NuArc 26-1K

[Andrew ren]

Greetings all,

I got a chance to pick up a 26-1k from a local press shop. I am just about to start my pt/pd printing process, and have been looking for a uv box and quality contact frame for several days... Now, here comes the questions:

1. is this NcuArc thing is the ideal stuff for the pt/pd printing(up to 20x24)? I mean this to me is the all-in-one gear, I got vacuum frame and uv box built in, all I need the chemicals and paper, etc..

2. I fired it up today and find out the light bulb seems dim to me, as I always been told the contact frame should always be within 2-3 in under the uv light source, but there is about 16in from the bulb to the thick glass surface on my 26-1k.

Also the pump guage seems not moving up even I turn the thing on for 1 min, I guess there must be a leaking somewhere..

is there anywhere Ican get an operational menual?

Cheers

Andrew

[Jim Fitzgerald]

Andrew I have been having trouble with my 26 1KS for a while. I spoke to the tech at M&R companies. They handle the NuArc line. You need to make sure you have a dedicated 20 amp circuit for the unit. Take the top off and make sure everything inside is tight and nothing has come loose in the move. Make sure there is nothing that has been disconnected. Check to see that the light integrator eye is pointing at the bulb. Don't worry about getting shocked by touching anything in the top of the unit, I didn't! I'm no expert so still be careful I can't guarantee that you won't.
To give you an exposure example I have a 450 watt mercury vapor bulb that gives me 1 hour exposures bout 10 inches from my vacuum frame and the NuArc gives me 12 minutes. This is for carbon transfer. I think you will be surprised by the power of these things. You unit needs time to warm up and as I understand it this is one of the differences between the 1k and the 1KS. Check the seals around the frame and the tube for leaks on the vacuum. Is there a bleeder valve on the front of the unit? If so make sure it is closed. If you need help you can call Israel in tech services at 1-800 736-6431. He was of great help to me.

Jim

[Brian Bullen]

Andrew,
The gauge on my Nuarc doesn't move either but the vacuum frame works fine. I have never had issues with registration and usually let the vacuum run for a minute before exposing. If you watch the vacuum pad do you see it raise towards the glass?

[Andrew ren]

Jim,
thank for the tips. I will rip it apart this weekend clean it, seal the rubber thing.. see if it works.

photobulley, are you sure its the bed-pad pops up towards the glass? I thought is sucking the glass towards the rubber pad as I found a hole on the upper left corner of the rubber bed... hmm.

Thanks

Andrew

[Don7x17]

And if you change bulbs, avoid directly handling -- leaves an oil film that can cause early failure. Wear gloves or use a paper towel, etc, to hold the lamp.

[Jeremy Moore]

photobulley, are you sure its the bed-pad pops up towards the glass? I thought is sucking the glass towards the rubber pad as I found a hole on the upper left corner of the rubber bed... hmm.

The hole is where air is being sucked out of the sealed area created by the rubber pad and the glass. As the air gets sucked out of the space the rubber bladder will expand to fill the void and move up towards the glass pressing the negative/paper into contact with the glass.

[Brian Bullen]

Jeremy said it perfectly.
My 26-1k was well used when I purchased it, as a result the inside of the bulb looked like it was coated with a black metallic substance. I ordered a new bulb and the difference in brightness and printing times was amazing. Here is a link to a supplier of bulbs. http://www.bulbconnection.com/ViewItem/bcrw/itmid/1958/oc/MHL-1000%2F1/item.html
Like Jim F my Nuarc has a number of quirks, but she still has some life left.:)

[Andrew ren]

And if you change bulbs, avoid directly handling -- leaves an oil film that can cause early failure. Wear gloves or use a paper towel, etc, to hold the lamp.

Don, yes, I will wear my Michael Jackson's leather gloves. :D

Thanks

Andrew

[Andrew ren]

The hole is where air is being sucked out of the sealed area created by the rubber pad and the glass. As the air gets sucked out of the space the rubber bladder will expand to fill the void and move up towards the glass pressing the negative/paper into contact with the glass.


I see.
----
photobulley, Thanks for the link.

BTW, love both yours and Jeremy's work, very nice!

cheers

Andrew

[Jeremy Moore]

They also carry the Ushio bulb at Freestyle photo: http://www.freestylephoto.biz/5000062-Ushio-MHL1000-1-Nuarc-GW114-Plate-Burner-Bulb

It's $13 more expensive there, but I like to support Freestyle as they carry a lot of the more esoteric things I like to use.

[Jeremy Moore]

BTW, love both yours and Jeremy's work, very nice!

Same to you! Just checked out your site. Especially love County Road #5, gorgeous.

[Brian Bullen]

Andrew your photographs are outstanding, thank you for the compliment!

[Jeff Bannow]

On the vacuum - I have the same model. Make sure that the vacuum is turned on, that the knob on the front of the unit is closed (this is the air release valve), and on mine I have to push the glass a bit to start the suction.

