a burning questiongreenspun.com : LUSENET : Large format photography : One Thread
I've been noticing a peculiar thing that I wonder if anyone else has experienced. Evident when printing 16x20 or larger, it seems that areas of my prints that receive burns are experiencing a slight loss of sharpness, particularly on the "edge" of the burn area. I was wondering if light might be refracting somewhat around the cardboard or something like that and hitting this area a bit out of registration. I don't think it has to do with the negative popping or shifting over the course of the exposure, as the problem still happens even when I change the order/sequence of my burns. I have noticed that extremely slow and delicate passes with my burning helps the situation somewhat. If any of you folks know what's going on, I'd be interested in hearing your ideas. Thanks! Chris Jordan (Boston) www.jordanphoto.com
-- Chris J Jordan (Boston) (firstname.lastname@example.org), March 13, 2002
The only thing that comes to mind is that your tools have a rough edge or are thick so the light passing the tool is reflected / difracted. Mhmm, never noticed it, mostly I cut some wasted printing paper into the desired shape with a pair of scissors and never had problems like the one you describe.
The other "not so obvious" explanation could be gravitational force excerting on the light by the tool, but to see the effect your dodging tool should be as heavy as a small planet, and that seems not to be so here :-) :-) :-)
-- Huib Smeets (email@example.com), March 13, 2002.
chris, i'd suggest making a new set of tools out of very thin black plastic or an old piece of photographic paper. my personal preference when printing ciba was to cut an old piece of ciba paper into my d/b tools. the edges of thick cardboard can cause just the kind of diffusion you're talking about, especially if there's any kind of fraying. during the portion of the time that the light is passing through the frayed edges, or passing past the thick edges, the image projected on the paper will be fuzzed both in terms of sharpness and contrast.
the other chris jordan (Seattle)
-- chris jordan (firstname.lastname@example.org), March 13, 2002.
Thanks, Chris That makes good sense. I've been using poster board that is several plies thicker than paper. My tools are pretty new, which leads me to think its the thickness in this case causing the problem. The thick edge sort of forms a "lens" which bends the light around. The devil!
(P.S. I'm still getting a kick about the name thing!)
-- Chris Jordan (email@example.com), March 13, 2002.
Chris, could this be a case of enlarger movement (ever so slight). Perhaps that is why when you are more gentle that the blurring does not happen. I am much more careful about how quickly I move my burning tools around on a bigger print. My enlarger is attached to the wall, but if I move around too much or too heavily it will vibrate. I even turn the CD player down for larger prints, because I can feel the vibration of the bass on the surface where I place the easil (spelling?).
-- Paul Mongillo (firstname.lastname@example.org), March 13, 2002.
thin or thick dodging or burning tools doesn't matter. A lot of people use their hands to make burns. Enlarger vibrations, longer exposure times, and out of focus negs. Focus is critical at 16x20. That is when any out of focus problems show up.
-- bigmac (email@example.com), March 13, 2002.
I don't think my post will be of direct benefit regarding your particular problem but may be of general interest in the dodging tool debate:
I have successfully used the black aluminium foil from Rosce that you make custom snoots and barndoors from. Long forget the name - the box went west years ago - but the material is pliant yet stiff enough to hold shape with very fine shapes while being absolutely matte black.
Just a tip.
P.S.: Another tip ... don't take sleeping pills and laxatives on the same night.
-- Walter Glover (firstname.lastname@example.org), March 13, 2002.
That'd be Rosco Cinefoil or blackwrap.....handy stuff to have around. Could be flare, maybe vibration too....I've had similar problems in our lab when making big prints with long exposures...say the freight elevator closes (way down on the other end of the building) and a slight tremble comes across the whole level I'm on, or someone enters the lab & slams the door....drives me nuts....
-- DK Thompson (email@example.com), March 13, 2002.
Just to shed some light on the post (nyuk, nyuk) that suggested gravitational influences - light is unaffected by gravity.
-- Matt O. (firstname.lastname@example.org), March 13, 2002.
Einstein's Theory of Relativity predicts that light will 'bend' around a strong gravitational source such as a star.
This was proven to be correct quite a while back, when during a solar eclipse when light from a distant star was shown to be 'bending' around the sun....the amount of bending was very, very small, but it was there.
We now return you to your regular programming...
-- Ken Miller (email@example.com), March 13, 2002.
"Light is unaffected by gravity". Really? Ever hear of a "Black Hole"?
-- Wayne DeWitt (firstname.lastname@example.org), March 13, 2002.
sounds like it might be the enlarger head slowly creeping down. try pulling on the enlarger head after locking it down to see if its tight.
-- mark lindsey (email@example.com), March 13, 2002.
Gentlemen . . . Really,
Get a grip here.
Gravity ALWAYS wins!
However, film is sensitive to thought.
-- Steve Feldman (firstname.lastname@example.org), March 13, 2002.
Man, that old light/gravity thing will get you if you're not careful. I always store my film holders standing up in "portrait" orientation. Sometimes light settles to the bottom of the holder and fogs the film. So, always remember to open the flaps all the way and shake out the holder prior to loading, and everything's OK (or wash it out with heavy water). The lower folds of your bellows are real problem spots, too.
Now, anyone seen the specs on those new gravitational lenses from Rodenstock?
-- Kevin Bourque (email@example.com), March 14, 2002.
Shoot, I forgot....you can use dark matter to soak up the extra light, too (or just take it to a good quantum mechanic).
-- K (firstname.lastname@example.org), March 14, 2002.
Guys and Dolls,
O boy! am I sorry that I made that remark about gravitational pull. Seems to be that not light alone is affected by gravitational forces......
Chris: the horse that I would place my bet on is: thin but opaque D&B tools with sharp non-reflecting edges!
-- Huib Smeets (email@example.com), March 14, 2002.
Yes, the thinner B&D tools did the trick.
I've already ruled out wobble, poor focus, gravity, etc. Thanks, everyone!
-- Chris Jordan (Boston) (firstname.lastname@example.org), March 14, 2002.