Question about Beseler 45S Colorhead Diffusion Chambers

[brent8927]

This may sound very stupid and/or clueless. But, I just recieved a Beseler 45S colorhead. I'm a curious fellow and also wanted to check and make sure the interior parts were in good shape, so I took apart the diffusion chamber (a 4x5chamber, if it matters). I was a little surprised to find two moulded styrofoam pieces inside. It seems like they're meant to be there, and not just for protection during shipping. My impression is styrofoam is a great insulator and thus it would be fine to have it so close to halogen bulbs, but at the same time it just seems so odd to me, and that perhaps maybe the styrofoam actually was just only supposed to be there to protect during shipping. But it's angled at 45 degrees and is white, and the colorhead most certainly works with the strofoam in place.

Does anyone know if the styrofoam should be there?

 

[Nick Zentena]

Yup. Eventually it might yellow then you need to replace it but if it's white it's good.

 

[brent8927]

super!

 

[Chan Tran]

Yeah the styrofoam is supposed to be there. My older dichro DG is just painted white with a piece of translucent plastic in the middle. The styrofoam would be much cheaper and works well.

 

[Photo Engineer]

There is a zero balance adjustment on the top of the sensor on mine so that you can zero the system as the white material, whatever they happen to use, colors as it ages.

You will find about a 1 stop difference between the diffusion chambers, so if you use a 4x5 chamber with a 6x7 neg and then the 6x7 chamber with the 6x7 neg, you will gain about 1 stop. I find the same true with the 35mm chamber. I have all 3.

PE

 

[fschifano]

The same is true for the Omega Chromega II heads. They're lined with styrofoam. I'm sure it keeps the outside of the head from heating up too much and it makes an excellent reflector. The original lining in my mixing chamber had yellowed from heat and age, so I replaced it and now it performs like new. It was very easy to do and well worth it.

 

[PHOTOTONE]

Even if the styrofoam yellows it is not really a factor in getting a good print, as you can correct for it in your color balance.

 

[fschifano]

Yes, that's true, but it does make a difference. If you're using magenta filtration for a high contrast print, you need to dial in more to get where you want to be. It also lowers the upper limit of the contrast you can wring out of the thing. On the flip side, VC papers used with no filtration print softer than they normally would. Finally, printing times increase with a yellowed mixing box. OK, that may be a good thing, but it is something to take into account.