is this with pt/pd printing? I don’t have any experience with the process (too expensive for me at the moment) but I’ve heard that shorter exposure times are generally better
Kallitypes. I am toning with platinum but I'm not sure how the toner would matter.
Longer exposure times, especially with lights that produce a significant amount of heat, will have a negative effect on print quality because so many of these alt processes are humidity dependent, and those really long exposure times allow the coated solution to begin to dry out, which impacts contrast and sensitivity. It becomes a vicious cycle - with longer exposure times, you lose contrast and sensitivity, one of the cures for which is longer exposure, which further decreases contrast and sensitivity. And so on. So yes, having powerful, fast LED lights makes your exposure cycle much shorter which benefits your overall print quality.
I just built a UV LED light box, using inexpensive (but well-built) self-contained fixtures from Onforu (Amazon). They dramatically shorten my exposure times from eight minutes to 30 seconds. An unexpected bonus: The prints I am pulling with them also seem to have darker blacks, clearer highlights, and more apparent detail.
I am wondering: Do longer exposure times cause some sort of veiling effect? Or is something else going on here?
(If anyone wants to explore the lights, Google "CTB96UV" -- that should bring up the Amazon listing. The lights come in pairs, each measuring about 5.5x15 inches -- butt the two together and you have a 11x15 UV LED light source for $69. (Add two more for a 15x22 light source for $138.) Each unit is rated at 96 watts. Build quality is good -- anodized aluminum casings and brackets, and a glass cover. I made a stand from a 2x2-foot sheet of ply, supported by 9-inch legs, and mounted the lights on their brackets underneath.)
Sanders McNew
www.flickr.com/sandersnyc
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Sanders - Thank you so much for answering my question, and attaching a photo of your set-up, that makes it very clear...I have been "trolling" the alt photo stuff here on Photrio and have found it very useful as well. I did some cyanotype's last summer and got some OK results ( however interrupted by a house project and am just getting back to it). While the cyanotypes were OK and I learned all the curve/digital negative stuff, I am not that enamored of the blue color.
I have seen some pt/pd prints in museums and was impressed with the tonality and overall look, and I was down in Raleigh and saw some Van Dykes at a gallery that were very impressive as well ( the photography not so much). I am going to start first with some Van Dykes and I have a set of kallitype chemicals as well. I am going to try it after I practice a bit on the Van Dyke process. Ultimately, I plan on doing some toning with the Kallitypes to get then to approach the pt/pd look. I have been gifted a fair amount of rag paper from a retired watercolorist ( my mother in law) who had quite a stash, so I will see how that works and give that a try, at least initially. Bergger COT 320 seems to be the paper of choice for these processes so I will probably end up with some of that as well.
Thanks again for your reply and helpful comments - you live in a beautiful part of the world. I had a photographer friend ( he was a film/darkroom guy) who lived in Asheville for several years and captured some beautiful images from the surrounding area. Unfortunately he left the area....
Regards
Dave Najewicz
David Najewicz Photography
All Images © David Najewicz 2010-2022, all rights reserveddavidnajewiczphotography.tumblr.com
There are a lot of factors in play.
Do Kallitypes create a printed-out image during exposures (seems like most alt processes do....pt/pd and cyanotypes -- even carbon but you can't see it)?
1) Longer exposures allow the printed-out image to have a greater effect than with quick exposures. Since the image forms stronger with more exposure, the printed-out image acts as a printing mask to hold back the highlights, allowing for richer blacks and good separation in the mid-tones.
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