26-IK info

[AshenLight]

Hi all,

I just purchased a NuArc 26-1k and after putting in a new lamp and doing some minor setup, it seems to be working well. I have a couple of quick questions...

• The vacuum hoses aren't in the best shape, especially on the bleed valve. Does anyone know the ID of the hoses used in the vacuum system?
• I now find myself having to recalibrate exposures for the processes that I use. Since I need to start thinking in terms of exposure units instead of minutes and seconds, I have to start somewhere. Assuming the integrator is working well and is adjusted for the factory default, what is a reasonable starting point in exposure units for processes that used to take between 6 and 25 minutes (depending on process).

Thanks,

Ash

 

[Jim Fitzgerald]

Ash, these lights are nice to have. I find that exposures in the range of 300 units to 700 units normally cover all of my carbon transfer exposure times. Mine is set to seconds for the units. So I just have to think in terms of 300 seconds etc. Some may be 1 1/2 seconds. Time an exposure and you will easily get it figured out.

Jim

 

[Brickbird]

What Jim said. I agree. My PtPd prints are in the same range as Jim's with an average of about 400 units give or take 100 or so, here and there.....TW

 

[AshenLight]

Hi Guys,

Thanks for the responses. I started calibrating this evening with Mike Ware's cyanotype chemistry on Crane Platinotype and hit 400 EU with a 31 step wedge and Mark Nelson's PDN initial exposure step. I seems that the 26-1K as delivered is about 1.50 to 1.75 seconds per exposure unit. I'll finish these calibrations tomorrow and start on the carbon later in the day.


Regards,

Ash

 

[Nicholas Lindan]

The units/second is completely arbitrary on these machines. Usually, as they come from the factory, they count down at 1 unit/second when the lamp is fully warmed up, that may have changed over the years (er, decades). The count-down rate can be used as an indication of lamp condition: as the lamp ages it puts out less light and the count-down rate will slow down; it is usually a good idea to replace the lamp if the rate goes much below 1/2 of what it is with a new lamp. Although the rate is adjustable it is best to leave the 'calibration' at whatever it may be - the actual number (1 count/second, 1.75 counts/second) doesn't mean a thing except on your machine with your 'calibration'.

As to the hose, any thick wall rubber hose that fits will work OK. If the hose is too flimsy it will collapse under vacuum. You should have the bleed valve fully shut when you draw down and the vacuum should reach 20-25+ inches Hg. Use the bleed valve to release the vacuum before opening the frame.

 

[AshenLight]

Hi Nicholas,

I'm trying to ween myself off of the whole units vs. seconds mindset. I think I've figured out the exposure for Ware's chemistry and will see tomorrow how things go with the next step of the PDN process. Once I have that all set (independent of the calibration of the integrator), I'll start on the carbon tissues I prepared this evening.

BTW: the unit arrived without a lamp, but luckily there is a good graphics art/printing supplier not too far from me so I was able to get a NuArc factory GW114 lamp from them so at least that's one variable I've been able to eliminate. I've heard that the non-NuArc lamps may be an issue as far as consistency of exposure goes.

Thanks,

Ash

 

[Brickbird]

Ash.......I needed to replace my stock lamp in my 26 1k and bought a lamp from Lone Star Light Bulb Supply in Arlington, Texas. It was a MHL-1000 being a metal halide lamp and was $75.00. It has worked great for over 2 years and my exposures have remained consistent. Their phone is 817-633-6001. I dealt with Steve Madden...........................Tav

 

[AshenLight]

Ash.......I needed to replace my stock lamp in my 26 1k and bought a lamp from Lone Star Light Bulb Supply in Arlington, Texas. It was a MHL-1000 being a metal halide lamp and was $75.00. It has worked great for over 2 years and my exposures have remained consistent. Their phone is 817-633-6001. I dealt with Steve Madden...........................Tav

Thanks Tav. I'll need to order a spare so I'll give that a try. I think either Sandy King or Jason Brunner may have used a metal halide replacement in their 26-1K as well and were happy with the results, but I don't remember any details.

Regards,

Ash

 

[sanking]

Thanks Tav. I'll need to order a spare so I'll give that a try. I think either Sandy King or Jason Brunner may have used a metal halide replacement in their 26-1K as well and were happy with the results, but I don't remember any details.

