View Full Version : New Silver Chloride Azo type paper

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Alex Hawley
01-12-2008, 03:34 PM
unremarkable in many ways - perhaps - , but in the hands of a photographic artist - beauty is most surely achievable.

As I write this, I am looking at Alex Hawley's Beautiful 8x10 contact print - "Barn Siding" - printed on Strathmore art paper coated by Ron Mowrey with his silver chloride contact printing formulation. This is a beautiful print and it is IMHO, very similar to AZO. Alex developed this print in Ansco-130 and Selenium toned it.

"Barn Siding" shows the "3 dimensional" light and shadow effects that I associate with AZO prints and PtPd prints made by master photographers/printers.

Many thanks for those very kind words Tom.

One of my goals in selling that portfolio was to get it in front of someone knowledgeable and objective with a critical eye. I think Tom possesses those traits so I hold his opinion in high regard.

01-14-2008, 02:23 PM
It is possible to estimate the resolution, when you compare it with a standard bw-paper?

Photo Engineer
01-14-2008, 02:58 PM
Yes, with a simple set of resolution charts. I have a 4x5 negative and positive chart that I use. I have posted some examples here on APUG. Support is more important than any other factor.


01-14-2008, 05:49 PM
To measure resolution has been my passion, and sometimes it ruined my eyes. But any better paper is of interest and I will try a MTF-function for this paper and -taking the opportunity- to similar paper types. The quantity is very little for that, because I will work in 24x36mm, using the paper as film in the RTS III thanks its vacuum back.

Photo Engineer
01-14-2008, 06:42 PM
MTF of paper is almost impossible to measure and rather meaningless unless it is measured in a viewing cabinet with instruments. The angle of illuminant, viewing distance and many other factors make up part of the problems that do not exist when measuring film.

I can only say that very heavily packed baryta with a glossy finish gives the best sharpness, while low levels or no baryta on soft cold press papers give the worst sharpness visually.

However, at the same time, contrast can be confused for sharpness and this confounds the issue.


01-14-2008, 09:29 PM
When no MTF exist, perhaps is that the reason, that - lets say- esoteric values will appear to determine paper qualities. This is here in apug just running with "3-dimensional look" in paper. I am impressed about the lyric textes and the descriptions about the feelings. I prefer, what I can measure. And to measure is a lot of work.

In past, the same unhappy situation was with optics, some people were writing lyrik articles about this and that to an optic. Today thanks some japanese (is it correct?) we got a discussion about Boukeh, together with the point diagram. Today we can measure an optic. The same I want for paper.

Photo Engineer
01-14-2008, 10:04 PM
Well, angle of view is important with a print. We found that Goniophotometry showed this to be true, but never formalized it beyond showing it to be important.

For those interested, this is roughly the relationship between viewing angle and surface reflectance.


01-15-2008, 12:19 PM
There is written a lot about surfaces and measuring, starting from like - The Gloss Characteristics of Photographic papers by L.A. Jones and M. F. Fillius, no.134 in Abridged Scientific Public. Eastman Kodak, Vol. VI,1922 - to the extrem carefully with all possible goniophotometer-possibilities - Photometrische Untersuchungen an photographischen Papieren verschiedener Oberfläche von Wolfgang Falta, Jenaer Jahrbuch 1954/1, page 92-191. In my eyes the bible for paper-surfaces, a must for the Getty-collectingpeople today.

Never I read about incorporating optical thinking in emulsion-making. Once a cine-man told me about his problems with reflexion from the surface of the film-emulsion. In optical terms you minimize reflexion with interference-filters - the so called coating. What's with "coating" in emulsions? To calculate the right refraction-index for the safety-gelatine at the end of emulsion could be interesting, if - this seems possible - you can reduce reflexion even only few percent. This helps Hollywood.

To reduce reflexion on glossy paper would be the same, another way to reduce reflexion was done with Gevaluxe. It has no safety-coating, and testing this paper after 50 years storage shows no fog.