It does take over a minute for the bulb to come up to full brightness - when it does it is so bright it hurts to look at.

[Jeremy Moore]

On the vacuum - I have the same model. Make sure that the vacuum is turned on, that the knob on the front of the unit is closed (this is the air release valve), and on mine I have to push the glass a bit to start the suction.

This is not what should be required for a NuArc in working condition. You should be able to leave the bleed valve on the front panel set where you want and keep it there all of the time, you should not need to adjust it every time. I use ~8psi on my NuArc when printing and leave the bleed valve adjusted for this strength vacuum all of the time--once the negative/coated paper combo is in the frame with the glass down I just need to hit the vacuum button and wait 10-15 seconds. Don't expect the vacuum to jump straight to full either, it will take 10-15 seconds to come up to full pressure (if you're using ~8psi) as it has to suck out the air to create the void and this just takes a little bit. Finally, if you have to push the glass to start the suction then you can clean the rubber and glass to make sure there's not something causing it to not create suction or you may need to shim beneath the rubber mat to even the contact out. I built up layers of gaffer's tape underneath my rubber mat to even out the contact.

[Jeremy Moore]

It does take over a minute for the bulb to come up to full brightness - when it does it is so bright it hurts to look at.

And is putting out so much UV light that looking direction at it can cause photokeratitis (inflammation of the cornea) and even permanent eye damage. I put a skirt around my NuArc to reduce ambient UV light in the room.

[Jim Fitzgerald]

I have special goggles with flip up lenses! real sci-fi looking when I print. I can scare the kids in my apartment complex if I forget to take them off!

Jim

[Jeff Bannow]

This is not what should be required for a NuArc in working condition. You should be able to leave the bleed valve on the front panel set where you want and keep it there all of the time, you should not need to adjust it every time. I use ~8psi on my NuArc when printing and leave the bleed valve adjusted for this strength vacuum all of the time--once the negative/coated paper combo is in the frame with the glass down I just need to hit the vacuum button and wait 10-15 seconds. Don't expect the vacuum to jump straight to full either, it will take 10-15 seconds to come up to full pressure (if you're using ~8psi) as it has to suck out the air to create the void and this just takes a little bit. Finally, if you have to push the glass to start the suction then you can clean the rubber and glass to make sure there's not something causing it to not create suction or you may need to shim beneath the rubber mat to even the contact out. I built up layers of gaffer's tape underneath my rubber mat to even out the contact.

Yeah, I figure I need to clean the rubber and probably level it at some point.

Interesting about the valve - I use it as I was shown by the previous owner. I'll have to try leaving it in place next time.

[Jeff Bannow]

I have special goggles with flip up lenses! real sci-fi looking when I print. I can scare the kids in my apartment complex if I forget to take them off!

Jim

Cool idea - do you know what they are called? Right now I just avert my eyes when printing, but something longer term would be good.

[Jeremy Moore]

I have special goggles with flip up lenses! real sci-fi looking when I print. I can scare the kids in my apartment complex if I forget to take them off!

Jim

Jim, these just sound too fun!

[Andrew ren]

Yeah, I figure I need to clean the rubber and probably level it at some point.

Interesting about the valve - I use it as I was shown by the previous owner. I'll have to try leaving it in place next time.

jbannow, there are there hinges on the glass, probably 2 on the back, one handle @ front to be precise, my problem is the whole rubber bed shift too far towards the back, the edges of the back hinges were caught on the outer rubber rim, that leaves a gap.

check out yours I bet the rubber bed was shifted over, I just came out of the basement, spent whole noon time to clean it and re-Velcro the entire bed.. its working wonderfully..

and for the valve thing, I agree with Jeremy, you just have to adjust to a point, and every time as you fire up the pump, if will reach and stay there...

Now I am ready to get wet...:D

Thanks everyone.

Andrew

[Jeff Bannow]

jbannow, there are there hinges on the glass, probably 2 on the back, one handle @ front to be precise, my problem is the whole rubber bed shift too far towards the back, the edges of the back hinges were caught on the outer rubber rim, that leaves a gap.

check out yours I bet the rubber bed was shifted over, I just came out of the basement, spent whole noon time to clean it and re-Velcro the entire bed.. its working wonderfully..

and for the valve thing, I agree with Jeremy, you just have to adjust to a point, and every time as you fire up the pump, if will reach and stay there...

Now I am ready to get wet...:D

Thanks everyone.

Andrew

I'll definitely check that out. Thanks!

[Jim Fitzgerald]

Jim, these just sound too fun!

Okay, you guys these things are cool! I don't know where you get them as they came from my good friend Gordon Chapple's estate. They have these really cool dark green lenses that flip up to clear lenses. If i put the appropriate head gear on i don't need a Halloween costume! Sorry I don't know where to get them. maybe Welders goggles?


