Drying Coated Paper

[Annie]

Drying...
In the books by Arentz & James they discuss using various set-ups of hairdryers for drying Pt/Pd coated paper. James warns about ferric oxalate that becomes airborne during blow-drying and recommends wearing a mask during this part of the procedure. I personally do not want to give this toxic dust the opportunity to flutter about in my darkroom so I would like to air dry my paper, however, neither author even mentions the possibility. Am I missing something? Is the heat of the dryer intrinsic to the process or can the paper be put in racks for drying? When the paper is dry can it be stacked with interleaving or is this a potential source for contamination?

Humidity...
I have a psychrometer so I can measure the humidity of my darkroom. Just curious about the ideal humidity level and if others are recording this data as part of their documentation for each print... or is this considered to be waaaaaay too obsessive?

Cheers Annie

 

[clay]

When I built my darkroom, I put in a paper drying cabinet that basically amounts to a slot for a 28" box fan (cheap at any Walmart type of place) that is mounted to allow the air to be directed at a shelf about 8 inches below that has a window screen on which to lay the just-coated paper. I put a blackout fabric curtain in place of a door, and it gives me a nice light-tight drying cabinet. My darkroom humidity varies between 45 to 60% normally, and I find that most papers dry within 10 minutes. I don't have to worry about blowing nasty stuff around the darkoom, and it allows me to coat another sheet while the first one is drying.

As an aside, the test for whether a sheet of paper is dried or not is to touch the inside of your wrist against the uncoated side of the paper. If it feels cooler to the touch than ambient temperature, it needs to dry a bit longer. Anyone familiar with testing the temperature of baby bottles will realize why this works so well.

 

[philsweeney]

I have similiar questions for the related Kallitype process. Since it is recommended the coated paper not be dried with heat, can the sheets after drying be stacked? And after they are coated and dried, how soon should they be used? I would probably prefer to make 10-15 sheets in advance. To reiterate Annie's question can the pt/pd papers be air dried and stacked?

 

[clay]

Sure, you can air dry and stack them once they are dry. I would take a little care to make sure you don't abrade the coating though. I generally don't like to coat much more than an hour or two in advance of use though. I generally get in a 'groove' where I will be coating, printing and processing simultaneously, all the while balancing a beach ball on my nose and playing a trumpet.

 

[CraigK]

One word of caution regarding drying hand coated paper.:

I once helped a student who could not figure our why his prints had a sort of blotchy look to the highlights. He tried everything to make them go away....change dev's, coating rod, brush, different mix etc. etc.

I was finally able to pinpoint the problem when I saw him coat and then dry a piece of paper. As soon as he put down the rod or the brush he would blast the paper with the hair dryer! Not a good idea. The solutions need a bit of time to settle into the paper. How much time is dependant on the humidity, type of paper and solutions.

Things smoothed out condiderably once he let the paper "rest" a minute or three after coating and before drying with the hair dryer. I aslo suggested that he set the hair dryer to low instead of Max Power.

 

[clay]

I don't like to use hair dryers at all. On most of the papers I typically use, I will just let them dry under a window fan set to 'low'. The only exception I make to this is when I use papers that seem too absorbent, and you need to dry the coating before it sinks too deeply into the paper fibers. In general papers that sink in the wash fall into this absorbent category, while papers that float in the wash do best if you just let them dry at ambient temperature under a little moving air.