The time, when the bulb is ON!
Yesterday I launched my recently bought Beseler 23CII-XL and started with smaller-format papers - 8x10". What surprised me, was the time I need to do the proper print: it is no longer than two seconds on f22! When using multigrade filters, it goes down to f11-f16.
The lens is Componon-S 80/4, bulb standard 75W/230V, developer Bromophen 1:3.
I've used various papers: Ilford (Multigrade, Ilfospeed), Kentmere, with old Kodak bromide papers the time needs to be tripled and you're lucky if it's not fogged - but it's another story.
Prints are fine, but 2s on f22 seems a bit strange. My idea is, that the optics of its condenser produces strong light, as 23C is designed for large paper sizes. Am I right?
The condenser system of the Beseler 23C concentrates the light into a circle not much larger than the diagonal of the opening in the negative carrier when the lamp house height is adjusted to accommodate the format in use.
However, a 2 second exposure at f/22 seems unlikely unless:
1. The lens is failing to close down as marked.
2. The negative is unusually thin.
I’d expect to see 8” x 10” prints on a Beseler 23C requiring 8 to 12 seconds depending on the negative density and the paper speed at the optimum f/8 aperture for this lens.
One thing you can safely do is to lower the lamp house to focus its light into a larger circle, such as the 6 x 9cm setting.
That will reduce the light intensity and increase printing time.
I’d first check the lens to verify that it is actually stopping down as indicated. If the aperture is stopping down correctly, then I’d next compare the density of the negative you’re trying to enlarge to a negative known to have correct density.
If the density is correct, I’d recheck that the bulb is the correct voltage. If that’s ok, then you can defocus the condensers to reduce the light intensity at the negative.
You can certainly use a light meter to measure the light intensity projected to the easel at the 8” x 10” print setting without a lens. Then other 23C users can post their readings at the same setting. For that we’d need to know the format setting of the lamp house, as this varies the light intensity at the easel.
Holy moley, two seconds is way wrong! I would agree that 10 seconds at f8 would be what to shoot for, no more than that at f11. Are your negatives thin, does the lens stop down when the lever is actuated? I have a couple of 23CII's one is dichroic and doesn't throw that much light.
You wouldn't happen to have a color dual dichro head on the enlarger and you are using it in condenser mode without that chronic light integrator installed?
I placed a normally exposed and developed 6 x 6cm Kodak T-Max 100 negative into the carrier of my Beseler 23C condenser enlarger with 75w 120v PH-140 opal photo bulb (same lumen rating as the 75w 230v PH-1400 bulb used in Europe and the UK).
I focused the image using a 75mm f/3.5 lens, which is similar to an 80/4 lens. The negative-to-print distance was 552mm to project an image slightly larger than needed to make an 8” x 10” print.
I made the exposure of 8 seconds at f/8 through an Ilford MG #2 ½ filter. The print looks approximately correct for density and contrast. The paper is Ilford MGIV RC. The enlarger is equipped with a sheet of heat absorbing glass in the upper filter slot (holds back 0.3 stops).
Had I not had the heat-absorbing filter in place, the exposure would likely have been 6.5 seconds.
With the HA glass, an f/22 exposure would be 64 seconds. Without the HA glass the exposure would likely be 52 seconds.
The 75/3.5 lens I used should transmit about the same amount of light at the same aperture as an 80/4 lens at the same magnification (same projection size).
Then I removed the negative (leaving the carrier in place) and opened the lens to f/4. I set the meter to ASA 1000 and 8 seconds and placed it with the diffuser facing up directly under the lens and switched on the lamp.
The reading was f/45 + 0.4f with the HA glass and f/45 + 0.7f without the HA glass. This white light reading was taken without the Multigrade filters present. Your machine should give similar readings if everything is correct.
Last edited by Ian C; 09-26-2011 at 05:17 PM. Click to view previous post history.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
I have not used a 23C, but I did pick up a Saunders/LPL into which someone had installed a generic halogen in the lamp house instead of the ESJ that was required. It did not take long to figure out that something was wrong. You can check your bulb here. Buy two.
Tom, on Point Pelee, Canada
Ansel Adams had the Zone System... I'm working on the points
system. First I points it here, and then I points it there...