Jim

[Andrew ren]

Okay, you guys these things are cool! I don't know where you get them as they came from my good friend Gordon Chapple's estate. They have these really cool dark green lenses that flip up to clear lenses. If i put the appropriate head gear on i don't need a Halloween costume! Sorry I don't know where to get them. maybe Welders goggles?


Jim

:D

I bought a 100% Uv a&B proof glassware from Marks work warehouse shop this afternoon here local.

[Jan Pedersen]

My rubber bed does move to but towards the front. It's not a big deal and i can print a few sessions before i need to reposition.
I have always used maximum vacum so perhaps i could try to turn it down a bit and maybe not have to reposition the rubber bed so often.

I don't remember where i bought my goggles but a google search should bring up some options. Don't use it without goggles unless you walk out of the room when you expose your paper. Eyes are not easily replaced.

[E Thomson]

Frankly I have no idea why anyone thinks they should be bleeding off the vacuum. The vacuum press will work at its most efficient (will hold the materials tightly registered) when it is allowed to operate at full force. The valve is there so you can release the vacuum quickly and open the lid. That's why it's labeled "Release" (on my 26-1KS). Just let out the vacuum by turning it counter-clockwise, then close it clockwise again.

My unit came with self-adhesive velcro holding the rubber mat and seal assembly in place so it doesn't shift. Strips of hook stuck to the metal bed and strips of loop stuck to the mat assembly.

My unit also came with a sheet of corrugated cardboard laid under the mat, but cut to a size that would fit loosely inside the vacuum area. This has the effect of lessening the volume (or empty height) of the cavity within the seal. If you are only pressing thin materials, it means the vacuum will draw more quickly.

[Colin Graham]

For digital negatives on some media, the vacuum can practically transfer the ink from the negative to the interleaf or emulsion if left all the way up. On my vacuum frame 5" of mercury is plenty to hold everything tightly sandwiched together, even with unruly carbon tissues. But then again mine is a DIY, so not sure about the nuarc.

[D. Bryant]

For digital negatives on some media, the vacuum can practically transfer the ink from the negative to the interleaf or emulsion if left all the way up. .

IMO, this is more of a function of the negative substrate than the vacuum setting. I've had this occur with products like Ultrafine Clear Film printed with colored ink. UCF works best with black inks, at least Epson black inks. This has never occurred with me using Pictorico or a Pictorico work alike such as Arista transparency film.

Never the less working at a reduced vacuum may help prevent loss of water content of an emulsion which is usually important to maintain consistency with most alt. processes. A work around is to place the negative and sensitized paper between sheets of mylar.

But this is probably old news for you,

Don Bryant

[Jason Greenberg Motamedi]

With some soft papers I notice that with full vacuum the NuArc rubber mat can leave marks which are difficult to remove, even after a long chemical soak.

[clay harmon]

The reason is that an excessive vacuum will dessicate a paper that has been coated. This is important with pt/pd processes because the sensitivity (printing speed), image color, and contrast of the paper are influenced by humidity. A too-dry palladium print will be slower, browner, lower contrast and have less dmax. A sheet of mylar between the back of the print and the blanket will help slow down this dessication, but a high vacuum and long exposure will eventually dry out the paper no matter what steps you take. Using the minimum vacuum to get good solid contact between the negative and and the coated paper will buy you some leeway.



Frankly I have no idea why anyone thinks they should be bleeding off the vacuum. The vacuum press will work at its most efficient (will hold the materials tightly registered) when it is allowed to operate at full force. The valve is there so you can release the vacuum quickly and open the lid. That's why it's labeled "Release" (on my 26-1KS). Just let out the vacuum by turning it counter-clockwise, then close it clockwise again.

[Andrew ren]

this is interesting.

just had a test, put a paper towel under the glass, cranked to 15, the marks left over @ the back of the paper seems "permanent".

so whats the "ideal" pressure for standard pt/pd printing then?

[Jeff Bannow]

The reason is that an excessive vacuum will dessicate a paper that has been coated. This is important with pt/pd processes because the sensitivity (printing speed), image color, and contrast of the paper are influenced by humidity. A too-dry palladium print will be slower, browner, lower contrast and have less dmax. A sheet of mylar between the back of the print and the blanket will help slow down this dessication, but a high vacuum and long exposure will eventually dry out the paper no matter what steps you take. Using the minimum vacuum to get good solid contact between the negative and and the coated paper will buy you some leeway.

I suppose another option would be to use a contact print frame instead of the built in vacuum easel ....

[Jeremy Moore]

I suppose another option would be to use a contact print frame instead of the built in vacuum easel ....

Not if you want the degree of contact easily possible with the vacuum easel vs. the use of a contact frame, especially with 16x20 and 20x25 prints.

[D. Bryant]

With some soft papers I notice that with full vacuum the NuArc rubber mat can leave marks which are difficult to remove, even after a long chemical soak.
Jason,

Pickup a sheet of plastic from a quilting store. Normally it's using for cutting patterns but you can use it in the vacuum easel to eliminate transfer of the bed texture.

