Well, I just went down and cut open the box on a brand new one to make sure it is what I was told it was. It is a 35mm mixing chamber. The guy I bought my enlarger had the 4x5 in the head, a 6x7 in a baggie, and a brand new unopened 35mm chamber.
I never print 35mm on this enlarger, so I hadn't actually cut the tape on the box to check it out.
Maybe they don't make these anymore?
See if your enlarger has high/low setting. My Omega D5 has one and I always print on High. Somehow I don't think your time is right. Just yesterday I printed a 11x14 print cropped from 6x4.5 negative using 85mm Nikkor. That's little over 6x enlargement just like you did, and my time was about 16 sec at f16 (or f11? I don't have notes with me).
Anyway, check the lamp - maybe the bulb is for the wrong voltage; check voltage stabilizer - does it provide the correct voltage; filters - are they dirty or stuck in the wrong position; lens - does diaphragm move; mixing chamber - is the white liner missing or heat resistant glass filter dirty? Oh, and check the paper and developer - maybe expired or wrong dilution? I know, silly questions, but that's what I would try to check and not necessarily in that order.
90 sec is not bad!! I have a really difficult negative and it has a base exposure of 2min 40sec and then I have to burn the sky in for 13min moving a card up and down to smooth the horizon. It makes your arms very tired =( It's 35mm negative on tmax 400 with box development in d76 1:1. I'm printing 8x10 fotokemica emaks grade 3, a 50mm f2.8 el-nikkor stopped down to 5.6 and a beseler mx45 with a zone 6 cold light head.
Luckily I spend a while tonight taking my Dichro 45 color head apart and found what was wrong with it. I'm excited to try printing the same negative with this head which I think is much brighter. I just hope the vibration from the fan isn't too severe.
There is still a problem with my color head, the cam or gear for the yellow filter is slipping on the axle and won't move out of the light path without flipping the switch to move all the filters together so I can't use it for VC paper till I fix it. Any suggestions?
Lens focal length does not affect exposure per the first law of thermodynamics. Perhaps your meter is off axis to get 0.85 stops difference when you measure.
Originally Posted by Ian C
The difference was calculated, not measured, in post #9.
Your comments prodded me to measure the difference.
I focused a 35mm negative using a 50mm lens to cover the width (short dimension) of an upside-down scrap print at about 5.5” projection width and placed my meter on the print with the diffuser at the center facing up. I used ASA 1000 and 2 seconds and got a reading of f/8 + 0.4f.
Then I redid this with a 90mm lens. Both lenses set at f/5.6. The reading was f/8 + 0.1f, so the actual measured difference was 0.3f. My calculated value didn’t agree.
Then I reviewed the calculations I’d used. I had erroneously used an equation for the SAME focal length lens at different projection distances. This doesn’t apply to two lenses of different focal lengths.
I promptly self-administered a “dope slap” for carelessness.
Thanks for catching the error.
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I had the same problem with my Beseler 23, with dichro head. When using the diffusion set up, black and white took 90 to 120 seconds, and color took about 20 seconds. Apparently color paper is more sensitive. So, I use the condensor set up for B & W, and the diffusion set up for color. With the condensor, exposure times for B & W are about 20 seconds.
I don't know it the condensor set up is possible on the Beseler 45, but someone else should know. Good luck.
"Lens focal length does not affect exposure per the first law of thermodynamics. Perhaps your meter is off axis to get 0.85 stops difference when you measure."
35mm > 5x7 print
how much bellows extension for the 50mm lens?
how much bellows extension for the 90mm lens?
how much exposure compensation for each?
the 90mm with naturally make a smaller print size so less extension / compensation.
I guess this will need a side by side comparison to prove out.
"I don't know it the condensor set up is possible on the Beseler 45, but someone else should know."
There are a few at eBay right now. Get the cheapest complete unit, they are all the same. Rather heavy for shipping, work very well. Condition, condition, condition.
Bellows factor is the same for both lenses (magnification does not change).
Originally Posted by phfitz
Last edited by ic-racer; 10-11-2011 at 05:58 PM. Click to view previous post history.
I have 3 mixing chambers for my Dichro! I guess Besseler quit making the others.
As for Cyan filtration, it has no effect EXCEPT to cause long printing times! Cyan filtration must ALWAYS be set to zero.
I get 12" at f11 for an 8x10 from 35mm. This is with a 35mm chamber. I get the same from 4x5 to 8x10 with a 4x5 chamber. This is with a 30M which is what the manual with it says is grade 2 for Ilford paper. The chambers vary from 35 - 120 - 4x5 by about one stop steps.
It should have no effect on printing time. It (should) block light to which the paper has no sensitivity.
Originally Posted by Photo Engineer
Last edited by ic-racer; 10-11-2011 at 06:13 PM. Click to view previous post history.