Beseler 810 enlarger

**argos33** · 14-Sep-2008, 15:01

Hello,
I am setting up an 8x10 enlarger that appears to be a 4x5 to 8x10 conversion. The cold head light source says "Beseler 810".

I am wondering if there are any 8x10 negative holders made for this or if most people make their own? The previous owner cut out some white plexiglass with glass hinge taped to the underside of it. You then put the negative between the two to enlarge. It works well enough, but I am wondering what was designed to actually go in there?

Does anyone know where I could find a manual for for these units? There is a power cord from the light source that says "Thermal Cord" that keeps it on in addition to the others. I have it unplugged (as it does not appear to be needed) but I am wondering what it's use is. Any help/input would be appreciated. Thanks

Evan

**Jon Shiu** · 14-Sep-2008, 15:04

The thermal thing is just a small heater that keeps the lamp warm so that the light output will be more consistant.

Jon

**Mark Woods** · 14-Sep-2008, 15:21

Also, according to what I've read, the enlarger is supposed to be warmed up for 20 minutes before you use it for consistent results. I use two clear pieces of glass to hold the negative. As long as the glass is clear and clean, it works fine. You can zero out the CT in able to use the variable contrast filters.

Good luck.

**Ash** · 14-Sep-2008, 15:37

I heard another issue with larger negs and warm light sources is the negative can 'pop' and move as it warms, so it's best to keep it in there for a short time to get it up to temperature.

I only overheard that so I may be misinformed.

**argos33** · 14-Sep-2008, 15:55

Thanks everyone, that's what I figured it was for. I found that using anti-reflective (or anti-newton ring) glass for the bottom piece eliminates newton rings on thinner negatives.

I am excited to make some prints, the detail in my "test print" was truly amazing.

Evan

**Ash** · 14-Sep-2008, 16:11

AN glass is a must.

**Eric Woodbury** · 14-Sep-2008, 16:34

The glass/plexiglass sandwich is standard equipment. This adapter was invented by Alan Ross and Beseler then licensed it. If you have a coldlight head that is 12x12, then this is the original design. Later, the light head would overhang somehow.

For use with large negs, the aluminum casting the holds the negative is mounted with the opening for the neg holder at the top. For smaller negs, say 5x7, the housing is flipped over with the opening for the negs on the bottom. For 4x5, you can use the regular position.

A 210mm El Nikkor covers, altho some use the 240mm lenses.

The bottom glass should not need to be AR glass, as the plexiglass in contact with the smooth surface is completely diffused. Rings could appear at the glass/emulsion surface if the negatives were exceeding smooth.

Yes, the thermo is a heater for the coldlight. For the V54 tube, this arrangement can work fairly well, but for some of the 'W' tubes that came earlier, even with the thermo, exposure could drift significantly thus requiring a compensating timer of some sort. This is especially true for high contrast prints with important highlight values.

Finally, alignment: Good luck. There are not enough screws and adjusts to get all the planes parallel. I have had to modify my similar enlarger in a couple places to get enough degrees of freedom to tilt and swing into alignment. It is the nature of the beast.