Platinum printing demo - my new video!

[Eric Biggerstaff]

Nice video Paul.

What LED strips are you using?

I posted detailed instructions on making an LED UV box on the forum a year or so ago. Recently the LED's in my unit shifted color and no long print (this is after I made several hundred prints). I need to replace them and have settled on the a different type of UV LED, but I am curious what you are using and how many prints you have made with the unit.

[Paul Cunningham]

Nice video Paul.
What LED strips are you using?

Hi Eric, thank you for the kind words. And thank you also for the post you referred to, it was very instrumental in my own adoption of platinum palladium.

I'm probably using UV strips very similar to the ones you were using, the type with a waterproof coating. Greg Brophy reports that the shift was due to yellowing of this coating, and if this is the cause, then I will just pull it off when needed. It may leave some adhesive behind, but that doesn't seem like something to worry about. The cost was so nominal that even replacing the LEDs is not a huge issue, even discharge bulbs and black light tubes are consumables.

I'm of course curious to know what you will use as a replacement, but my standard pt/pd print time is 240 seconds. (On a related note, I did buy a used NuArc for large scale prints and exposures are at least 2-3x). Cheers

[tgtaylor]

Reliability and consistency are my issues with the sun. Especially at this time of year in Portland, Oregon. You can't beat the price, as long as you have the patience.

Well if you can't trust it you'd be a fool to print with it. Personally I find it eminently trustworthy and consistent. Initially I was one who wouldn't print unless if was a cloudless day - what would I do if a passing cloud came by??? Then one morning I coated a sheet of paper and timed the drying until the "fog" outside burned off. But the fog was actually heavy cloud cover - no brakes - and the sheet was already coated and the clock was ticking. So I exposed it as normal, shade and finishing it off pointed at the spot where I assumed the sun was hiding. Came out well exposed as if the sun wasn't behind the clouds. Now I don't worry about the clouds after all you can get a sunburn on a cloudy day. It may take a little longer but the actual exposure time is but a fraction of the processing time and I'm not going to pull the print until the exposure is right anyway.

Thomas

[stawastawa]

thomas, with my cyanotype printing I often find hazy cloudy days to be better than sunny days. Probably because of the heat factor and moist paper sometimes buckling.
you say finish of pointed at the sun... do you print by inspection? are your times slightly longer in the clouds?
cheers,

[tgtaylor]

I print by inspection taking several peaks along the way to see how its progressing. You can print totally in the shade or under an overcast sky in which case the exposure time will be greater than in direct sunlight. I time my exposures with a stop watch but I determine how much more exposure to give it during the inspection and keep a check on the time with the watch. Since I do the bulk of the exposure in the open shade, I know when to start checking. Knowing what you are looking for you can then determine when to give it a final blast in direct sunlight. This is the Kallitype of which I am speaking which is a hybrid DOP/POP but I use the same method with other processes. The Cyanotype is a slow printing process so instead of say 6 minutes in the shade maybe 15 or 20 minutes in the shade.

Thomas

[Willie]

How do you guys using sunlight print in the winter? Inside through the windows? Can't see putting a contact printing frame out in the sunlight at 22 below zero.

[stawastawa]

thanks thomas,

Willie, try it and tell what happens!

How do you guys using sunlight print in the winter? Inside through the windows? Can't see putting a contact printing frame out in the sunlight at 22 below zero.

[andreios]

Looks good! One problem with the sun also is that it does not work if you only have time to print during the nights, as I do..

[tgtaylor]

How do you guys using sunlight print in the winter? Inside through the windows? Can't see putting a contact printing frame out in the sunlight at 22 below zero.

Doesn't make any difference how cold it is outside, the UV is still there. You can get a sunburn in the winter too.

One problem with the sun also is that it does not work if you only have time to print during the nights, as I do..

You can print by moonlight too since the moon reflects the suns rays - in fact they make UV/ND eyepiece filters for observing the moon through a telescope or binoculars. Might take a while though - I'd wait for daylight myself.

Thomas

[sanking]

Paul,

Nice video, thanks.

I was very impressed with how neat and clean everything looked, even the chemistry bottles! Big contrast to my work space where carbon pigment solutions seems to find a way to nearly everything in my space.

With regard to UV light sources, hope you get long life from your LEDs. I spent quite a bit of time and money installing the strip LEDs in a large UV light source, hoping to supplement the existing BL tubes to shorten exposure times. And it worked for a while, but after about a year the strips changed color and useful radiation dropped significantly.

As for using the sun to expose alternative processes, works great if you live in the desert southwest and only print in the day. Also nice for POP processes where you can peek to evaluate exposure. But unless one combined the sun with a light integration system I would not recommend the sun for printing pt/pd. This chemistry is just too expensive to leave much latitude in terms of exposure time.

Sandy