm at F5.6). My exposure time was about 3 seconds and my negative looks good (not thin). With that exposure time I have very little time to do much dodging. The enlarger I am now using for medium format is an Omega D2 w/ 80mm lens. I use a Leica V35 to print 35mm (so I don't have an option to test the medium format on the other enlarger and I don't have a 35mm negative carrier for the D2). I'm wondering if it's the fact that I'm enlarging the negative much less compared to the 35mm (at 8X10) that is causing the very short exposure time or if it's something else. Any ideas of what could be going on here?

martyryan · Dec 15, 2011

I have a DII and changed out the 250watt bulb for a 150 to lengthen times and will use f16 as well, otherwise my times were very short like yours.

Konical · Dec 15, 2011

Good Afternoon, Spencewine,

Print exposure times for a given sized print are normally shorter with bigger negatives. Three seconds at 11 seems a bit short, especially if you have any VC filters in place, but it's really hard to judge without seeing the negative and knowing how efficiently your enlarger produces light. Paper speeds also vary and you don't mention the kind you're using. There are too many unknowns here to give a definitive diagnosis.

Konical

chassis · Dec 15, 2011

I experienced too short (for me) exposure times when I was printing 6x7 negatives with a Beseler 23XLII. Can't remember what bulb wattage I was using, but my solution was to add a neutral density filter to the filter drawer, in combination with variable contrast filters. It worked for me.

Now I am printing 4x5 with a Beseler 45VXL and a 250 watt bulb. Exposure times are admittedly short, but in the acceptable range for me. If I start doing much dodging or burning (I do straight prints only right now), I see a need to lengthen exposure. I would do this with either a lower wattage bulb, or by adding neutral density filtration.

DWThomas · Dec 15, 2011

I had a similar experience with my Omega B8 and resolved it by picking up a two stop ND filter (which nicely fits all three of my enlarging lenses!)

What's cool about that is I can record times for 5.5 inch test prints from 6x6, then remove the filter when I run the head up for 11x11 final output and be right in the ballpark.

DaveT

Mainecoonmaniac · Dec 15, 2011

If you don't want to buy ND filters for your lenses, you can get ND gels for your light source. But l lower the wattage of your bulb first. Another thought is rigging a light dimmer to your enlarger.

chassis · Dec 27, 2011

Clarification: I used a ND gel in the 23XL, above the negative stage in the filter drawer. Pretty inexpensive.

lensman_nh · Dec 27, 2011

Mainecoonmaniac said:
If you don't want to buy ND filters for your lenses, you can get ND gels for your light source. But l lower the wattage of your bulb first. Another thought is rigging a light dimmer to your enlarger.

That will change the color temperature of the bulb greatly. If you use VC paper the grades will be shot as they are calbrated for a 3000K (or thereabouts) light source. Using a dimmer you will lose intensity in the blue spectrum.

Rick Jones · Jan 1, 2012

Make sure the installed bulb is 75W. If the existing bulb is not marked change it out with a PH211. Heat absorbing glass will lengthen exposures. Consider using a VC filter for all exposures. That should double times of your unfiltered exposures. While I have never tried this you might try combining filters, say a VC 2 and 2 1/2. That should really stretch out your times.

Short Exposure Times when printing medium format - is this normal?

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