Regards,

Ash

I used a Ushio metal halide bulb in my NuArc 26-1k. You can purchase the bulb from Freestyle for $49. http://www.freestylephoto.biz/5000062-Ushio-MHL1000-1-Nuarc-GW114-Plate-Burner-Bulb?sc=24100

Sandy King

 

[Brickbird]

That's the one, Sandy. Good price over what I paid but I was able to drive over and pick it up. I am still lusting for a new Amergraph ULF unit!....Tav

 

[dlin]

Is the Ushio metal halide bulb a direct replacement for a mercury vapor bulb? Any adjustments required to the circuitry of my unit (Amergraph V28)?

Thanks,
Daniel

 

[AshenLight]

Is the Ushio metal halide bulb a direct replacement for a mercury vapor bulb? Any adjustments required to the circuitry of my unit (Amergraph V28)?

Thanks,
Daniel

I was actually wondering this as well. I would think the strike current would be lower for metal halide as opposed to mercury vapor. I was also wondering if the spectral output of the metal halide bulb would have an effect on integrator calibration. Not a huge issue since I'd run calibrations again after replacing the bulb, but it would be interesting to know.

Ash

 

[Kimberly Anderson]

Just broke the upper filter glass on my 26-1K today. I think what happened was that there was a small contact printing frame resting on the top of the box, and it partially covered the fan. The exposure was particularly long, 300 joules with a very dense negative a student had made. The glass shattered while a group of 9th graders was in the same room processing their film. It scared the crap out of them. So...the lesson is, don't block the fan, even just a little. You might have 'shattering' results. Now, to order a new one. Ugh.

 

[Kimberly Anderson]

Seems that my bulb no longer works. I think the glass breaking might have been the last straw... I think the fuse is OK b/c I can hear the switch working on the inside of the unit, the bulb doesn't go on however...

Ordered that Ushia replacement bulb today. Hopefully that solves the problem.

 

[sanking]

Seems that my bulb no longer works. I think the glass breaking might have been the last straw... I think the fuse is OK b/c I can hear the switch working on the inside of the unit, the bulb doesn't go on however...

Ordered that Ushia replacement bulb today. Hopefully that solves the problem.

Michael,

You can replace the upper glass with tempered glass which should be available locally.

Sandy King

 

[Kimberly Anderson]

Thanks Sandy. Should I worry about that slight patch of ND filter that is on the factory glass? I was thinking of putting a 5% patch there JIC...but wasn't sure if it was necessary.

Just ordered Arentz's new book. I look forward to reading your chapter.

Michael,

You can replace the upper glass with tempered glass which should be available locally.

Sandy King

 

[sanking]

Thanks Sandy. Should I worry about that slight patch of ND filter that is on the factory glass? I was thinking of putting a 5% patch there JIC...but wasn't sure if it was necessary.

Just ordered Arentz's new book. I look forward to reading your chapter.

Hi Michael,

The purpose of the ND patch is to even the light over the entire printing area so it would not be a bad idea to replicate the patch if feasible.

Many NuArc 26-1k(s) units don't have anything to even out the light. My Amergraph ULF-28 has nothing on the tempered glass, but there are patches on the reflector above the glass. I had a 26-1k in the past and it had nothing to even out the light, but the coverage was still excellent at about 20" circel.

Sandy





Sandy

 

[Kimberly Anderson]

I will make a small ND filter and glue it into position when I replace the glass tomorrow. I cut some picture frame glass but will order some tempered glass also. IIRC the ND filter was about 1 inch by 2 inches? Maybe it was closer to 1/2 x1 1/2? Can someone measure theirs? It probably doesn't need to be exact.

 

[sanking]

I will make a small ND filter and glue it into position when I replace the glass tomorrow. I cut some picture frame glass but will order some tempered glass also. IIRC the ND filter was about 1 inch by 2 inches? Maybe it was closer to 1/2 x1 1/2? Can someone measure theirs? It probably doesn't need to be exact.

Michael,

Just to keep you on alert, the purpose of the *tempered* glass is to prevent damage from the high heat generated by the HID lamp.

Sandy

 

[Kimberly Anderson]

Michael,

Just to keep you on alert, the purpose of the *tempered* glass is to prevent damage from the high heat generated by the HID lamp.

Sandy

OH absolutely, I'm definitely clear on that (pun intended). My factory glass wasn't tempered and so I figure that this temporary piece of glass will do fine for a while until I can get a tempered sheet ordered.