paper humidification with Ziatype

Mainecoonmaniac · Dec 5, 2014

I'm sure this question is also applicable to platinum and palladium printing too, but I found a used close steamer that I plan to humidify my Ziatype paper before printing. I plan to coat the paper then humidify the paper before I make the contact print. May I just steam the back of the paper, the opposite of the coated side? Or does the emulsion has to be humidified too? I'm afraid if I steam the emulsion side, the emulsion will too wet and my neg will get wrecked. Thanks in advance!

Ian Leake · Dec 6, 2014

The purpose of humidification is to increase the moisture content of the sensitiser not the paper. The easiest way to do this is by taping the dried, coated paper to a sheet of glass and then hanging it face down over a tray of water for a few minutes (more time = more humidity = greater Dmax).

If you have an effective coating and drying technique then you can get a good Ziatype Dmax without humidification. You may find a small amount of glycerin in your coating helps here. I found 1 drop of glycerin for a 10x8 is sufficient to capture sufficient moisture to achieve a good Dmax (with effective drying).

The ideal sensitiser humidity for all the POP Pt/Pd processes is as high as you can reliably get without sticking to the negative during a long exposure. Having lost my fair share of negatives this way, I suggest that you use spare negatives when experimenting with this.

Mainecoonmaniac · Dec 6, 2014

Hi Ian. You made my light bulb go on. Yes. I've lost negs too. The ink jet negs I don't care too much, but original negs are more precious. I've used acetate to protect my negs and it works well.

pschwart · Dec 6, 2014

- 2 mil polypropylene bags are perfect for storing and exposing negatives and they come in a large
variety of sizes
- ziatypes generally don't need humidification beyond coating unless your environment is
extremely low humidity - just don't let it get bone dry before exposing. I blow dry papers for about
30-45 seconds and expose when the surface is no longer cool to the touch.
- a vapor barrier behind the paper during exposure will help retain moisture -- especially important
for long exposures and/or hot lights

Mainecoonmaniac · Dec 6, 2014

Thanks for all the advice. I have a habit of batch coating my paper in the dry summer. The next day, the emulsion dries out and I get flat prints. I get good results from freshly coated paper. I printed this morning. Here's pic

Ian Leake · Dec 7, 2014

Yes, if you are drying the sensitiser overnight then it's likely to be far too dry to print well - although this would depend a bit upon atmospheric humidity. A humidity tank would ensure even humidity. Try 20 minutes over water as a start - with an unimportant negative.

A darkroom tray is fit for purpose, and allows you to easily test the method, but it is not fully controllable because the thermometer notch allows air to circulate within. A cat litter tray (or something similar) allows you finer control of humidity because it has a better seal with the lid. You can then use saturated solutions of various things (e.g. household salt) to fine control the humidity. Mike Ware has some good stuff about this on his website in his Pt/Pd methods.

pschwart · Dec 7, 2014

Ian Leake said:
A humidity tank would ensure even humidity. Try 20 minutes over water as a start - with an unimportant negative.

Where's the advantage when you can coat a piece of paper and be ready to print in a couple of minutes?

Loris Medici · Dec 7, 2014

Hi all,

Timing the drying phase (dependent on conditions; 30 minutes min. - 60 minutex max. ...) and adding some glycerin to the coating solution (again, amnt. dependent on conditions; usually 1 or 2 drops per ml of coating solution is enough - when you need it...) works for me. If you need very fine control over color (I don't; I go for neutral results - don't print warm...) and/or your conditions are extreme (very cold/hot - very dry/humid), then you may opt for a humidification chamber a la Mike Ware. The time between coatings (min. 30 - max 60 mins.) is used for the exposure and processing stages; therefore there's no lost time actually. I don't like to force dry (hair dryer or any other kind of hot air supply) or humidify (e.g. vapor from hot water, ultrasonic humidifier...) the paper, causes inconsistencies for me - especially so when you use a vacuum frame and don't have an easy way of controlling exposure, such as when using a split back contact printing frame.

BTW, you have coating and clearing problems in that test print; I see some grainy and mottled areas (bad absorption and/or too thick coatings?) and a yellow base in highlights. How do you clear the prints?

Regards,
Loris.

Mainecoonmaniac · Dec 8, 2014

Thanks again for your help

Loris Medici said:
BTW, you have coating and clearing problems in that test print; I see some grainy and mottled areas (bad absorption and/or too thick coatings?) and a yellow base in highlights. How do you clear the prints?

Thanks for your advice. I put them in my note book and I'll refer to them. Advice too good to forget. The mottled print is from the emulsion not fully dried and I did clear the print in citric acid. I think I used too much sodium tungstate to warm up the print. I made another print with less and I like the color better. I'm still learning how to make Ziatypes and I'm learning through mostly from APUG and of course my mistakes .

Gadfly_71 · Dec 9, 2014

There are couple of options if you live where the humidity is low;

1. Run a humidifier in your coating area/studio/darkroom to bring the ambient humidity up, especially on very dry days. I normally run a small ultrasonic type in my darkroom set to low or medium. I turn it on about an hour before I start working and it really helps with kallitypes and vandykes (I'm sure it'll help with ziatypes and PT/PD as well).

2. I sometimes have an issue with the sensitizer drying as I coat. If this happens, I wet a clean brush with distilled water and pre-dampen the paper. I let the paper dry slightly before coating.

Peter Schrager · Apr 14, 2018

I'm about to begin Ziatype. I watched a video where the person wet the back of the paper; no coated side with a brush
any thoughts on this?

Ian Leake · Apr 14, 2018

Peter Schrager said:
I'm about to begin Ziatype. I watched a video where the person wet the back of the paper; no coated side with a brush
any thoughts on this?

You need to control the water content (humidity) of the sensitiser. Water applied to the back of the paper would presumably increase sensitiser humidity once it had soaked through the paper, but this must be hard to control; presumably also highly dependent on the specific paper used. The best way to control sensitiser humidity is to let the paper rest in a known atmospheric humidity for some time.

Peter Schrager · Apr 14, 2018

Ok Ian I was worried because we have low humidity but looking at the weather for next week should be in 40-55% range...
That work should work well??
Dana at bostick and Sullivan also advised me to use 1 drop tween...good/no good??
Thanks in advance!!
Peter

Ian Leake · Apr 14, 2018

Peter Schrager said:
Ok Ian I was worried because we have low humidity but looking at the weather for next week should be in 40-55% range...
That work should work well??

Give it a try It's easy to boost sensitiser humidity by sticking the dried paper to a board and suspending it over a darkroom tray of water for 5-10 minutes. I'd strongly recommend that you record everything you can about how you prepare/dry the sensitiser: paper, quantity of sensitiser, ambient temperature, ambient humidity, drying times, any forced drying you do (e.g. hair dryer), etc. All of these affect the sensitiser humidity.

Peter Schrager said:
Dana at bostick and Sullivan also advised me to use 1 drop tween...good/no good??

The amount of TWEEN20 you need, if any, depends very much on the paper you're using. I use one drop of 25% TWEEN20 for an 8x10 on Rives BFK, which is already an absorbent paper. You may need more for a watercolour paper.

Peter Schrager · Apr 14, 2018

Thank you ian!! Will report back later this week
I'm already familiar with pt/pd but since I don't have a real darkroom I can do the processing outside (except coating)
Thanks again !!!
Peter

Peter Schrager · Apr 14, 2018

For paper I have the good cranes from years ago..its very smooth so may not need tween

paper humidification with Ziatype

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