New Darkroom for Pd/Na2 printing, low humidity

[Minas Stratigos]

I recently moved my darkroom, unfortunately my humidity is low, 30%

what is the best tip you can give me to pre-coating humidification and pre-exposure humidification. I tried the method of the tray full of water with the paper taped at a cover but it only helped a little.

thanks

Minas

 

[dasBlute]

I'd try a room humidifier. I also heat my water bath tray with a 'sous vide' which itself maintains a bit of humity and heat,
so maybe not so useful for you except in the cooler months... I keep a humidity meter in the darkroom and keep it at 60% or higher [!]
when printing pt/pd, I also use a "moisture meter, pin type' which checks the paper, about 15% seems to be a good place to start for me...

hope you find something that works, it's a marvelous process...

 

[Mainecoonmaniac]

You don't have to humidify your whole darkroom. I built a humidification chamber (a plastic box with a bit of water at the bottom) and used a cheap hydrometer to know the humidity in the box I got on ebay.

https://www.ebay.com/itm/Gauge-Blac...818268&hash=item2cd7f64f78:g:d5UAAOSwdjhbTt2u

 

[Minas Stratigos]

You don't have to humidify your whole darkroom. I built a humidification chamber (a plastic box with a bit of water at the bottom) and used a cheap hydrometer to know the humidity in the box I got on ebay.

https://www.ebay.com/itm/Gauge-Blac...818268&hash=item2cd7f64f78:g:d5UAAOSwdjhbTt2u

I tried with a photo tray full of water and a lid, i taped the paper on lid and left it for 15 minutes but the imrovement was minor. how long do you leave your paper pre-coating in the chamber and how long pre-exposure?

 

[Alan9940]

Like Tom, I built my own humdification box out of a large plastic storage container w/lid. I built a rack out plastic plumbing pipe that fits inside. I cut a hole in the bottom of the box and run a teardrop-style humidifier up into the box. When up & running, humidity runs at about 80%. I humdify only pre-exposure for about 5-10 mins, depending on the paper. I use plastic sheeting behind the paper, when in the print frame, to minimize escape of moisture. This setup has worked well for me for years and I live in the desert (think VERY dry!)

 

[Minas Stratigos]

Like Tom, I built my own humdification box out of a large plastic storage container w/lid. I built a rack out plastic plumbing pipe that fits inside. I cut a hole in the bottom of the box and run a teardrop-style humidifier up into the box. When up & running, humidity runs at about 80%. I humdify only pre-exposure for about 5-10 mins, depending on the paper. I use plastic sheeting behind the paper, when in the print frame, to minimize escape of moisture. This setup has worked well for me for years and I live in the desert (think VERY dry!)

Thanks Alan, i will try to work with a sealed storage container and see what happens, i am very much interested in the consistency of the results

 

[Mainecoonmaniac]

I tried with a photo tray full of water and a lid, i taped the paper on lid and left it for 15 minutes but the imrovement was minor. how long do you leave your paper pre-coating in the chamber and how long pre-exposure?

What I like to do is to put the number of sheets in the humidification chamber I plan to use in a session. I pull a sheet out before coating. I also tried to use a clothes steamer I got from the thrift store which works too. It's a pain because I have to steam each sheet before coating.

 

[Minas Stratigos]

I borrowed a humidifier and used it to reach between 52%-60%, I stored the papers in the room for a couple of hours before coating. Coating feels much better now, I also do use 2 drops of Tween on Hahnemuhle platinum rag but now I see blotches and mottling at the print.

I guess I didn't dry the paper enough after coating before exposure, I will try again tonight.

 

[nmp]

I borrowed a humidifier and used it to reach between 52%-60%, I stored the papers in the room for a couple of hours before coating. Coating feels much better now, I also do use 2 drops of Tween on Hahnemuhle platinum rag but now I see blotches and mottling at the print.

I guess I didn't dry the paper enough after coating before exposure, I will try again tonight.

A characteristic of Tween, or for that matter any surfactant, is that if you use more than a certain amount, bad stuff can happen, typically spots, blotches, etc (something to do with critical micelle concentration.) I would try and use less (or more diluted solution) if the problem persists.

 

[Bob Carnie]

A room humidifier is essential for places that see low humidity, from Nov to April I need to humidify the dark/dim room to get the humidity over 45% , if not I cannot print plain and simple, a small price to pay to
keep consistent results.