If somebody will ask me, what is the quintessence, the minimal necessary measuring for quality, I as a Dipl.-Ing.phot. (photoengineer) would answer to the normal amateur:

You know, what is a gradation curve. Please imagine -parallel to this gradation curve- a curve of highest resolution. At around density D = 0,4 -let's say- will be the point of best resolution. At higher densities the curve will going down. Depending on the different developers on the market, this function will have very different "GOING DOWNS" of the higher densities parts of this resolution curve. What make the curve going down and let show Highlights looking grey-smeared? It is the diffusion aspect of oxydised and infecting developer, of halogene, of luminescence, of infecting silver ions and so on. You measure the resolution, when you photograph testtargets in different contrast from underexeposure up to 12 stops overexposure. The humanoid negative factor by this work is - it is a lot of work.

How could this done in simple filmtesting? I found a good example, showing in the motive for the testobject a 10 stop range - please see only to the pictures

filmspeed 25-64 ISO
filmspeed 100 ISO
filmspeed 125-400 ISO
filmspeed 400-3200 ISO

This I want to see in paper-testing. The work would I do, and nobody needs to pay me. Its my own job.

Some more simpler testing is using FOGRA or UGRA- stripes from reprographic industry for screendot-projection (I dont know the US-variants), but they use high contrast. The negative you enlarge on the paper, will never have high contrast values, because its max. density is normally around D=1.8. I am thinking to check the idea, to change a FOGRA-UGRA stripe to contrast 1:30 and/or 1:1.6, perhaps this would be more in the direction of the GOLDBERG-DETAILPLATE. (E.Goldberg - Der Aufbau des Photographischen Bildes, Teil I: Helligkeitsdetails, 2. edit., 1925, my exemplar is stamped: Kodak Ges. m. b. H., 76 Markgrafenstr. Berlin) With this detailplate you can get with one test the most possible datas from an emulsion - for resolution, diffusion, gradation, point-spread-function.

Looking to whole field of science, at first you must look to the individuum itself. Every human see a little bit different, and the data-connecting of the eye-signals is different. Next is measuring from institutes, national or global, all sensual aspects in feeling, here in Germany is this done by www.grp.de since 40 years all 5 years with 4000 people. The results show a intensiv change in the feeling of viewing - anything you see gets a more importance, the ethic values from your memory will not asked more than in earlier times.

Looking to whole field of science, at last you mention to see in 3-d a quality, this is mentioned in the text "Für ein neues Photopapier" -for a new photopaper- from 4. jan. 2003. Anything, people is mentioned in forum 46113 in seeing differences in a better paper, all about the subtil mechanism of unconscious, there it is. Sorry, it is in german, but for these, who want to read the original, look to /download/neues_photopapier.pdf on


Thank You for your patience.

Photo Engineer
01-15-2008, 01:14 PM
The qualitative examples shown in your references mean absolutely nothing unless suplemented by hard data.

I will post again here, the two pertient graphs from Mike Kriss' treatment of the subject. The entire paper is 60 pages long and mostly math.

Basically, the left chart shows the traces from edges of 10, 100 and 1000 micron lines, and the right chart shows the contrasts taken from a step wedge of each of these sets of lines. You will note therefore that contrast is a function of magnification as much as sharpness is.

This means that the greater the magnification, the higher the contrast, but this is offset by the magnification itself. At equal magnification, the increased contrast increases apparent sharpness.

This crossover between sharpness and contrast will confuse you if you don't have hard data, but of course pictures are more important than data. But it still proves nothing, it only proves what we percieve, not what is. That is why you need both in a side-by-side comparison.

To get more data, it is useful to do the line exposure by visible light and X-ray both to aid in determining actual sharpness and sharpness degraded by turbidity and inter-reflections from the base. This latter experiment is critical in the design of any film system.