You can also use a cutting pad also found at quilting shops. It has a nice grid if you want to keep the paper and negative positioned in the same spot each you print. The 26K has a little falloff around the corners and edges.

Don

[Michael Mutmansky]

Another reason to avoid full vacuum is the 'sponge' effect. This happens when a small (but deadly) amount of liquid remaining deep in the paper is squeezed out of the fibers and onto the negative. By the time the print comes out of the exposure unit, the negative is permanetly destroyed. This happens if you put the print in a little too early...

Backing off on the pressure to only that necessary to hold the paper and negative in good register (and then a little) avoids this problem.

Frankly, I have no idea why anyone thinks they should run the vacuum without using the bleeder valve. Apparently, there's no absolutes in alt. processes...

---Michael


The reason is that an excessive vacuum will dessicate a paper that has been coated. This is important with pt/pd processes because the sensitivity (printing speed), image color, and contrast of the paper are influenced by humidity. A too-dry palladium print will be slower, browner, lower contrast and have less dmax. A sheet of mylar between the back of the print and the blanket will help slow down this dessication, but a high vacuum and long exposure will eventually dry out the paper no matter what steps you take. Using the minimum vacuum to get good solid contact between the negative and and the coated paper will buy you some leeway.

[Andrew ren]

ok guys, now as my darkroom almost there.
Now another question will be, how long will it take for the 26-1k to get warmed up, to a full-strength output?

and as warmed up, then shut it down, load the sandwich up then turn it on again, is that going to hurt the bulb? I mean in such a short period, on-off-on....

Cheers


Andrew

[sanking]

ok guys, now as my darkroom almost there.
Now another question will be, how long will it take for the 26-1k to get warmed up, to a full-strength output?

and as warmed up, then shut it down, load the sandwich up then turn it on again, is that going to hurt the bulb? I mean in such a short period, on-off-on....

Cheers


Andrew

Andrew,

It takes about two minutes for the mercury vapor bulb of the NuArc 26-1k to reach full radiation. After it shuts down you will need to wait several minutes before powering it back up. I don't think you will damage the bulb by trying to power up too soon, it just will not light up.

Sandy King

[Andrew ren]

Thanks Sandy!

I just went down the basement, measuring around, and decided to move the 26-1k to the end of the basement(left of the pic), has its own corner and build a curtain bar with black cloth on it. so when the curtain in place, the burner has its own little chamber, and same time I can do my coating on the other side of the basement.

Andrew

[Michael Mutmansky]

Do not do this. It will unnecessarily shorten the life of the lamp (bulb to laymen).

The integrator is part of the unit specifically so that you don't need to warm up the lamp.

Get the integrator working properly, and you will get consistent and predictable results out of the machine so that 200 units is 2x 100 units, and so fourth, even though 200 units will not be 2x the 100 units on a clock.


---Michael

[Ron McElroy]

What Michael said.....
As one who used these type machines in there intended environment ie, printing prepress, the integrator will take care of the warmup part of the exposure. Just turn the unit on before using and left the electronic and bulb stabilize, use as needed and then shut down at the end of the session. At work we always left the machines on until shut down at night.

[Andrew ren]

Thanks Michael and Ron!

Cheers

Andrew

[Brioni Foo]

My friend picked up a NuArc from a print shop going out of business. The unit worked until we moved it to the basement. The problem now is that the bulb does not come on. We get a quick, dim flash and then nothing. Vacuum is fine. We heard recalibrating the integrator might solve this problem. Does anyone have any resources/instructions on recal'ing the integrator? Does anyone have any advice?? Thanks for any help you can offer.

[clay harmon]

Probably either the bulb is gone or the starter board needs to be replaced. Either one is an easy operation. Replacing the starter board requires you to pop the top off the machine and keeping track of nine screws, but is about the same level of difficulty as adding ram to a computer. Call Nuarc service line ( Israel is who you want to talk to, if memory serves) and they can get you what you need.

[Andrew ren]

Brioni,

if every time it gives you a quick flash and then nothing coming up, I would say the circuit board problem...

Israel is the person to talk to, nice guy!

keep us in the loop..

Cheers

Andrew

[Andrew ren]

hello everyone,

very frustrating here..

spent 2 nights just try to figure out what will be the base exposure for my nuarc 261k.

I didn't try to calibrate the integrator, and the bulb seems fine...

now, after last night's intensive work, i think my base value seems sit between 150-300unit.

so here is what i did, i cover up 5/6 of the strip and only exposed the first 1/6 @50units, then moved the card board another 1/6, gave another 50unit exposure..
in such a manner, 50/50/50/50/50/100(so the final is 100/150/200/250/300/350 ), the last one i removed the whole card board, gave the whole strip a 100 unit. it turned out as showing on the attached pic(it is the left part pic).
then right after this strip, I did another one, as showing on the right part of the pic. this one is @ 175/200/225/250/275/300.

the result is very confusing, as I was expecting a finer scale on the 2nd test strip(right hand side)

I have been keep doing this for 2 nights and still get nothing and of course, without a firm base exposure, I can go nowhere!


