Omega Replacement Filters

[abruzzi]

Is it possible to get replacement filters for the Super Chromega D Dichroic II heads? KHB sells the entire assembly:

http://store.khbphotografix.com/Yel...per-Chromega-D-and-E-Dichroic-Colorheads.html

I’d prefer to get the small, inch square filter and epoxy it in place. $100+ for the whole arm seems like overkill. The yellow filter is missing on my head, and seems to have fallen off.

 

[RauschenOderKorn]

They have been glued with special heat resistant cement (at least that is what they claim). I doubt that normal epoxy will last very long so close to the lamp.

 

[abruzzi]

They have been glued with special heat resistant cement (at least that is what they claim). I doubt that normal epoxy will last very long so close to the lamp.

The fortunate thing is the adhesive industry makes just about anything you could want. It’s a matter of going through spec sheets. I don’t know what temp things get to but you can easily find adhesives good up to 300C, and probably higher.

 

[MattKing]

Why don't you ask KHB?

 

[abruzzi]

Their website doesn’t list it for sale, so I assumed they don’t sell it. I suppose I can ask them, but I figured I’d ask here if anyone else had gone down this path.

 

[ic-racer]

When I repaired mine I believe I used silicone glue.

 

[MattKing]

Their website doesn’t list it for sale, so I assumed they don’t sell it. I suppose I can ask them, but I figured I’d ask here if anyone else had gone down this path.

They are probably hesitant to sell them unless they can be confident that the purchaser has the technical ability and knowledge necessary.
Alternatively, they might be getting the entire assembly from another source, without access to the district filter alone.

 

[abruzzi]

When I repaired mine I believe I used silicone glue.

We’re you just reattaching, or did you find a replacement filter?

 

[darkroommike]

The head has been discontinued many years and the company is defunct. You may need to find a donor head for parts or pay the tariff.

 

[abruzzi]

unfortunately, if its too costly to fix, it won't get fixed. I won't be printing color, but the yellow would be useful with the magenta to dial in contrast control.

 

[John Koehrer]

How about a surplus sales business like American Surplus? There a few glass suppliers out there.
https://www.google.com/search?q=dic...cAhUC54MKHUcQAkgQsAR6BAgBEAE&biw=1266&bih=716

 

[abruzzi]

How about a surplus sales business like American Surplus? There a few glass suppliers out there.
https://www.google.com/search?q=dic...cAhUC54MKHUcQAkgQsAR6BAgBEAE&biw=1266&bih=716

Some of those might make color printing a challenge! The trick with just any old piece of yellow filter, aside from cutting, is what is the right shade of yellow? I don't know much about that stuff. I have a tiffen screw on yellow filter (12 or 15, I don't remember), can I just cut that up?

 

[btaylor]

Correct me if I am wrong, but didn’t those heads use dichroic filters? Not the same as a camera filter. If the correct part is $100 and available, why not just buy it? Then everything works as intended. We’re spoiled with the ridiculously low prices of old darkroom stuff.

 

[abruzzi]

Correct me if I am wrong, but didn’t those heads use dichroic filters? Not the same as a camera filter. If the correct part is $100 and available, why not just buy it? Then everything works as intended. We’re spoiled with the ridiculously low prices of old darkroom stuff.

Mostly because $130 is a lot to spend when what I need is a filter less than an inch square and to get it I have to buy a whole contraption that it is mounted in that I already have. As I said, if it is $130 to fix, it is most likely not getting fixed.

 

[argentum_et_lux]

Lot of optical supplies like Edmund have dichroic filters. Should be able to get that size for under $30.00 but you need to figure out what the light wavelengths the original covered

 

[AgX]

I don’t know what temp things get to but you can easily find adhesives good up to 300C, and probably higher.

There is glue for cementing glass even standing up to 1500°C.
Though in this very case a pure mechanical fixing might be possible too I guess.

 

[abruzzi]

but you need to figure out what the light wavelengths the original covered

That’s kind of the key. I posted hoping someone else had been down this path before me, but from the responses, it seem s unlikely. I assume the color is probably standard—after all it is part of a set of CMY filters, however the darkness/strength/absorption (or whatever the right term is) would be critical to making the numbers on the lamphouse continue to mean the same thing.

 

[ic-racer]

We’re you just reattaching, or did you find a replacement filter?

Just re-attaching the existing filter.
You don't need an exact matching filter. Any yellow CC filter should do for either B&W or color, unless you are planning on reproducing existing prints with notes on filtration.

Have you priced new dichroic filters without the holder? $100 for one already attached to the arm is reasonable, and may be more cost effective.

If you are on a budget, get a 20"x24" sheet life-time supply of Rosco 4530 Yellow for $7 and cut a little square. Replace it when it deteriorates. The first generation Chromega color heads did not have dichroic filters.

 

[btaylor]

Just re-attaching the existing filter.
You don't need an exact matching filter. Any yellow CC filter should do for either B&W or color, unless you are planning on reproducing existing prints with notes on filtration.
If you are on a budget, get a 20"x24" sheet life-time supply of Rosco 4530 Yellow for $7 and cut a little square. Replace it when it deteriorates.

I like this idea. Lighting gels stand up to heat reasonably well for awhile. And as ic-racer points out you don't need exact filtration-- you're going to dial in whatever is needed to get the contrast/color you want anyway.

 

[argentum_et_lux]

That’s kind of the key. I posted hoping someone else had been down this path before me, but from the responses, it seem s unlikely. I assume the color is probably standard—after all it is part of a set of CMY filters, however the darkness/strength/absorption (or whatever the right term is) would be critical to making the numbers on the lamphouse continue to mean the same thing.

Should be something like 85% passage 550 to 750nm for the yellow
https://www.andovercorp.com/products/dichroic-filters/dichroic-filters/

 

[ic-racer]