BW paper reversal processing

[csabii]

Hello!

 

I'd like to use BW paper in moderate or a bit larger size homemade

pinhole cameras. It is cheaper then sheet film, available in larger

sizes, and exposition time is -more or less- not a factor. (I'll use

tripod, and have time too :))

The "orthochromatic" sensitivity is also a plus to me.

 

Becouse I'd like to get positives, I've searched through the net to

find a detailed reversal process for papers, but the most I've found

is that: "Look for reversal process of films, start from there and

experiment"

 

It thats is all can found, then I'll start from the ilford reversal

BW film process and try to adapt it to papers, but I hope that here

are some people who hav tried this before.

 

Thank you any advice and oppinions you may have!

 

Csaba

[art_haykin]

You might try exposing and processing the paper for a negative image, then contact print it onto another sheet of paper for apositive image. I've not heard of anyone have much luck reverse processing B&W paper, but I could be wrong.

[ed b.]

It really makes a lot more sense to obtain paper negatives--that way you can print as many positives from them as you want. If you reverse process, you get a single image.

[agustin barrutia]

But use light/thin papers so when contact printing, times will be reduced.

 

Cheers

 

Agustin

[dr5 examples]

Like others have mentioned, the use of paper negs is little easier done. If you do make some paper negs, I'd recomend waxing them. This makes the paper a little less opaque and helps make the resulting print look sharper. It won't work with RC prints though, I'd suggest a rather matte FB paper. An excellent resource for paper neg making from scratch is a book called primitive photography. The information in that book will really let you get by on the cheap! Homemade cameras, neg holders, lenses, and emulsions. Who needs premade materials? Bah!:-)

 

Isaac

[j.w.]

Csaba;

 

I have been involved with paper negatives for some years now, mostly in pinhole cameras, but also in a 4x5 Speed Graphic, using both the original Kodak Ektar lens, as well as homemade plastic fresnel lens.

 

I have always contact printed my paper negatives; I haven't tried any reversal processing. However, I do know that the reversal process used in, for example, 8mm B/W movie film involves partially developing the film, then a stop bath, then flash exposing to light, then a bleach (to remove some light-exposed emulsion), then a second development, followed by the standard fix, rinse, etc. Also, what makes some films better for reversal than others is the spectrum of grain sizes manufactured into the emulsion. It seems you need an emulsion with a wide range of grain sizes to get a good tonal range when reversed.

 

How all this pertains to B/W paper, I'm not yet certain of. I suspect that multigrade paper, with its high and low contrast emulsions, may give somewhat of an adequate tonal range...but then again, I'm just speculating at this point.

 

Pertaining to contact printing paper negatives,I have used mostly MG paper for my negatives, mainly out of convenience. However, you may find that graded papers may give you a better control over contrast, which is the biggest problem I've found with paper negatives (at least for scenics). Scenic images will be especially sensitive to UV from the sun; this will activate the orthochromatic (blue sensitive) emulsion more than a light meter may suggest. I've tried MG printing filters in front of the pinhole, but this not only diminishes the effective ISO, but reduces contrast, due to the extreme DOF inherent in pinhole.

 

I remember doing an internet search a few years ago on reversal processing...perhaps I found it in the "flicker" website (dedicated to 8mm, small gauge film)...www.flicker.org; they have many links to other 8mm film sites, where you may find hand reversal processing info.

 

Let us know what you find. I think the idea of a one-of-a-kind positive image, direct from the camera, is cool. Kind of like Polaroid without the convenience of immediacy.

 

One other thing I find convenient is to shoot my paper negatives onto video. My camcorder will reverse the tones, making a positive image that can be recorded to tape (for a "slide show"); you can also scan them using a flatbed scanner, but you may have problems with glossy negatives. The tradeoff is that if you use semi-matte negatives, they scan better, but the contact prints won't be as sharp. Glossy finish gives the sharpest transfer of image.

 

I haven't tried the idea of "waxing the negative". I'd like to hear more about it, what it does to the longevity of the negative, and what the wax does to the positive print when in contact with the negative. Hopefully there's more to it than "waxing the dolphin"...

 

Cheers

Joe

[dr5 examples]

I haven't tried the idea of "waxing the negative". I'd like to hear more about it, what it does to the longevity of the negative, and what the wax does to the positive print when in contact with the negative. Hopefully there's more to it than "waxing the dolphin"...

 

 

Cheers Joe

 

The technique I've seen for waxing paper negs is to use beeswax with an iron on a realitivly low setting. As you work the wax into the paper, it looks more and more like... you guessed it, wax paper! It effectivly allows more light to pass through and sharpens the resultant positive print. After drying, the waxed neg should not have any problems sticking, and I'd imagine that beeswax is more stable than the silver in the paper...

 

Isaac

[rush]

My photo instructor once gave me some special photo transparency paper. It supposibly develops like regular paper, but it transparent. You could allways use that for the negatives and then print positives off that. I forget the name, but I will post it when I remember.

[laurent_cochet]

If you really want a direct positive image on a regular bromide paper, it is possible by using a normal paper developper for the first step. Then bleaching it in a potassium dichromate 10gm/Sulfuric acid conc.12ml 1liter sol.Next in a 5% Sodium sulfite. Rince between each bath. Next reexpose the paper and reprocess developper/stop/fix/wash like a normal B&W paper. The trick part is to reexpose the paper with the right amount of light. The best thing is to use an enlarger with a timer. Have fun.

[diego_trujillo]

Instead of using BW FB or RC papper use Kodalith Orthochromatic film, it is about the same ISO as multigrade papper (ISO 4-8) and is processed in the same way, the only difference is that the base is already transparent so oiling or vexing the papper is not necessary.