Thanks


Andrew

[PViapiano]

What process are you trying to calibrate for?

You should be using full strips, the entire step wedge exposed at the same amount of units...are you using digital neg strips or Stouffer's?

You should expose the whole strip, depending on the process, until you get the first two steps equal to dMax black and then see a difference in the next strip (getting lighter)...that is your base time.

Don't cover up partial strips, that doesn't work!

The way you are doing it, you would need several step wedge strips and you would cover each whole step wedge for each exposure of 50 units or whatever your choice of exposure is.

For example, for my pt/pd printing in the sun (and it doesn't matter what source you use, the calibration works the same) I get the first two steps black at 7 minutes. That's my base time.

Now whether you're using Stouffer's or a digi-neg, that is something else to take into consideration and will dictate where you go from here...email or PM me if you need more clarification!

[Andrew ren]

Thanks PViapiano.

i did almost exactly same as this:

http://www.luminous-landscape.com/tutorials/platinum.shtml

its for pt/pd printing too.

seems i got another inconsistency problem with nuarc again. the second test strip's 25units step difference was not showing at all!


Andrew

[PViapiano]

Andrew...

There are many variables in the pt/pd process, but that being said, I would expect 25 units not to show anything as well. Most people I know who use the 26-1K, are somewhere near 400 units with Fabriano EW paper, 1:1 FO/palladium and possibly one drop of 2.5% NA2. Arches Platine has very similar exposure characteristics, in my experience.

But please...do yourself a favor and expose a Stouffer step wedge! Don't do what is recommended in the article (using a clear sheet of Pictorico).

The Stouffer step wedge is the reference for all alt printing. It will tell you everything you need to know if you know how to read it.

And, get yourself the Arentz book and live and breathe it...

[PViapiano]

Andrew, if you don't have a Stouffer, then the next best thing is to download QTR and print the 21 step wedge supplied in the ZIP file. I'm assuming you have an appropriate Epson printer that is supported by QTR?

Then go to Ron Reeder's site and download his Pd curve for QTR and install it. Print the 21-step negative with that curve. Expose for approx 400 units, and you'll be very close. Make sure your mixture is 1:1 (12 drops/12 drops) pure palladium or with an added single drop of 2.5% NA2.

I believe the article you referenced mentioned using 10% NA2 in the example 5x7 prints. That is a huge amount of NA2 for that size print unless the neg is very, very thin.

While you're there, read everything Ron's written about digi-negs and palladium printing.

Good luck!

[PViapiano]

On page 5 of Ron's pdf palladium printing manual, he mentions an alternative that sounds similar to what you're trying to do. You should read it and see if you can make that fit or how it jibes with your method from LL.

[PViapiano]

One more....Andrew, I looked at your website...beautiful images. Those are pt/pd, right? How have you been exposing them...sunlight? Or did you have another UV unit?

If so, how did you calibrate for those?

Or are you now calibrating for your first pt/pd images?

[Kerik Kouklis]

Andrew, your basic approach is sound, but you should try making the increments in exposure larger. Clearly, 50 is not enough, so you could start with 100, 200, 400 and 800 units for example. It's likely you will hit pure black somewhere (either between 200 and 400 or 400 and 800, I would think). Then, do a second test that divides the closest pair from the first step into smaller pieces. For example if your first test indicates pure black between 400 and 800, do a second test like this: 400, 500, 600, 700 and 800.

I don't really agree with Paul's approach, but it works for him and others as well. The problem with using a Stouffer step wedge is that the base fog is much lower than the base fog of pictorico. IMO, what you are trying to determine is the minimum exposure to print through the base fog (pictorico in your case), plus a little bit more. :) Also, if you use Ron Reeder's wedge and print until the first two steps MERGE, that means any shadow values greater than 95% in your digital image will print pure black. This may be OK, but I'm just pointing out that you could lose some dark shadow details this way.

Finally, depending how your Nuarc is calibrated, your light units may be much different than someone else with the same machine. So, don't base your exposure times on what someone else is using - they may be VERY different.

[Don7x17]

hello everyone,

very frustrating here..

spent 2 nights just try to figure out what will be the base exposure for my nuarc 261k.

I didn't try to calibrate the integrator, and the bulb seems fine...

now, after last night's intensive work, i think my base value seems sit between 150-300unit.

so here is what i did, i cover up 5/6 of the strip and only exposed the first 1/6 @50units, then moved the card board another 1/6, gave another 50unit exposure..
in such a manner, 50/50/50/50/50/100(so the final is 100/150/200/250/300/350 ), the last one i removed the whole card board, gave the whole strip a 100 unit. it turned out as showing on the attached pic(it is the left part pic).
then right after this strip, I did another one, as showing on the right part of the pic. this one is @ 175/200/225/250/275/300.

the result is very confusing, as I was expecting a finer scale on the 2nd test strip(right hand side)

I have been keep doing this for 2 nights and still get nothing and of course, without a firm base exposure, I can go nowhere!


