Above the enlarger lens dust and scratches question

[chassis]

Hello,

Do scratches and dust above the enlarger lens show up on the print? I noticed a defect on an enlarged print, and the defect was neither on the negative, nor on the contact print. I use a Beseler enlarger with above the lens contrast filters. The filter holder drawer has a plastic sheet (“lens”) that the filter rests on. This sheet has crazing or cleaning marks, and I’m wondering if these are showing up in my prints.

Same question for (Ilford in this case) contrast filters above the lens - will wrinkles, creases or scratches show up in the print? If I remove the plastic sheet, will the curvature of the unsupported contrast filter be a problem?

Thanks for any input.

p.s. I searched on this and didn’t see anything that addressed the topic.

[Nathan Potter]

Scratches and dust on condenser lenses and filters between the enlarging lens and the lamp can show on the print as fuzzy defects depending on the degree of collimation of the system (that is the f/no of the illumination system). That problem can be eliminated by using a diffusion light source. Of course if the defects are at the film plane they will be imaged sharply just like the emulsion.

Nate Potter, Austin TX.

[Mark Sawyer]

...That problem can be eliminated by using a diffusion light source. Of course if the defects are at the film plane they will be imaged sharply just like the emulsion.


But then you have a diffusion enlarger, which has a different look from a condenser enlarger.


...The filter holder drawer has a plastic sheet (“lens”) that the filter rests on. This sheet has crazing or cleaning marks, and I’m wondering if these are showing up in my prints.


I'd say just swap out that piece of plastic for a clean piece of glass. As a check, I'd take the negative out of the enlarger and just shine the enlarger's light through the rest of the system onto a clean white sheet of paper or matte board. Move the paper around; and defect inn the system will show up as non-moving marks on the paper. Be sure the focus is set around where it is for your normal use, maybe a bit either side of that too, and check with the lens stopped down.

Seriously, everybody who enlarges should do this little test regularly.

[Michael Clark]

I had a light bulb in my Omega D2V that had some kind of scratch or spot on the frosting inside the bulb that caused problems on the Prints makeing little blotches. Changing to a different bulb cleared up the problem.

Mike

[chassis]

Thanks for the input folks. I have checked the enlarger (Beseler 45V-XL with condenser light source) using Mark's suggestions, and report the following:

1. There is a dark spot on the paper formed by the tip of the enlarger bulb. It is clearly visible, and can be felt by hand, when the bulb is removed from the lampholder. No fix for this except a different bulb or a diffusion light source.

2. There is a seemingly lens-related dark spot (or is it condenser-related) that can be brought more or less into focus with the focusing mechanism and lens aperture. I removed the lens turret and cleaned the lens with a lipstick brush. No effect on the dark spot.

3. I played with the filter drawer and filter, and didn't see any visible defects. The drawer sits between the two condenser lenses, which was news to me - I thought the filter was below the bottom condenser lens. Took me 30 years to notice this. ;)

Question regarding cleaning condenser lenses - I tried this once, and did not attempt to disassemble the lenses because of a pretty heavy retaining ring. I didn't want to pry the ring off and risk chipping the lens. What tool or procedure is needed to disassemble the condenser lenses, so I can thoroughly clean both surfaces of both lenses?

Thanks.

[Mark Sawyer]

1. There is a dark spot on the paper formed by the tip of the enlarger bulb. It is clearly visible, and can be felt by hand, when the bulb is removed from the lampholder. No fix for this except a different bulb or a diffusion light source.

2. There is a seemingly lens-related dark spot (or is it condenser-related) that can be brought more or less into focus with the focusing mechanism and lens aperture. I removed the lens turret and cleaned the lens with a lipstick brush. No effect on the dark spot...

Be aware that the height of the bulb above the condensers is critical. Too high or low will result in the condensers focusing the light unevenly. If your bulb has an uneven spot on it's tip, it's not an enlarger bulb. Enlarger bulbs have a heavier frosting to prevent bright spots from the filament, and are made smooth and even at the tips. I'd invest in the right bulb, for height, frosting, and getting rid of that bump on the tip...

