Silver Content, Rich Emulsions, super sensitivity

[Lenny Eiger]

Greetings all,

Is there any listing of different films based on silver content/richness/thick emulsion? I know some like the thinner emulsion film, but I am not among that bunch. In my process, a good, rich negative almost prints itself. The thin stuff drives me nuts.

In addition, is there any test for it? A test that would show sensitivity? Not basic ASA/ISO, but the ability to distinguish between two midtones? I imagine we could prove it by photographing maybe 10,000 patches and reading them all with a spectrophotometer to see if it doesn't show a change from one to another. But there has to be a better way....

I don't know, maybe I'm just looking for something with a really flat curve. How about a listing of film with the flat-est curves?

[sanking]

What ever do you mean by a"flat" curve?

Curves have toes, shoulders and straight line sections, but so far as I recall I have not hear one called flat. Do you mean one low in contrast?

[Kevin M Bourque]

No one really knows how much silver is in papers or films. As far as I can tell, terms like "silver rich" are just marketing.

If by "flattest" you mean films with a long straight line section, most modern elmulsions fall into that category.

[Bruce Watson]

I have to agree with Sandy and Kevin. Thick emulsion films were known for their large toe and large shoulders. Films like Kodak's Super XX had almost an "S" curve for a characteristic curve plot. Modern thin emulsion films have much longer straight line parts of their reponse curves. The longest and straightest characteristic curve I know of comes from 100Tmax.

On the other hand, if an old thick film emulsion is what you want, then that's what you want. There are some still being made. Check with the APUG forum - I'm sure they can point you in the direction you desire.

[Lenny Eiger]

The taller the curve, in the center straight line section, the more contrasty it is. If it was a perfect 45 degrees, that would be fine. If you look at a TMax curve, you will find that the gradient is much higher than 45. Midtone sensitivity is gone (I know this is a subjective statement) . People that use this film print more contrasty than I do, so it doesn't amtter to them. However, I am looking for something that doesn't start out contrasty, that has everything the scene had to offer.

[Jim_3565]

"On the other hand, if an old thick film emulsion is what you want, then that's what you want. There are some still being made."

No there aren't. Super XX was the last one. The "old style thick emulsion" claim is also just marketing hype.

You can easily verify this by attempting water bath development with any modern film. Success with water bath development was the hallmark of thick emulsion films. It does not work with any modern film, because this technique is a function of the physics of the emulsion and not the chemistry.

[John Kasaian]

Lenny,

Efke in definately different from any of the modern emulsions I'm familiar with. Whether or not its "old-style" I can't say, but it is different. Try it, you may like it (I do!)

[Ken Lee]

"The taller the curve, in the center straight line section, the more contrasty it is. If it was a perfect 45 degrees, that would be fine. If you look at a TMax curve, you will find that the gradient is much higher than 45."



I'm no expert, but doesn't the steepness of the curve depend on development variables: developer, time, temperature, agitation, etc. ?



Are you looking at the standard Kodak TMax curves ? Sandy and other list members can probably furnish many plots for other combinations of developer/temperature, etc.



An entirely subjective impression, but TMax 100 seems to have been created with greatest consideration to grain size. A "snappy" appearance may fully accord with its intended use. Other films exist, with more general applications in mind.

[Aaron van de Sande]

Efke was one of the first multi-layer emulsion films (in the 50s).

All of the single-layer films are gone, although the verdict is still out on j&c pro 100. Nobody seems to know how that film is really made.

[paulr]

" If you look at a TMax curve, you will find that the gradient is much higher than 45. Midtone sensitivity is gone (I know this is a subjective statement) . People that use this film print more contrasty than I do, so it doesn't amtter to them. However, I am looking for something that doesn't start out contrasty, that has everything the scene had to offer."

This isn't true, but more importantly it doesn't make any sense.

The angle of the gradient of t-max (or any film) is dependent on the degree of development. The angle is approximated by a measurement called Gamma. TMax is responsive enough to give you a ridiculously low Gamma (or a ridiculously high one) if that's what you're looking for.

I have never heard of "midtone sensitivity" so I can't comment on that.

I don't believe you can generalize that people who use TMax print at any particular level of contrast. It's a responsive emulsion; I've used it for years but I cannot identify its use in other people's work, because there are so many variables and because it yields different results with different kinds of development.

In general, it does have a longer straight line section than most traditional emulsions. Maybe this is what you're seeing. It seems to me to have a very short toe, at least when developed the way I develop it. This, however, lends a sense of open shadows and lots of range in the midtones, not one of high contrast.

This has nothing to do with the amount of silver. As Kevin pointed out, "silver rich" has always been a descriptive phrase used by photographers, or a marketing hook used by manufacturers. There's never been any reccord of how much silver is in any of this stuff, or even of what difference it might make. Any film has enough silver in it to get impenetrably dark.

There may not be any true thick emulsion films, but there are older technology films that tmax. Anything besides tmax, ilford delta, and whatever fuji's similar product is.

But I'm willing to bet that with some work with developers, you could get a tonal scale you like out of just about anything.