Thanks


Andrew

Andrew - your test strips are showing far too much exposure for the basic 100 units -- it should be light. Looks like full exposure as the 100 units nearly merges into the 150 units, etc etc.

You either are drying in an area with something exposing (flourescents even just turned off), or perhaps you have bad ferric oxalate (already converted to ferrous)? Try a portion that is coated but not exposed -- does it print/develop out anything other than paper white?

Try fresh ferric oxallate.

And I am in agreement with all the comments on using a step tablet - whether a purchased stoufers, a PDN version, or your own generated version. So much easier and a single exposure rather than multiple cumulative.

and lapping the stoufers or PDN step tablet over the edge of the clear Pictorico will solve the problem that Kerik brings up.

Best to you
Don

[Andrew ren]

Paul,

i am using arches too, and those images on my site are just digi files, not analogue. also I got the QTR, and print from a 3800.

Kerik,

yes, I will start from scratch again in a moment.

Don,

the 100 units exposure is very strong to me too, I will develop a unexposed strip too see if my envirment is clear.

ok, here is what I got this afternoon:

1. the "nipple" on lamp was pointing down, I correct that.
2. i wired a seperate circuit dedicated for that nuarc, powered it on, read the circuit, 0.01amp, what?! then plugin my hairdryer in the same plug, the dryer itself drains 13amps!my first action was jumping out of the basement and put myself on a pair of heavy duty rubbersole boots. i don't want to shock myself! the nuarc must be wired wrong!
then I got down and crack open the top of nuarc, check all the wiring there, everything is fine, input #7 and output wire #13 are all correctly attached. next I open the plug that came with the nuarc, hell! crosswiring everywhere! neutral is on black, black is on ground, and ground is on neutral, I read 24 amps on the ground. I am glad I had a strong ground copper connect @ my basement, otherwise I will have a FUZZY pee into the toliet.
....

ok time for back into the basement. will keep you guys in the loop...

Again, Thanks Paul, you are so kind! and kerik/Don. Thanks!

Andrew

[PViapiano]

Kerik...I think I see what Andrew is trying to do now, it just didn't sink in until now or maybe after I read your post a light bulb went off.

Arentz does the "first two steps merging" for film negs, but I see the usefulness of matching the 0% substrate wedge with the uncovered coating next to it.

Thanks for pointing this out...

[Andrew ren]

ok, updates,

last night before I restarted the test, I did some time-counting to make sure the integrator on the nuarc works.
here is how I did,
Start the nuarc from cold, dial in 120units, then counter down from 30units to 0.
then let it cold down for 2mins exactly, then start from 120, count from 30units to 0 agian.
....

repeat precisely for 5 times.
the result is:
1'18"
1'19"
1'19"
1'23"
1'29"

seems fine to me.
----
Then I started the exposure, guess what?

1st test strip I did as Kerik suggested: 50-100-200-400-600
I can tell the difference @50units and 1oounits, slightly slightly darker @200, and barely see the difference uowards. but the area covered by pictorico seems darker than the uncovered area?! how did that happen?

2nd test, 100-200-300-400. the 100 is almost as black as the uncovered area, might slightly lighter.then the 200-300-400 looks almost same and ALL darker than the uncover area!

hmm, to me the nuarc is fine. and I guarantee that it is on its own dedicated circuit.
oh, and also I did the unexposed strip as Don suggested, its turned out almost paper white, might be a tint of light yellow, which I think its not been cleared(EDTA) enough...

Might be the humidity? last night my meter says 68%RH. the night before its @ high 50%s too..

and the sensitizer is pretty fresh though, I ordered them from B&S July..


Andrew

[clay harmon]

One reason that the uncovered area is lighter is that it is receiving too much exposure and is actually solarizing. Single coated palladium is particularly susceptible to solarization, where after some point increasing exposure yields progressively less print density. If this is the case, the pictorico is holding back enough light even at 400 units to prevent it. But that is a stretch.

Another possibility is that the uncovered area is toward the edge of your coated area on the paper, and it doesn't have as much sensitizer as the area under the Pictorico.

[Kerik Kouklis]

I would agree with Clay's assessment. Try a heavier coat, or try adding a little bit of platinum in your mix. But, it sounds like your standard exposure time is going to be between 200 and 300 units?

Unrelated to the exposure issue - you mention EDTA as your clearing agent. If you're using that by itself, you will not get complete clearing on many papers. You need to add sodium sulfite or use Kodak Hypoclear. EDTA alone is a NOT a good clearing agent for pt/pd. I use one bath of 2% citric acid followed by 2 baths of hypoclear.