 

[dpurdy]

I have for years done something that will make people cringe, wrinkle their nose and shake their heads.. I use steam. I use a square electric pan, deeper than a skillet, about 11 inches square, a standard size, I fill it up with water and turn it on high enough that it creates lots of steam when I take off the lid. Then I steam a piece of paper both sides, moving it around like using a buffing machine, until the paper is pretty limp. Then I let it set for a few minutes, at least 5, and then put it under the light.. I only steam after coating and the coating is dry. Maybe there was a learning curve somewhere along the line, I don't know, but I am very methodical and I get very consistent results. Smooth prints and deep blacks.

 

[Bob Carnie]

I have for years done something that will make people cringe, wrinkle their nose and shake their heads.. I use steam. I use a square electric pan, deeper than a skillet, about 11 inches square, a standard size, I fill it up with water and turn it on high enough that it creates lots of steam when I take off the lid. Then I steam a piece of paper both sides, moving it around like using a buffing machine, until the paper is pretty limp. Then I let it set for a few minutes, at least 5, and then put it under the light.. I only steam after coating and the coating is dry. Maybe there was a learning curve somewhere along the line, I don't know, but I am very methodical and I get very consistent results. Smooth prints and deep blacks.

Not crazy at all, I used this method when I was doing dye retouching of prints , and I plan to try this for retouching of pigment prints as well to soak the pigment into the paper.

 

[nmp]

I have for years done something that will make people cringe, wrinkle their nose and shake their heads.. I use steam. I use a square electric pan, deeper than a skillet, about 11 inches square, a standard size, I fill it up with water and turn it on high enough that it creates lots of steam when I take off the lid. Then I steam a piece of paper both sides, moving it around like using a buffing machine, until the paper is pretty limp. Then I let it set for a few minutes, at least 5, and then put it under the light.. I only steam after coating and the coating is dry. Maybe there was a learning curve somewhere along the line, I don't know, but I am very methodical and I get very consistent results. Smooth prints and deep blacks.

This is standard for ziatype or POP Pt/Pd, as I understand.

 

[Minas Stratigos]

oing dye retouching of prints , and I plan to try this for retouching of pigment prints as well to soak the pigment into the paper.

I have for years done something that will make people cringe, wrinkle their nose and shake their heads.. I use steam. I use a square electric pan, deeper than a skillet, about 11 inches square, a standard size, I fill it up with water and turn it on high enough that it creates lots of steam when I take off the lid. Then I steam a piece of paper both sides, moving it around like using a buffing machine, until the paper is pretty limp. Then I let it set for a few minutes, at least 5, and then put it under the light.. I only steam after coating and the coating is dry. Maybe there was a learning curve somewhere along the line, I don't know, but I am very methodical and I get very consistent results. Smooth prints and deep blacks.

Interesting, I wonder how to try it without fogging the paper... my darkroom is too compact for a kettle/steamer.

 

[DennyS]

Interesting, I wonder how to try it without fogging the paper... my darkroom is too compact for a kettle/steamer.

I use a cold mist humidifier the same way, it's compact and effective.

 

[Minas Stratigos]

I use a cold mist humidifier the same way, it's compact and effective.

Finally after trying various options i abandoned the idea of room humidifier, it makes the small room a sauna. I took a plastic container, added self adhesive foam insulation to the lid and a sponge with water inside. Takes humidity to 80% when closed for 1 hour so i guess i can use this for pre-coating and pre-exposure humidification.

 

[Alan9940]

Finally after trying various options i abandoned the idea of room humidifier, it makes the small room a sauna. I took a plastic container, added self adhesive foam insulation to the lid and a sponge with water inside. Takes humidity to 80% when closed for 1 hour so i guess i can use this for pre-coating and pre-exposure humidification.

Sounds like you may have found a solution! Further printing will tell the tale. One thing I forgot to mention that might help; when you pull the paper from your humidification chamber, it should feel "cold and limp." This subjective judgement has always worked for me to know that my paper probably has the correct amount of dampness.

 

[Minas Stratigos]

Update: I tried many different options, eg. pre-humidify at 75% for hours, coat, dry to touch, re-humidify for 10 mins. There is plenty of grain even if i reduce Na2 or remove tween20 completely. I need to do more tests but looks like what will work for me is to find a way to just coat and then dry the appropriate amount of time and expose.