[chassis]

Thanks again Mark. I ordered the bulb online; it was a recommended enlarger bulb. The bulb trademark is located on the neck of the bulb, instead of the normal location on the round end. I was planning to get a new bulb anyway, because the 150W bulb I use requires me to stop the lens almost all the way down, and use 10-15 second printing times. This is with a 4x5 negative printing 8x10 mostly. I will order a 75W and 100W bulbs. I prefer 10-15 second enlarging times, but would like to use the lens in the middle of the aperture range.

The condenser height is set according to the guage on the side of the light source. It is at the lowest setting (marked for 4x5).

I took the condenser assembly out, and cleaned what I could. There is a flat piece of glass below the lower condenser lens, and I cleaned both sides of it. I cleaned both outer surfaces of the condenser lenses, but could not acces the inner (curved) surfaces because I don’t know how to do that.

I reassembled, and re-tested. The dark spot is still there, and it moves when I rotate the condenser assembly. So my belief is there is some dust or dirt inbetween the condenser lenses. This isn’t surprising, because I change contrast filters frequently, and the filter drawer is in between the condensers. This means the cavity between condensers is being opened and closed often.

Has anyone removed Beseler 45-series condenser lenses? What is the proper tool for this? Photos or video of this procedure would be great. Thanks.

[Neal Chaves]

You can replace that flat piece of glass below the the condensers with a piece of flashed opal glass. This will reduce your light output, but will greatly diffuse the light and cure the scratch and defect problems. Surplus Shed may have some.

[Mark Sawyer]

I'm seriously surprised that a dedicated enlarger bulb would have such a defect on its tip! I guess quality has devolved these days... :(


I reassembled, and re-tested. The dark spot is still there, and it moves when I rotate the condenser assembly. So my belief is there is some dust or dirt inbetween the condenser lenses. This isn’t surprising, because I change contrast filters frequently, and the filter drawer is in between the condensers. This means the cavity between condensers is being opened and closed often.

Has anyone removed Beseler 45-series condenser lenses? What is the proper tool for this? Photos or video of this procedure would be great. Thanks.

I haven't messed with a Beseler in quite a while, so can't remember much. But if it's dirt or dust in there, you might be able to blow it out with compressed air through the filter drawer. If you aggravate the dust problem, well, you otherwise had to take it apart anyways! :)

[chassis]

Thanks Neal for the opal glass suggestion, and Mark for the dust suggestion.

[chassis]

Update. I got brave enough to pry off the retaining ring holding the upper condenser in place. Here is the disassembly sequence for a Beseler 45V-XL condenser lamp house. I don't know if there are variations with other Beseler 4x5 condensor lamp houses which would prevent these steps from working on earlier versions.

1. Loosen one black knob and remove bulb assembly.
2. Loosen three black knobs and remove cone assembly.
3. Remove filter drawer.
4. Slide two retaining clamps on the right and left sides of the condenser housing so they are applying no pressure on the housing
5. Lift the condenser housing up and away. Place on a flat surface with a towel under the housing.
6. Remove three screws, shims and spring nuts.
7. Remove flat cover glass.
8. Carefully using a medium length, small flat screwdriver, pry the wire retaining ring away from the barrel of the housing, and up.
9. Remove retaining ring.
10. Remove upper condenser lens.
11. Remove one screw holding spacer sleeve.
12. Slide spacer sleeve up and out by grasping one edge and pushing it so as to make the diameter of the sleeve smaller so it comes out easily.
13. Remove lower condenser lens.

I cleaned inside the condenser housing after everything was taken apart. The lenses were cleaned with windex and paper towels. Assembly is the reverse of disassembly. Pictures would have helped, but I didn't take them. Apologies.

Hopefully this helps with dust.

[Mark MacKenzie]

This may not be related but on my D2 condensors there is a deep scratch about an inch long. If I print at f32, it will show in the print. So...... I print at f8 or so. I've had to use a voltage regulator so my exposures aren't absurdly short. I think it is sharper just a bit at f8 also. Maybe diffraction at f32. I just got a cold light so it should no longer be a problem.

Old condensors are not like a coated lens. They will get dusty and accumulate grime. They need attention. My old Omega would shed black specs of the paint inside.
Best luck,
Mark

[chassis]

Mark, good point about the aperture imaging defects. I want to use a larger aperture, which should also help reduce non-negative-plane defects. I need to change to a lower wattage enlarger bulb to maintain the desired 10-20 print exposure times.