Diffuse rms Granularity & Image Structure

[RAP]

I recieved the specs for the new line of Kodak B&W films and I am stuck on a term, "Diffuse rms Granularity" which uses a number as an indicator. Question; the smaller the number the smaller the grain or the larger the number, the smaller the grain?

T-MAX 100 has a number of 8, T-MAX400 a number of 10, TRI-X a number of 16. I assume that the smaller the number, the smaller the grain but would like to know for sure.

Thanks for the help.

 

[Thilo Schmid]

RAP,
There is a good explanation availiable in the Motion Picture Section of the Kodak Website:
http://www.kodak.com/US/en/motion/students/handbook/sensitometric6.jhtml

 

[RAP]

Thanks for the link. I read it but it does not answer the basic question of the smaller the # the smaller the grain, or visa versa? I know with fishing, the larger the #, the smaller the hook so I am just looking for a clarification.

The reason I am going through all this is because I am down to my last 20 sheets of old TRI-X and I am faced with the dilemma of testing out the new and it is driving me crazy! I hate it when Kodak changes things!

I have been a TRI-X/HC110 man for years and I know how to work it.

I am also considering other developers such as XTOL and MICRODOL-X with the new TRI-X.

 

[Thilo Schmid]

RAP,
the RMS value is a direct indicator of the recorded "noise level" which is supposed to be equal to the graininess of the film. The higher the noise level (i.e. the larger the RMS value), the grainier does the film appear.

TP in Microdol has a RMS value of 5 whereas TMZ has a RMS value of 18

 

[Tom Duffy]

RAP,
you may not be able to get the new Tri-x in sheets, yet. I just bought 2 boxes of 5x7 and 1 of 8X10 from Calumet and it's still the old stuff. 35mm is now becoming available.

by the way "Photo Techniques" has a good article on the new kodak films in the March/April issue. Testing shows the new Tri-x to have finer grain than tmax 400.
Tom Duffy

 

[RAP]

I believe I saw it already but I will look at it again. Thanks!

Anybody have experience with Microdol-x? I have been reading the Kodak specs and they say it leaves the film with a slightly brownish image tone. This leads to believe that it may have similiar qualities to pyro.

Any thoughts?

 

[lee]

I don't think microdol-x is that similar to any PRO developers I know of. I have used microdol-x with several films and I have never seen a brown stain of any density. In my mind, microdol-x is really d-25 or if not it is a very close cousin.


lee\c

 

[Goldfarb]

I haven't used Microdol-X in ages, but it's nothing like pyro. I believe it is also similar to Perceptol--good for fine grain at the expense of some speed.

 

[Tom Duffy]

RAP,
Microdol is like the anti-pryo! to provide very fine grain it disolves the edges of the physical silver in the film, and costs you a stop of film speed. Makes any film appear less sharp than it could be. Pyro has the opposite effect, that is, it makes the film appear sharper than is possible with a conventional developer. If I wanted less grain, I'd use a finer grain film.

What format are you using? In 35mm tri-x, I like HC-110 or D76 1:1. in medium or large format, I would use TXP. I'm starting to like Pyrocat HD. In my first comparisons with Rollopyro, the pyrocat is at least as good, with no uneven staining issues. My contact print times for TXP are about half those of Rollopyro.
Tom

 

[RAP]

I shoot 4x5 almost exclusivelly and I am making decisions based on that. I have settled on Ilford Pan F Plus in DDX (since the demise of Agfa 25) for 120 and 35mm which I ocassionally shoot.

I may going to run some tests between TRI-X and Ilford HP5. TRI-X in HC110 and HP5 in DDX on the same subject and pyro for both and see what happens.

Since Microdol smooths grain edges, then sharpness will suffer, so I will abandon that avanue.

Tom, you mentioned that the new TRI-X has finer grain then TMAX 400, that sounds very promising. Maybe I will stick with what I have for years, TRI-X and HC110. I will post my results.

Thanks all for the input!

 

[gainer]

The brownish tint is an indication of fine grain. I think it is like the refractive effect of a line grating.

Pat Gainer

 

[fhovie]

Tom, you mentioned that the new TRI-X has finer grain then TMAX 400, that sounds very promising. Maybe I will stick with what I have for years, TRI-X and HC110. I will post my results.

Thanks all for the input!

I really like TRI X but I have a hard time imagining that it could be finer grain than TMAX because of the shape of the grains and the structure of each film. I find TMAX to be very contrasty and not as compression or expansion friendly as I would prefer, other than that it is very fine grain. Did Kodak make this claim?
Frank

 

[Tom Duffy]

Frank,
no it was written in the aforementioned Photo Techniques article, written by two former film development people at Kodak. They also claim that Tri-x roll film, over time, has become more straight line than it was. They tested only roll film. TXP was not tested.
Tom