01-15-2008, 01:35 PM
To reduce reflexion on glossy paper would be the same, another way to reduce reflexion was done with Gevaluxe. It has no safety-coating, and testing this paper after 50 years storage shows no fog.


If you are interested in minimum reflection of the print surface, I would suggest obtaining some JDSU (formerly OCLI) HEA glass. It has a multi-coating 'high efficiency anti-reflection' coating which reflects between 0.1% and 0.2% in the visible spectrum. You can get it coated either both sides or one side. Use the one sided version, and coat a thin silver rich emulsion to the uncoated side. Dry, expose, develop. Then spray a layer of Barium Sulfate white reference standard (Kodak used to sell this, but you can make your own by ball milling high purity Barium Sulfate with isopropyl alcohol). Use a spray gun to spray on the backing layer. You then view the print from the front, the HEA coated surface will not reflect much light, and the gelatin has an index of refraction not too far from the glass, so you won't get much reflection there, the light will pass through the silver/gelatin layer, and scatter back from the ultra white backing. This is the optimal method of displaying in the reflection mode. I've been intending to do this using Dye Transfer instead of silver halide, but the principle is the same.

Regards - Jim Browning

Kirk Keyes
01-15-2008, 03:03 PM
This is here in apug just running with "3-dimensional look" in paper. I am impressed about the lyric textes and the descriptions about the feelings. I prefer, what I can measure.

Me too - that's why I started that thread.

01-16-2008, 01:21 PM
Well, engineers and figures...
I must admit though that sometimes I use figures too. But actually they all are of limited use. They can yield a means to compare films, papers etc. But the final standard would be man; who is known not be standard.
Thus next to granularity there will still be a term like graininess…

Concerning paper there are more features to name: weight, curl, haptic, smell…

Photo Engineer
01-16-2008, 04:30 PM


Tom Hoskinson
01-16-2008, 04:50 PM


Haptic, from the Greek (Haphe), means pertaining to the sense of touch.

Malaprop ???

Photo Engineer
01-16-2008, 04:55 PM
Thats Greek to me. :D I might have used tactile or some such. IDK.


01-16-2008, 05:15 PM

In German we (or rather designers) use `Haptik´, a noun, for the manner something feels like.
Of course it is one of these modern words, but otherwise I would have to use phrases as `the property to provoke tactile sensations´.

After posting I was not quite sure whether it is used in English too, but I was too lazy to check and to correct in case neccessary...

By the way, I got the impression that `tactile´ was used here in many threads in a weird way.

Anyway, to me `tactile´ is more related to the sensations someone gets than with the property an object hast got to arouse such sensations.

Photo Engineer
01-16-2008, 05:47 PM
Digital? :D


01-18-2008, 04:28 PM
Once I have seen the diagrams. This gamma distribution seems to be a quantum effect via sensitizer or dyes, depending on this, it can be minimized, when pictorial necessary, or enhance. Any minimal discontinuity (like low contrast resolution parts - the grain from a photographic wedge scale) interrupt this quantum effect.

When you look at the uneven development of negatives, special looking at the borders near the perforation:

1. Not enough movement is only a part of the truth
2. an equal great part (maximal the whole 24x36mm negative) has boarders with higher densities thanks the quantum-effect, when it is not chemically cancelled.

A friend told me today: When you enhance the quality of a paper (and you use not modern high resolution films with minimized grain), the (low contrast) grain becomes more visible. Enlargements from normal mix-emulsion grained 6x6 negatives to 8x10inch paper will -on thuch paper- suddenly looks more grainy. This happens in around ? 1984-88 ? with Kodak Polycontrast 3 from this production date. Later produced paper with that name had showned normal qualities.

01-28-2008, 11:02 PM
Well, I've been away for a bit, came back to see what's up with APUG, read this post (all six pages) kind of expecting to see something about obtaining a silver chloride paper, at least something about silver chloride coating recipe, but didn't see anything of the sort. Am I missing something with this post? Sorry if I am, just wondering if I've gone brain soft during my absence.