Paper Negs

RJS said:

Dann - your posts are just in time! I plan to try the paper neg in an old Sanderson full plate camera using book-type holders. Yours look terrific - but how did you print/reverse them?

Click to expand...

Scan them into the pc, and flip them to negative in a graphics program like Photoshop, Paint Shop Pro, Gimp or whatever's available. I haven't learned to do a "good" contact print yet. So that's why I'm hanging around you all. Maybe something will rub off.

Photo Engineer said:

Azo is way to slow for camera exposures. It is mostly UV sensitive. Try using MGIV or graded Ilford papers metered at ISO 25.

PE

Click to expand...

PE
I have some Kodabromide SW3 ( aged back to about grade 2 now) in 5x7.
Could you hazard a guess for starting EI, exposing in camera?
This paper does not seem to have any significant base fog but may even be grade 1 now. But it is thin which seems desirable for a paper neg.
Mark

RJS said:

Dann - your posts are just in time! I plan to try the paper neg in an old Sanderson full plate camera using book-type holders. Yours look terrific - but how did you print/reverse them?

Click to expand...

If you haven't tried it yet, then I do believe you'll enjoy this. There's something about it that's "slow good". The "big evil" is wind. When I do outside exposures I need to tie her down good, or have a very sturdy tripod. I had to make a heavy duty tripod from wood to be steady (semi-vibration free) on mildly breezy days. 8 seconds is a long time.

Some comments;

1. The contrast of MG paper and its variation with illuminant can fool you as to speed. I've used ISO 25 and gotten the results posted, but the toe is sharp. I would use a graded paper with grade 1 or zero instead of a MG paper if I were to do serious work making paper negatives. It is ok at higher contrasts if you want to reverse it directly in PS.

2. Kodabromide was (IIRC) several stops slower than current papers. I have not tested it for years, but I would suggest starting at 6 or so. Again, the contrast will probably be too high for general work, but can give good results.

3. Endura shot in-camera with color filters to balance for daylight will yield about ISO 6 - 25, depending on lighting. See posts by Bujor B on www.photo.net. You may also wish to cross process to get transparencies on paper or the translucent support. This does not appear to work well with Fuji papers.

4. Contrast and speed reciprocity failure affect all enlarging papers if exposures get too short or too long. You will have to test and be the judge for each paper.

PE

More information on speed points of paper materials.

Graded papers vary in contrast. This can be achieved in one of two ways. One is to maintain the same threshold (toe) speed, and just make papers with lower or higher contrast. This would have the effect that the papers would appear to have quite different effective on-easel or in-camera speeds, as the mid tones, to be proper density, would require higher exposure.

The curious thing about this is that by the strict definition of speed, these papers would have the same ISO speed. The EI (Exposure Index) or actual speed you would use would decrease with contrast.

The other method is to pivot the curve around a central density unit by chopping back the toe and raising the shoulder. This type of contrast control gives the appearance that all grades of a graded paper type have the same speed on-easel or in-camera. To achieve a given mid scale density, you would use the same exposure for each paper which was graded by this method.

The curious thing about this method is that these papers would each have a different ISO speed. The ISO speed would decrease as contrast went up, but the EI would appear to be the same.

To test the speeds of these papers, designed by either method, one would need to use something similar to the zone system whereby the selected image is centered on the center of the tone scale of the paper.

Since papers are made to varying contrasts or graded contrasts, and films are basically made to the same contrast, the exact comparison of a film and a paper product are usually very difficult. The most accepted way is to expose a paper to center the image in the middle of the tone scale as I did in the posted examples (see the other thread). The paper is then developed to the maximum threshold speed consistant with the desired gamma of the paper. (This basically means don't overdevelop your paper)

However, if you are using various grades of paper, you should run tests to see which method is used for controlling contrast. This will help you understand what is going on with any given manufacturers papers.

Multigrade papers, exposed in-camera to colored objects will, as I said before, vary in contrast and apparent speed in a given scene based on the color of the object. The contrast and speed observed would be based on which of the two methods were used to design the paper.

I have used both methods in the design of paper products. They both work equally well, they are just different.

PE

Forget the AZO, or were you trolling. Keep it for what it does best, or sell it to me. (there was a url link here which no longer exists) a bunch of paper negs I did. I also did paper neg prints for the post card exchange here this time.

I really like the chair, very good. Thanks, Pat

My light reading today was EV 11.4 for an exposure of 2.5 minutes @ f/64, # 2 was the same but for 3 minutes. Will print tomorrow. Pat

clay said:

Well, i know this is heresy for some, but I use Ansco 130 ink. Good enough for Ansel, good enough for me.

Click to expand...

Hang on - so... Ansel had an inkjet?!

p krentz said:

My light reading today was EV 11.4 for an exposure of 2.5 minutes @ f/64, # 2 was the same but for 3 minutes. Will print tomorrow. Pat

Click to expand...

Going back to some of my previous posts, I keep wondering if you and others are not running into a speed reciprocity failure problem. Most papers were not designed for that exposure time. I have a funny feeling that the EV could be higher if the exposure time was shorter.

PE

Photo Engineer said:

Going back to some of my previous posts, I keep wondering if you and others are not running into a speed reciprocity failure problem. Most papers were not designed for that exposure time. I have a funny feeling that the EV could be higher if the exposure time was shorter.

PE

Click to expand...

Speed reciprocity failure problem? Heck that's just humans trying to impose limitations on mother nature thru the use of numbers on a chalkboard. Nature could care less about chalk and formulas. If the math doesn't come out, too bad, too sad. If it works, then it works . . . . doesn't matter how you got there.

How's that for little "light reading". ;-) Dry humor.