[Andrew ren]

Clay, that make sense, seems the metal are building a shiny layer on top after over over expose, sort of brownish.

Kerik, I am using mix of pd and pt, so, I might increase the percentage of the pt then, is the pt going to help prevent the solarization, at least sort of?

yes, I use EDTA as first batch and another hypo cleaning, each for 15mins.. or do 3 cleanings with shorter time.

BTW, i send an email to you, Kerik.

Thanks


Andrew

[Andrew ren]

ok, did 2 stripes again tonight.

got almost the same result between these two. very repeatable, which is a good thing.

all i did was pre-coat a sheet, and left in the dark for a day, and seems worked that way.

exposure is:

100-175-250-300 units on my nuarc.

I think I got it.

Thanks everyone!

Best,

Andrew

[Don7x17]

Unrelated to the exposure issue - you mention EDTA as your clearing agent. If you're using that by itself, you will not get complete clearing on many papers. You need to add sodium sulfite or use Kodak Hypoclear. EDTA alone is a NOT a good clearing agent for pt/pd. I use one bath of 2% citric acid followed by 2 baths of hypoclear.

Kerik

There are two commonly available forms of EDTA -- Tetra Sodium EDTA and Disodium EDTA. They differ in the pH when mixed with water. You will find that Disodium EDTA as a first clearing bath will make clearing easier with the difficult to clear papers, like Platine. Tetra-Sodium, on the other hand, seems to have difficulty in clearing papers when used by itself (three successive baths), or as a first bath followed by two baths of Kodak HCA.

So if you are choosing EDTA -- you will have better clearing with the disodium variety.

Citric acid works fine -- if you are short of supplies you can always used Seven-Up.

regards
Don

[clay harmon]

Any post development step that immerses the print in a solution that is basic (pH over 7) prior to complete clearing will cause problems because it will convert some of the unused ferric oxalate into an insoluble compound that can be almost impossible to clear. Where I live, even the tap water in summer is pH 8, so doing the often-recommended step of a water rinse before any of the clearing trays is a recipe for permanently stained prints. Which is why tetra-sodium EDTA by itself as a clearing agent is not only ineffective, it is actually harmful to your print. The Di-sodium variety works fine, as you note, because the pH is below 7 (around 4 or 5, if memory serves). But citric also works well, and is cheaper.

[Andrew ren]

Thanks Clay.

Andrew

[Kerik Kouklis]

Kerik

There are two commonly available forms of EDTA -- Tetra Sodium EDTA and Disodium EDTA. They differ in the pH when mixed with water. You will find that Disodium EDTA as a first clearing bath will make clearing easier with the difficult to clear papers, like Platine. Tetra-Sodium, on the other hand, seems to have difficulty in clearing papers when used by itself (three successive baths), or as a first bath followed by two baths of Kodak HCA.

So if you are choosing EDTA -- you will have better clearing with the disodium variety.

Citric acid works fine -- if you are short of supplies you can always used Seven-Up.

regards
Don

Yes Don7x17, I know all of this. However, the EDTA that B&S sells as a clearing agent and is used widely by people beginning the pt/pd process is the tetra-sodium variety.

Di-sodium EDTA is $20 a pound and citric acid is $6 a pound at Artcraft (and much cheaper in bulk).

Citric followed by hypoclear is a very effective and economical way to clear pt/pd prints, which is why I recommend it. OK?

Kerik

[Don7x17]

Yes Don7x17, I know all of this. However, the EDTA that B&S sells as a clearing agent and is used widely by people beginning the pt/pd process is the tetra-sodium variety.

Di-sodium EDTA is $20 a pound and citric acid is $6 a pound at Artcraft (and much cheaper in bulk).

Citric followed by hypoclear is a very effective and economical way to clear pt/pd prints, which is why I recommend it. OK?

Kerik

OK, it looks like your budget must be extremely tight.

The clearing solutions don't use much of either Citric Acid or Tetra Sodium EDTA. So the cost difference in the clear doesn't amount to much (3x more of virtually nothing).

I am far more concerned about ending up with a yellow tint that can't be subsequently cleared after drying - the Pt/Pd costs far more for one and portion bad 12x20 print than the difference in the cost in a pound of citric vs TS EDTA.

I've had far better results with TS EDTA than Citric as first clearing bath. YMMV.

[Don7x17]

Any post development step that immerses the print in a solution that is basic (pH over 7) prior to complete clearing will cause problems because it will convert some of the unused ferric oxalate into an insoluble compound that can be almost impossible to clear. Where I live, even the tap water in summer is pH 8, so doing the often-recommended step of a water rinse before any of the clearing trays is a recipe for permanently stained prints. Which is why tetra-sodium EDTA by itself as a clearing agent is not only ineffective, it is actually harmful to your print. The Di-sodium variety works fine, as you note, because the pH is below 7 (around 4 or 5, if memory serves). But citric also works well, and is cheaper.

