Chromega F color head repair

[Dave Ogle]

Got a used F a few years ago and now have the time to put it to use. It had been store in a garage when I got it and now some problems in side with corrosion. I'm cleaning it up and lubing it. One problem, I found one of the little yellow filters is cracked in 2. Any one got any idea where someone could get filters?

My plan "B" is if all else fails, get some 12x12 filters and use them above the negative.

Thanks, Dave O

[Tin Can]

Go look at APUG, I have a F thread and some others added some info.

I am cleaning one up and rewiring one right now and I am also in Chicago.

[ic-racer]

Got a used F a few years ago and now have the time to put it to use. It had been store in a garage when I got it and now some problems in side with corrosion. I'm cleaning it up and lubing it. One problem, I found one of the little yellow filters is cracked in 2. Any one got any idea where someone could get filters?

My plan "B" is if all else fails, get some 12x12 filters and use them above the negative.

Thanks, Dave O
If it is in 2 pieces you should be able to glue it back together with glass glue while you are looking for a replacement. Being in 2 pieces should not alter its function (as long as there is no light gap between the pieces.)
omega-satter, KHB, Edmund (http://www.edmundoptics.com/optics/optical-filters/color-dichroic-filters/additive-subtractive-dichroic-color-filters/30637), B&H (http://www.bhphotovideo.com/c/product/138051-REG/Omega_92210092_Yellow_Filter_for_Dichroic.html), roscoe (http://www.goodmart.com/products/rosco-laboratories-permacolor-yellow-2-in-glass-dichroic-filter-120-35200-2050.htm) are likely sources.

[Dave Ogle]

Thank you for the replies. Will check other sources in your replies. I have both pieces of the filter. Was going to use super glue, not sure if that's the best. Sent an email to KHB last night.

At first look at the guts of the color head I said "oh no" But once I look at it more and started taking it apart it's not as complicated as it looks.
Dave O

[ic-racer]

Thank you for the replies. Will check other sources in your replies. I have both pieces of the filter. Was going to use super glue, not sure if that's the best. Sent an email to KHB last night.

At first look at the guts of the color head I said "oh no" But once I look at it more and started taking it apart it's not as complicated as it looks.
Dave O

Cyanoacrylate breaks down with heat. There are special glues for glass. Realize the crack should not affect the ability of the filter to manage paper contrast, so a good repair might be all that is needed if you are on a budget or can't find a big enough filter.

The main thing I'd be worried about with a repair is if it broke down over time and let white light through. This would be hard to detect and might create a few headaches until you figured it out.

Realize a new Chromega F head is over $10,000. So $100 for a new filter is not bad.

[brucetaylor]

What a coincidence, I just went through my F dichroic head this weekend. I bought it a year or two ago from someone on this forum and I finally got around to opening it up, cleaning, lubricating, fixing some wiring issues. Since there are 4 filters for each color I would think repairing yellow one with some glue made for glass that will withstand significant heat (it sits 2 inches away from a 250w lamp!) would be a good way to go if you don't replace it altogether. Everything goes into the mixing chamber anyway, so a small deviation on one of the 4 yellow filters isn't going to be a big deal, especially since it would be a constant. I would agree with ic-racer that if a new filter is $100 it would be the best fix.

[Erik Larsen]

A cheap way out for a while might be to take the bulb out that the broken filter corresponds to and print with only three bulbs. I haven't tried it so I don't know if it would effect uniformity of light output, you'll just have to test. I often wish my f head had less power because it just cranks out the light and unless I want to print huge that power is a nuisance requiring short print times or ND filters.

[Dave Ogle]

Just got an email back from KHB, darn, those little thing are $59. each for exact replacement (I hope). I can live with that. ( one or two)

It would be major bucks to replace all. Ilford multi grade 12x12 filters are about $20. each. I would need 4 or 5 of those at least. I got some glass glue. dish washer safe. Also had to find something to lay it flat on to glue it & non stick. Wax paper. Going back down to the shop and try to glue it. Also clean and lube everthing. So far an interesting project.