DannL said:

Speed reciprocity failure problem? Heck that's just humans trying to impose limitations on mother nature thru the use of numbers on a chalkboard. Nature could care less about chalk and formulas. If the math doesn't come out, too bad, too sad. If it works, then it works . . . . doesn't matter how you got there.

How's that for little "light reading". ;-) Dry humor.

Click to expand...

However, if you cut the exposure time to about 1 second instead of 2.5 minutes, you might find that your EI had risen by 2x. IDK. Just a suggestion. My exposures with Ilford MGIV range in the 1/8th - 1/125th second range metered at ISO 25. Certainly this is a lot different than yours, and may give a different ISO value for the best exposure.

PE

Photo Engineer said:

However, if you cut the exposure time to about 1 second instead of 2.5 minutes, you might find that your EI had risen by 2x. IDK. Just a suggestion. My exposures with Ilford MGIV range in the 1/8th - 1/125th second range metered at ISO 25. Certainly this is a lot different than yours, and may give a different ISO value for the best exposure.

PE

Click to expand...

PE -

if exposure times in-camera are very short ( asa 25 ) thank enlarging times should be very short too ... how come when i set my light meter in the darkroom at asa 25 ( measuring light from the projected image from the enlarger ) ... i get a blank piece of white paper after i soup it, and when i do test strips, i am more in line with my paper's asa below 10 ?

just wonderin'
-john

jnanian said:

PE -

if exposure times in-camera are very short ( asa 25 ) thank enlarging times should be very short too ... how come when i set my light meter in the darkroom at asa 25 ( measuring light from the projected image from the enlarger ) ... i get a blank piece of white paper after i soup it, and when i do test strips, i am more in line with my paper's asa below 10 ?

just wonderin'
-john

Click to expand...

I would just guess that the light is too dim from an enlarger to register accurately on a meter. I see what you do in terms of making paper strips, but I cannot really verify the ISO of an on-easel exposure of paper. I can only make actual measurements in-camera. There, I use the camera meter (RZ67) and a hand held Sekonic meter.

My exposure on-easel is about 12" at f16 - f22 for an 8x10 from a 4x5 negative. This is using the same papers that I exposed in-camera at ISO 25 to yield the picture of the MacBeth checker I posted. The in-camera exposure for both papers (mine and the Ilford paper) were 1/50" at f8, so reciprocity may figure into this. The very short exposure and relatively high intensity light changes the response of paper emulsions.

Another emulsion, not posted, was 1 stop slower and was properly exposed at 1/50" at f5.6. On-easel, it also required an additional one-stop increase in exposure. So, the results are rather consistant. They give me a general calibration of both my emulsions, and my enlarger.

PE

Photo Engineer said:

I would just guess that the light is too dim from an enlarger to register accurately on a meter. I see what you do in terms of making paper strips, but I cannot really verify the ISO of an on-easel exposure of paper. I can only make actual measurements in-camera. There, I use the camera meter (RZ67) and a hand held Sekonic meter.

My exposure on-easel is about 12" at f16 - f22 for an 8x10 from a 4x5 negative. This is using the same papers that I exposed in-camera at ISO 25 to yield the picture of the MacBeth checker I posted. The in-camera exposure for both papers (mine and the Ilford paper) were 1/50" at f8, so reciprocity may figure into this. The very short exposure and relatively high intensity light changes the response of paper emulsions.

Another emulsion, not posted, was 1 stop slower and was properly exposed at 1/50" at f5.6. On-easel, it also required an additional one-stop increase in exposure. So, the results are rather consistant. They give me a general calibration of both my emulsions, and my enlarger.

PE

Click to expand...

PE

thanks for your explanation ...
while i've been exposing paper in-camera for i dunno, 15-20 years? and i have to admit i am skeptical that paper has an asa that high, i'll stick some paper in my camera make some exposures at asa 25, and then the same thing using asa 6 ...

thanks again for your methodology ...

-john

John;

I remember an argument during a design meeting at EK.

Two of us were testing the same paper with a new emulsion, but getting different curve shape and speed. We looked at latent image keeping and light temperature and lots of things then realized that one of us was using 1/2" and the other was using 10" with an Iconel ND filter in the beam. Both were standard exposures, but one was for photofinishing materials (Mark III and IV printers) and the other was for enlarging papers.

The difference with the new emulsion was different contrast and speed reciprocity which didn't match the old product which contained Cadmium, and that was my first introduction into reciprocity failure tests. We had to completely reoptimize reciprocity failure and then develop a feel for the response of this new emulsion.

I went and checked an old folder here at home and found a blank sheet of EK reciprocity test graph paper that we used back then for checking the toe, mid scale, and shoulder for speed and contrast changes just for the reasons I described in my other post.

That one fact tied us in knots and delayed the project for about a month IIRC. We just didn't expect such a big difference. Theory and raw emulsion tests didn't predict the actual final results when the emulsion was coated with all features in place.

PE

Are folks using hardening fixer on your paper negs, as you would for your film negs?

PhotoPete said:

Are folks using hardening fixer on your paper negs, as you would for your film negs?

Click to expand...

I can only speak for myself, but I follow the stop bath with Ilford Rapid Fixer. And a good rinse. If it has hardening properties? I'm not sure.

hi pete

i've never hardened film or paper ...
i think some companies ( ilford?) suggests
hardener does more damage than good.

-john

I've been using VC RC papers,putting a 0 or 00 printing filter in front of the lens/pinhole on bright days and developing with old HC110 by inspection or NeutolWA and getting very good results.
Theres some images in my gallery of these efforts-feel free to PM with any questions you might have. Have fun!

I never use hardener on film or paper, just pure hypo. Pat