I need your help

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David A. Goldfarb said:
Thanks. Not a criticism, but just curious.
Click to expand...


No, good point.

The effect is not in the negative, but I did find one thing. See my definition of 'expert' above? Well, I took another look at the negative and had forgotten one little thing in addition to the previous posted reasons.

I exposed through the base, which would increase apparent flare a bit, wouldn't you think? So, I have just flipped the image and reprinted so I now will get the same print emulsion to emulsion not emulsion to base.

DUH.

Where was my brain. Have to go see the wizard of OZ.

I do still have to contend with the image scatter induced by paper fibres. In fact, if you look at the paper negative pic, you can see the fibres have clearly influenced that image.

PE
 

sanking

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PE,

What is the surface appearance of your AZO like paper? Glossy, luster matte?

And have you experimented with Pt./Pd. emulsions?

Strikes me that if you are getting luster surfaces with AZO it should be possible to do the same with Pt./Pd. which might be interesting to some people who are interested in something other than the matte surface look we usually get with Pt./Pd.

Sandy
 
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Sandy, I get the surface of the paper I coat on. If Vellum, I get vellum, if Watercolor, I get watercolor and if high gloss, I get high Gloss. The ones posted so far are a mix of Bergger COT320 and Strathmore Smooth.

I have coated the Azo type emulsion on glossy baryta FB and have gotten a glossy finish.

I have not done any work with pt/pd. I hope to get the opportunity but it is not my forte.

PE
 
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David A. Goldfarb said:
Thanks. Not a criticism, but just curious.
Click to expand...

David, I have been examining these prints myself, but more for coating defects and for contrast and speed, so outside objective comments are very welcome. I am also very aware of the potential for flare from paper fibres.

I went back and reexamined a number of prints for flare and tried to reevaluate the images. All of them show a 'scatter' or loss of sharpness at the edges which is related to the paper fibres as I expected. You can clearly see that using a loupe.

The picture that you refer to is the only one with severe flare in the dmax region and it was printed through the base of the negative. Sorry about that, I thought I had caught everything.

So, here in two other pictures is a rather black hat against a white sky and some snow and trees to take another look at. It is printed properly. The grade 2 print is from a 5x7 digital negative and the grade 3 print is from an 8x10 digital negative, both printed emulsion to emulsion. They were scanned at slightly different resolutions to give approximately the same size images. One is on COT320 and the other is on Strathmore smooth.

When you have limited chemistry, you combine experiments, so I'm sorry for the differences. I have left in the tonal differences. The Bergger is slightly more brown than the Strathmore. I hope that this shows up in the images.

PE
 

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David A. Goldfarb

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Thanks. Those are interesting as points of comparison.

Have you had a chance to compare traditional negs to the inkjet negs? I'm wondering if that might not also be a source of scatter.
 
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David A. Goldfarb said:
Thanks. Those are interesting as points of comparison.

Have you had a chance to compare traditional negs to the inkjet negs? I'm wondering if that might not also be a source of scatter.
Click to expand...


Yes, I have compared inkjet and traditional. I see differences. I'm still working on that. Too much to do, too little time.

PE
 
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To answer questions from those who have asked me. Here is the thread with the formula for the basic AgCl emulsion used in the contact prints above.

(there was a url link here which no longer exists)

I have had to modifiy it from what is posted based on the Bloom Index (BI) of the gelatin used, and the source and quality of the gelatin and also have had to adjust addition times a bit and well... Take a look at the formula and my suggestions. The bottom line is that it works and here are examples.

Remember too, these pictures were not supposed to be prize winners, they are R&D evaluation samples to check out coating uniformity, speed, contrast, etc..... Not to go out there and impress you with my photographic acumen. These are taken from old family snapshots for quick and dirty tests.

Thanks for all of the e-mail queries. I welcome your comments. I will try to answer all messages.

PE
 

smieglitz

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Photo Engineer said:
To answer questions from those who have asked me. Here is the thread with the formula for the basic AgCl emulsion used in the contact prints above.

(there was a url link here which no longer exists)

...
Click to expand...

If I read that correctly, there's no noodling or ripening steps involved?

Sounds much simpler than the recipe I tried years ago. That one involved straining the emulsion through cheesecloth and lots of washing of the noodles. This was repeated several times over a period of days before the emulsion was usable. IIRC, potassium bromide was in that emulsion. Does the bromide complicate things or is something else going on?

Joe
 
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Joe, I'm trying to keep this simple. So, for contact and slow enlarging speed there is no washing or 'ripening' as you may be familiar with. This creates other problems but simplfies the process a lot.

Coating on film support or RC will require washing, and camera speeds will require 'ripening'.

I would also like to distingish a bit here between ripening and finishing. These are two separate steps. Ripening can be divided into plain ripening (Ostwald) in which large grains grow at the expense of small grains. A large quantity of solvent does not need to be present. Then there is digestion, another form of ripening in which a large quantity of a solvent is present. These two forms often overlap and are hazy in distinction.