I used a bunch of Q tips and lens cleaner to clean the other filters. I guess I'll try some test prints with the glued filter before I spring for the replacement. Replacing the light bulbs might be a good idea too.

So, Bruce, how well does your "F" ?
Thanks again for the replies. Dave O

[Luis-F-S]

At least someone still carries parts for these enlargers. One good thing about Durst, Omega, DeVere and LPL. Luis

[Mark Sampson]

I used an F (mounted on a Fotar 10x10) for many years. A few notes: 1) the book said to change all 4 lamps when one blows, in order to maintain color balance. We always did, so can't say if it's really required. 2) Having all four lamps on one side made for unevenness in light output. We had to make a graduated ND mask with lith film (placing it in the filter drawer) to even it out. Can't believe that they want $10k for a new one today- they aren't that complicated. Bet they have a party at OmegaSatter if they actually sell a new one...

[Dave Ogle]

Brand New Chromega F on Ebay $15,000

http://www.ebay.com/itm/Super-Chromega-F-Chassis-w-24-x-32-baseboard-406010-FREE-LAMPHOUSE-/291041809833?pt=LH_DefaultDomain_0&hash=item43c37195a9#ht_1249wt_682

[Tin Can]

And last month a guy couldn't give one away in Chicago.


Brand New Chromega F on Ebay $15,000

http://www.ebay.com/itm/Super-Chromega-F-Chassis-w-24-x-32-baseboard-406010-FREE-LAMPHOUSE-/291041809833?pt=LH_DefaultDomain_0&hash=item43c37195a9#ht_1249wt_682

[Tin Can]

It really is strange how they designed it with all bulbs on one side. I have one I don't use, and my Fotar now sports my DIY LED head. It's evenly lit and runs very cool.


I used an F (mounted on a Fotar 10x10) for many years. A few notes: 1) the book said to change all 4 lamps when one blows, in order to maintain color balance. We always did, so can't say if it's really required. 2) Having all four lamps on one side made for unevenness in light output. We had to make a graduated ND mask with lith film (placing it in the filter drawer) to even it out. Can't believe that they want $10k for a new one today- they aren't that complicated. Bet they have a party at OmegaSatter if they actually sell a new one...

[brucetaylor]

So, Bruce, how well does your "F" ?


Well Dave, I am still in the process of setting up my "F," so I am not sure how well it does at this point. I finally got the chassis fully assembled (it had to be taken apart when I transported it, and it was rusty from being near the ocean for years), the old condenser lamphouse rewired and usable. Now I have to align the beast. It is almost impossible to focus. I got one of those Versa Lab laser tools some time ago, so now it is time to put it to use. Concerning the dichroic head, yippee! it turned on when I was done! I had to do some repairs to the power supply (main power switch was fried, and some wiring overheated as a result), but it seems to work. Next I need to figure out how to attach it to the enlarger as the spacing of the color head is different from the condenser unit. I think McMaster Carr or other hardware outlet will be able to supply the bits to properly space the mounting arms.

I have a question for Randy: can you share some specifics on your DIY LED light source? That might be an option too, with below the lens contrast filters.

[Tin Can]

http://www.largeformatphotography.info/forum/showthread.php?110376-Hacking-8x10-and-11x14-enlarger-LED-head


Well Dave, I am still in the process of setting up my "F," so I am not sure how well it does at this point. I finally got the chassis fully assembled (it had to be taken apart when I transported it, and it was rusty from being near the ocean for years), the old condenser lamphouse rewired and usable. Now I have to align the beast. It is almost impossible to focus. I got one of those Versa Lab laser tools some time ago, so now it is time to put it to use. Concerning the dichroic head, yippee! it turned on when I was done! I had to do some repairs to the power supply (main power switch was fried, and some wiring overheated as a result), but it seems to work. Next I need to figure out how to attach it to the enlarger as the spacing of the color head is different from the condenser unit. I think McMaster Carr or other hardware outlet will be able to supply the bits to properly space the mounting arms.

I have a question for Randy: can you share some specifics on your DIY LED light source? That might be an option too, with below the lens contrast filters.

[brucetaylor]

Very cool, Randy-- thanks. The display LED panel looks like a good bet, and inexpensive, too.