The Paper Negative

[JamesD]

This is a continuation of a thread that got a wee bit off topic. The previous posts can be found here: http://thephotoforum.com/forum/showthread.php?t=47730

 

[JamesD]

For reference:

There's a certain low level of light which will not expose paper. I've read it described as "chemical inertia," meaning that the photons hitting the silver just aren't enough to start the reaction. The analogy given was pushing a car: it's hard to get the car rolling when it's stopped, but once it's rolling, it doesn't take as much of a push to keep it rolling. Similarly, the few photons striking the emulsion in very low light just aren't enough to get the silver changing to begin with.

So, flashing is a technique used under an enlarger (or in a pinhole camera, I would assume) which gets the chemical reaction going, so that the light hitting the emulsion won't have to "push" as hard, allowing very faint light to keep changing the silver in the emulsion.

Basically, what you do is expose the paper to light (enlarger light, room light, lamp light, whatever) either just bright and long enough to barely fog it, or just less than enough to barely fog it. You'll have to develop it, of course, to figure out whether you're giving it enough light (or make sure you're not giving it too much). Once you've figured out the right intensity and/or duration of the flash, you flash another piece of paper and load it into the pinhole camera.

Which brings us to the reason why I asked in the first place: if you try flashing the paper, it might give the emulsion enough of a kick in the seat to record your low-light scene.

Beware, however: I've also read that flashing is temporary. If you flash a piece of paper, then put it away, the effect will disappear, and you'll have to flash it again. I think this applies to flashes which are just barely too little to fog the emulsion; once you have fogged it ever-so-slightly, I think it keeps the fog--but I'm basically guessing on this. I have no idea how long it takes the emulsion to forget that it's been flashed.

We used to do that with slide film to kill some of the contrast. I never heard of it for this purpose. i would think you would need a stronger light that the low light of the studio. Maybe aim it out the widow a the sky for a second or two then try it. Im not sure.

I think that in this case, you just want a very little bit of pre-exposure, just barely enough to get some density if you develop it. You'll have to try a few times to see how much you need. I would go with something more reliable than the sky, myself; perhaps a card-board box with a hole cut at the top and a ceiling light, perhaps... put the paper at the bottom of the box, with the hole covered, under the light. Remove the cover for the specified amount of time, then cover it back up and load it into the camera. That way, you've got some consistency in your pre-exposure.

Not a pinhole, though. That would pre-expose an image of the light fixture LOL. Or, perhaps a small hole with a sheet of white paper over it as a translucent, diffuse source. Hmmm....

 

[mysteryscribe]

or a shot of the clear blue sky or gray clouds

 

[terri]

This is a continuation of a thread that got a wee bit off topic. The previous posts can be found here: http://thephotoforum.com/forum/showthread.php?t=47730

Hey, getting off topic is what some of us do best, Mister. :mrgreen:

Thanks for pulling all this together again. Good stuff! :thumbup:

 

[mysteryscribe]

This morning I began my controlled (for me anyway) experiment with the paper negative indoors. Okay I have the paper negs washing now. I exposed one for two minutes and one for eight seconds the difference is remarkable. However at this moment I'n not sure which is which. To make the controll I developed them both in the same tank at the same time. They got mixed up lol... I'm no scientist I'm an artist.... not a word terri...Ill post both in a few minutes when they wash and dry. The difference is quite remarkable. And not at all what I expected. I have a good idea which is which based on previous paper negative results.

 

[mysteryscribe]

Okay I shot the same shot I thought at f8 @ 1/8 sec then again at f32 120seconds... these are the two shots. One neg looked good and one looked thick. Somebody with more patience than me needs to verify it. I tried to repeat it but cant get both shots to come out at the same time. I'm giving up.

On a retry I have one good paper negative it was shot at f32 for 120 seconds. leading me to believe the better negative was f32 at 120 seconds.

It was a tricky lighting situation only in that all over the potato the readings were different. I exposed for a spot just barely in the shadow then used it to calculate both shots.

The one thing I have done differnt from yesterday when I had such miserable luck with the paper negs is that I am using a different developer mix. That could account for the better long exposures I suppose. I think the 8sec is just over exposed and the two minute is better because of the light failure at that length of time. That is just a guess.

My gut feeling is to go for the shorter exposure time in spite of these results. i will be shooting more paper for a while and trying to get a better feel for it.

James you should try to figure out whether better negs are made with times as short as possible or times as long as you can manage. I can tell you that on film if there is a difference it is slight but on paper it is real. At least I think that is the case.

 

[JamesD]

By thick, you mean dark? And I'm assuming that you were using lens and paper? What brand of paper are you using, anyway? I'm making a list of experiments to do this weekend... I may throw that one 150mm lens and shutter I have into a box this weekend, too, with a waxed-paper focusing screen. I'm certainly going to do SOMETHING this weekend...