 

[Minas Stratigos]

Question & Update/2: with just one drop of Na2 5% (16/FO/16Pd/1 Na2@5%) I get awful grain, this can be humidity right, Is the paper too humid or not humid enough? The same chems and mix and paper have been used two weeks ago in my previous darkroom where RH was 70% without grain. Paper is Hahnemuhle Platinum Rag.

Method followed:
Humidifying chamber 15mins @ 70%
Coat and natural dry 5 mins, a quick blowdry in medium heat after for a minute or so, paper feels dry
Humidifying chamber 8mins @ 70%

Exposure for 27mins

 

[Alan9940]

Minas,

You certainly are running into just about every issue a pt/pd printer can have... White specks or "grain" are really tough to nail down a cause. Paper can be the issue, but you're using the same paper; I'm assuming it's all from the same batch? I'm assuming, too, that your brushing technique is consistent. You could try soaking the paper in Oxalic acid. Do you have a different paper to try to see if same results? Sorry, but pt/pd printing can be a continual process of experimentation and resolving issues because our supplies, like paper, for example, is not necessarily consistent. When I need paper, I buy as much as I can from one batch and test it. Manufacturers change, raw materials change, it's a moving target!

 

[nmp]

Could it be that 15 minutes is not enough to equilibrate the paper? I am assuming you had the paper stored at high humidity all the time at your old place which might have been needed to be saturated with water. Perhaps leaving the paper overnight or longer in the humidity box may make a difference....grasping at straws.

 

[Minas Stratigos]

Minas,

You certainly are running into just about every issue a pt/pd printer can have... White specks or "grain" are really tough to nail down a cause. Paper can be the issue, but you're using the same paper; I'm assuming it's all from the same batch? I'm assuming, too, that your brushing technique is consistent. You could try soaking the paper in Oxalic acid. Do you have a different paper to try to see if same results? Sorry, but pt/pd printing can be a continual process of experimentation and resolving issues because our supplies, like paper, for example, is not necessarily consistent. When I need paper, I buy as much as I can from one batch and test it. Manufacturers change, raw materials change, it's a moving target!

I certainly enjoy the learning curve
I tried two different boxes of Hahnemuhle (8x10 & 11x15) and it is the same i used two weeks ago, I also have 50 8x10 sheets of COT320 on the way and I suspect it will be much easier as i consider it a forgiving paper. I cannot be sure of my coating technique, of course I am trying to do the same strokes each time but maybe I am not, its the time that I am not sure of anything. In general I brush quite some time since there is plenty of extra mix usually

After my post earlier today I did another test, printed a 51step wedge on 2x16in coverage 5FO/5Pd/2Na2@1% and I got a nice smooth non grainy print following exactly the same method, same paper, just flat at midtones, need to fix the curve, but Dmax was very low 1.18, phew (apologies for the bad image)

 

[Minas Stratigos]

Could it be that 15 minutes is not enough to equilibrate the paper? I am assuming you had the paper stored at high humidity all the time at your old place which might have been needed to be saturated with water. Perhaps leaving the paper overnight or longer in the humidity box may make a difference....grasping at straws.

Yes you are right, paper was stored at old place in 65%-75%

I tried also 24 hours in the humidity box... same results. can it be FO? something happened to it ? I am only 6 months in this so my experience with Fo is limited. i see crystals at the lid lately :-0 in general my chemistry box is stored now at 30 Celcius while before ist was at 22 Celcius

 

[Alan9940]

Minas,

6 months on the FO is about its max lifespan as far as I'm concerned; especially, at your higher storage temp. I never use FO beyond 6 months. I buy it in powder form and mix when needed. The metals, of course, are all fine.

 

[nmp]

Yes you are right, paper was stored at old place in 65%-75%

I tried also 24 hours in the humidity box... same results. can it be FO? something happened to it ? I am only 6 months in this so my experience with Fo is limited. i see crystals at the lid lately :-0 in general my chemistry box is stored now at 30 Celcius while before ist was at 22 Celcius

You are one step ahead of me...

I will defer to the more experienced folks here about FO problems. I store my chemicals in a fridge. Don't know if that is helpful or detrimental to FO. I have a decade old solution that seems to be still "good," no ppts or significant ferrous content, although I have not done any real prints with it in a long time so can't say whether or not it will have coating problems like yours if I try.

Good luck in your sleuthing....

:Niranjan.