Yes, exactly why Disodium EDTA as first bath clears better than Tetra Sodium EDTA or even Citric Acid. I follow this with HCA and TS EDTA (using up the old stock!)

[sanking]

OK, it looks like your budget must be extremely tight.

The clearing solutions don't use much of either Citric Acid or Tetra Sodium EDTA. So the cost difference in the clear doesn't amount to much (3x more of virtually nothing).

I am far more concerned about ending up with a yellow tint that can't be subsequently cleared after drying - the Pt/Pd costs far more for one and portion bad 12x20 print than the difference in the cost in a pound of citric vs TS EDTA.

I've had far better results with TS EDTA than Citric as first clearing bath. YMMV.


Well, I for one have always gotten much better clearing with citric acid than with Tetra Sodium EDTA and if the cost of the citric acid is 1/4 that of the EDTA I am happy to pocket the change.

My experience with the iron processes is that yellowing that can not be cleared is due to, 1) old ferric oxalate or 2) developer that has changed from acid to base. With fresh ferric oxalate and a fresh developer that is clearly acidic (below PH 6 or so) I have never had any problem clearing with citric acid. I don't wash the print between the developer and the first clearing bath because if the tap water is alkaline it will set the iron into the paper and you will never be able to clear it, even with hydrochloric acid. So the key is not to clear the yellow stain, but to keep it from forming in the first place.

Sandy King

[Kerik Kouklis]

OK, it looks like your budget must be extremely tight.

blah, blah, blah...

YMMV.

Really Don? Since you brought up mileage, when I'm driving down the street and I need gas, I look over at the Chevron and see you filling up your Yugo for $3.50 a gallon, I choose to stop at the Arco and get gas for $2.99. It's not because I can't afford the Chevron gas, it's because I'm not a dumbass.

To put a point on it, citric acid works just as well as di-EDTA and I have zero risk of ruining a print due inadequate clearing. My time is way more valuable to me than the materials I use.

I'm just trying to help out someone getting started and pointing out what for me are the most economical and EFFECTIVE methods to getting the job done.

BTW, could you post your website. I'd love to see some of your work. Have a nice day everyone!

[Don7x17]

Really Don? Since you brought up mileage, when I'm driving down the street and I need gas, I look over at the Chevron and see you filling up your Yugo for $3.50 a gallon, I choose to stop at the Arco and get gas for $2.99. It's not because I can't afford the Chevron gas, it's because I'm not a dumbass.

To put a point on it, citric acid works just as well as di-EDTA and I have zero risk of ruining a print due inadequate clearing. My time is way more valuable to me than the materials I use.

I'm just trying to help out someone getting started and pointing out what for me are the most economical and EFFECTIVE methods to getting the job done.

BTW, could you post your website. I'd love to see some of your work. Have a nice day everyone!

Kerik - your character, or lack of it, is showing in this post. I'm sure you'll regret it later.

Tsk tsk - I'm not the cheap one driving a yugo and I am certainly not the dumbass you've called me.

Mike Ware, the expert in the chemistry of this process, seems to agree with disodium as a first bath as well....

I don't need to validate my work by having you review it. I like your work, by the way.

have a nice day all

[David Eisenlord (Ike)]

Its not about validating your work, its about your credibility. If you showed your work, your teaching schedule, and your history of exhibition, it would be easier to access the credibility and experience behind your statements.

[Don7x17]

Its not about validating your work, its about your credibility. If you showed your work, your teaching schedule, and your history of exhibition, if would be easier to access the credibility and experience behind of your statements.

And your credentials?

[Kerik Kouklis]

Your character is revealed as well. But, strangely, not your identity. Me? no regrets. Not today or not later. And I've got nothing to hide.

Hmmm... why do you think your work needs to be validated? I didn't bring that up. I'm not here to validate yours or anyone else's work. I'm just curious to see what you do.

[Don7x17]

Your character is revealed as well. But, strangely, not your identity. Me? no regrets. Not today or not later. And I've got nothing to hide.

Hmmm... why do you think your work needs to be validated? I didn't bring that up. I'm not here to validate yours or anyone else's work. I'm just curious to see what you do.

You must have missed the PM I sent asking you to take this offline. Oh, I see you responded to that one too

Lets end this

[David Eisenlord (Ike)]

And your credentials

I'm not hiding, my name is David J. Eisenlord and my website is www.davideisenlord.com

[Don7x17]

I'm not hiding, my name is David J. Eisenlord and my website is www.davideisenlord.com

Sorry, I don't have a website. Guess I should one of these days. I'm Don Nelson, not hiding. Arentz knows me since 1993 and my work. Excellent images on your site - I'm particularly enamored with the tree on the point you use as intro for the section

And your credits indicate you coteach with Kerik. Excellent!

[Andrew ren]

excellent!

everyone.

Andrew

[David Eisenlord (Ike)]

Thanks Don.
Dave