Then there is finishing which also 'ripens' grains while adding sulfur and sometimes gold to the emulsion.

All of these increase speed, fog and contrast and must be carefully controlled or the emulsion is ruined. I'm trying to minimize the effects of all of this and this speeds up the overall repeatability and makes things simpler.

But, if you look at the formula I posted before, there is a 5 min hold after the pptn of the silver, and this, in the presence of the excess halide ripens the emulsion. When I post the other formulas you will see similar ripening steps.

Adjusting curve shape does require doping and doctoring with salts. There is ripeining of a sort going on here as well. That will also be explained when I get to posting that part.

As for washing, I am trying to get a PA washing sequence worked out using a good quality Phthalated Gelatin. If it goes well, that will simplify washing a great deal. If not, back to noodling. In fact, I have an emulsion that needs noodle washing right now.

PE
 

Jim Chinn

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Looks like in light of the recent news about AZO those 10 years went by pretty fast for contact printing papers.
 
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An update for you all.

I have run tests on the imaging flare question brought up by David Goldfarb.

In answer, the picture of the people with the automobile is the only one with the 'flare' and the 'flare' vanishes when printed on baryta paper. Whether the print is made base to base or emulsion to emulsion has no effect. I am limited in my supply of baryta paper, so this is a 'provisional' result subject to change as experiment size increases.

I have to assume it has a relationship to maximum density in the sky vs step chart, and also flare induced by being coated directly on paper fibers. It is not infectious development as far as I can determine.

In terms of repeating the ISO 100 film, I goofed in my repeat and used NaBr equal weight instead of KBr, but in spite of this the paper negative was about ISO 75, and the actual film negative was about ISO 25. (you see, we all make misteaks)

I am still working hard to produce user friendly emulsions for contact, enlarging and film speed materials.

The contact speed emulsions are essentially done and in fine shape. The enlarger speed emulsions have the speed but not quite the contrast control I want, and I am still working hard on the camera speed emulsions. I have 9 spectral sensitizing dyes for the camera speed emulsions to try out, and I have also gotten an AH dye for sharpness. So, work progresses.

PE
 

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Good to hear.

I shudder to think what materials made this way would cost, but it sounds as if the kits to make them at home won't be prohibitive, especially as silver photography retreats into a "boutique" niche and prices rise as economies of scale are lost.
 

David A. Goldfarb

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Thanks for the update!
 

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PhotoEngineer, thanks for posting. I can see that that there is potencial hidden in that emulsion. Your posted print is from a scan of a print 85 years old, which has been turned into digital negative and reprinted in your silver chloride coated paper. I still would love to see a print from an 8x10 negative. Hopefully somebody will post. If not I would be willing to supply one one of my negatives for such treat.

PhotoEnineer, If you are going to give a workshop somewhere in the west coast I'd be interested in participating. I live too far... all the way in Hawaii, so closer is better.
 

Claire Senft

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I would guess that my opinion would be formed by three factors:
1). The intrinsic differences in cost, shelf life and performance between the ready made emulsion and preparing them myself.

2). The continued availabilty of fiber based paper at an affordable price

3). The investment in equipment and education to do this work.


Just as a thought. For the worker who works in car-bro this should be a wonderful way to obtain non-supercoated papers with a bromide emulsion. Perhaps, though, I have misunderstood some of the threads involved.
 
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The carbon sheets can also be coated with good quality using the coating blades, as I demonstrated for Sandy King a month ago.

However, in your list above you miss one important factor, sorry to say.

Research in analog is dying out. Researchers are ageing. Only researchers know enough to recreate or teach the entire process. So, someday if analog dies out to a great enough extent, there will be no one to teach the technology to those who do want to learn. Now is the optimum time to pass on that information, otherwise the chance that it will be lost increases every year.

Please factor that into your thinking as well.

PE
 
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I have no 8x10 negatives made in-camera, as the largest camera I have is 4x5. I understand your feelings, but I have to rely on an expert at contact printing myself. Mike Whiting is such an expert IMHO, and so when he says it looks good, it must look good! I would wait until he has a satisfactory print and a method to scan it, before I would judge any further.

My next workshop is in NY in Sept.

PE
 

Claire Senft

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Thank you Ron for your response. I am already retired. From a purely selfish standpoint I am thinking in terms of the next ten years.

I have great respect for the work that you have done. I hope that this is a very rewarding project for you in both satisfaction and in paying you for your time and effort. How nice it is to have a person of your capabilities on APUG. Appreciated is your helpfulness.
 
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Thanks for the comment.

The funny thing is that sometimes this is just like being back at work.

In any event, I'm planning for a possible future more than 10 years off. I'm not sure of the real timing as much as some here on apug are. Some here are so positive about the unknowable future, that "Undiscovered Country". I'm just trying to help pave a possible path for whenever it takes place.

At the same time, hand made photographs in B&W are becoming quite fashionable, command some good prices, and so the time to teach some of this appears to be now.

PE
 
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