Oh yeah, the view camera project... hmmm.... I need to evaluate my priorities here before I arrive at a decision LOL. The wood shop is closed on sundays, though, so I'll get at least SOMETHING done that day.

I'll get back to you on that.

 

[mysteryscribe]

Im gonna keep shooting some paper this week. Im suing a #3 rc at the moment and it does pretty good. Im thinking the exposure is different as the time drags on more than the retroprocity thing even. I am proably worng I know nothing about what we are doing just playing. The outdoor ones are perfect almost everytime. Its the inside that is making me crazy.

thick is an over exposed negative... thin is an underexposed one named for obvious reasons.

 

[JamesD]

I'll be using some old (outdated, I believe, but it was free) Ilford VC paper, and I'll probably try using the VC filters, just to see.

My range of lighting levels is gonna be a bit limited, probably, but I'll make what notes I can. Perhaps I can turn a box into a mini-studio, with a variable-size opening for light. We shall see.

 

[mysteryscribe]

For still life I use a trouble light from home depot and a sixty watt bulb... Very slow shutter speeds...

 

[JamesD]

I saw that when you posted about the trouble-lights before, and thought it was a great idea... so I went and got two of them, two sizes. Right now, I've got a 100 watt in one and a 40 watt in the other, they'll handle 300 and 100 watts, respectively.

On pinhole day, I needed more light, so I made a reflector out of a sheet of foam-core board and aluminum foil... I didn't think the plain white surface would be enough, so I crinkled up the foil, then carefully spread it back out and taped it to cover one side of the board. It made the difference between the sucky second exposure and the nice third exposure that I finally used.

Later that day, I was down at the store and realized... those windshield reflectors that fold out accordian style, or even the ones with the flexible hoops you can twist up into a quarter their normal size... they're generally reflective, too, and quite portable.

One of my first shots, albeit on film, was illuminated with a single, army-issue flashlight. It came out beautiful and moody.

I've used plain black or white cloth, cut straight from the bolt at WalMart, as backgrounds. I've also got a canvas painting dropcloth I plan to use for a background, or maybe a lightbox, or something...

It's easy and fun to improvise! And most of it works good!

 

[mysteryscribe]

Ah the canvas painted backdrop. I got this wild hair to have a rembrant backdrop. Of course they sold for about two hundred bucks at the time. I mean for a decent sized one. I went to the paint store and bought a 9'x12' panter's dropcloth. Even after I cut out the parts with seams I had a respectable 6x8 foot drop.

I had seen a home improvement show about painting with sponges. So a can of black, a can of white, and a can of pink paint made it onto a 2x2 sheet of 1/4" plywood used for a pallet. A real sponge, I have no idea why I bothered, and off I went. The canvas was streched and nailed to a wooden frame first of course.

When I finished, I had a backdrop that changed with the lighting. No back light and it was dark and moody. With a backlight a million color variations. Add to that the wonderful fact that most of the labs in town recognized the background and refused to copy prints made on it without calling me first, and you have a double sawbuck wonder. I still have it rolled up in the abandoned studio. I made a half dozen more over the years but none like that one.

Yes colored cloth makes a good background it is usually non reflective. I always always planned to run black indoor outdoor carpet over the floor and up one wall to make a seemless black bridal backdrop, but alas I never got around to it. The benes of it are obvious it wouldn't wrinkle, you could use a vacumm with wand to clean it of dust, and it would absorb the light with absolutely no reflections at all.

The only thing about a black background is the bride better be blonde, or have a head piece or she has no hair in the pictures.

Reflectors: take a look at the office depot for those science fair boards. They are cardboard and have two wings. They make and excellent table top background and you can use them for reflectors as well. That is if you cover them with something...

One more note on reflectors: let me say just this. Alum roof flashing, you can cut it with household scissor, attach it with spray adhesive and it is a very hot reflector. If it is too hot just drape a white cloth over it. It is reasonably inexpensive and a heck of a lot more durable than foil. I usually have a half roll laying around for camera projects.

 

[mysteryscribe]

okay I think I have figured out how to shoot the paper neg indoors. Put a light on the subject at least enough to raise the light quality some. I hit a still life with just a 60 watt bulb in a reflector from about three feet. The exposure read 30 min I added 50% kentucky windage and the paper neg was perfect. Well perfect enough for me. It's drying now. I'll post it when it is dry enough.

The film negative looked better of course but the exposure at two mintues was just fine. now on to backlighted objects exposed for the shadow. Lets see how that does with a small amount of front light.

 

[mysteryscribe]

This is a 45 minute paper negative print. Light was one single 60 watt blub in a trouble light.

 

[JamesD]

Forty-five minutes?!