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View Full Version : Densitometer Numbers - What they Mean

Renato Tonelli
4-Jun-2007, 19:56
I just finished testing Trix-X and Fuji Neopan 100 Acros for Zone I (E.I.) and I am very happy with the results (I think); Tri-X is almost twice box speed and the Neopan 100 tested at full speed (XTOL 1:1 for the Tri-X and XTOL full strength for the Fuji).
Now I am testing for Zone VIII and may not have time to do test prints as I am about to leave on an extended trip. Other sources have suggested using a densitometer to help me determine the development time as mentioned by A. Adams in "The Negative". Basically, it says that the Zone VIII negative should fall between 1.25 to 1.35 (after subtracting the fb-f). My first Zone VIII test is 1.65
Am I correct to assume that I need to reduce development? And by how much - is there a mathematical/logarithmic correlation that could guide me? I have not been able to glean an answer from my usual sources; hopefully someone here will set me on the right path.

steve simmons
4-Jun-2007, 20:03
I like a density of 1.35above fb+f with PMK and Gordon Hutchings likes a density of 1.6 or a little above with PMK. Of course, with a staining developer blocking high values is much less likely.

steve simmons

Renato Tonelli
4-Jun-2007, 20:07
That was quick! Thank you for the advice.

fhovie
5-Jun-2007, 23:53
Wow - dense! (if you want 10 zones) - what does you paper do?

My grade 2 paper gives me a zone 1 at .1 over B+F and a zone 10 at 1.25 over B+F.
I guess the real question is:
Do you want all ten zones or are you doing expansion?
of course another good question would be:
What is your papers response to density?

I (as a mater of choice) try to fit my Scene Brightness Range (SBR) into what Density Range (DR) my paper of choice will print.

My paper of choice is grade 2 fiber - Forte Fotenza for now - it will print a DR of 1.25

So I make my negs have a DR of 1.25

That puts zone 3 at about .35 and zone 8 at about 1.0 - IF I want to print 10 zones.

If my scene is only 5 zones than I want zone 3 at .1 over base fog and zone 8 at 1.35.

Just some food for thought

photographs42
6-Jun-2007, 06:34
I’m skeptical of your Tri-x test of double the rated speed. I used Tri-x 4x5 and 5x7 for about 25 years in HC 110 and Tri-x and Xtol 1:1 for several years and my E.I. was 160 for both. Your post indicates a rated speed of 640!!!

Jerome

hmf
6-Jun-2007, 07:00
I like a density of 1.35above fb+f with PMK and Gordon Hutchings likes a density of 1.6 or a little above with PMK. Of course, with a staining developer blocking high values is much less likely.

steve simmons

Is it appropriate density of a PMK negative to that of a non-staining film developer? My understanding is that the amber color of PMK lowers the effective contrast of the negative, especially for VC papers.

Jorge Gasteazoro
6-Jun-2007, 08:31
I just finished testing Trix-X and Fuji Neopan 100 Acros for Zone I (E.I.) and I am very happy with the results (I think); Tri-X is almost twice box speed and the Neopan 100 tested at full speed (XTOL 1:1 for the Tri-X and XTOL full strength for the Fuji).
Now I am testing for Zone VIII and may not have time to do test prints as I am about to leave on an extended trip. Other sources have suggested using a densitometer to help me determine the development time as mentioned by A. Adams in "The Negative". Basically, it says that the Zone VIII negative should fall between 1.25 to 1.35 (after subtracting the fb-f). My first Zone VIII test is 1.65
Am I correct to assume that I need to reduce development? And by how much - is there a mathematical/logarithmic correlation that could guide me? I have not been able to glean an answer from my usual sources; hopefully someone here will set me on the right path.

Yes, you should reduce development. There is not an algorithm that will give you a correlation as the film curve is not linear. You might try using the slope of the curve but then it becomes to difficult to explain.

Your "working" densities (in other words the densities described by Adams) should be fit to the type of paper you are using. Most silver papers will not tolerate a spread or range greater than 0.9 or 1.0 with the exception of AZO of course. The problem with Adams' "recommended" values is that they were made for the papers of his time, and a that time they were able to "accomodate" a greater range than present papers.

You should have for Zone I a 0.1 value above b+f, so your zone one value with the b+f should fall around 0.15-0.2. Add 0.9 to this and your Zone VIII value should fall around 1.0 to 1.1.

This values are for Grade 2 paper, if you are using variable contrast paper then you can get away with a more contrasty negative but will most likely have to do some acrobatics in the darkroom to get a good print.

Good luck.

Leonard Evens
6-Jun-2007, 11:27
The point is to get the negative to fill the range provided by the combination of the paper you use and the enlarger you use. Enlargers with condenser lighting produce higher contrast thaan those with diffuse lighting. The only way to do it is to experiment. You could start off with a step wege which you print with your enlarger. Measure the densities in the step wedge and see how they come out in a print. The density that produces what you think is appropriate for Zone VIII in the print is what you should be aiming for as Zone VIII in your negatives.

steve simmons
6-Jun-2007, 12:37
"The density that produces what you think is appropriate for Zone VIII in the print is what you should be aiming for as Zone VIII in your negatives. "

What is zone 8, compared to what, at what proof time???????

This statement doesn't really say anything at all and what are you trying to say?

Without doing some testing you are swatting at flies. Yo need an anchor.

If you have a densitometer use it. If not, do the testing as described by Fred Picker in his book The Zone VI Workshop and a discussed many times on this forum and on the View Camera web site

www.viewcamera.com

then go to Free Articles

If you use a grade 2 filter or no filter, your densities will come out as many of us have suggested.

steve simmons

Leonard Evens
7-Jun-2007, 08:16
Since Steve objected to what I said, let me try to explain it further. Adams envisioned that each zone from should produce in the print a certain level of gray. If you had a reflection densitometer, you could in principle measure these reflection densities under stardarized lighting conditions. But Adams explains in his books how to judge visually how each of his zones should look in the print. Since you are unlikely to be using a reflection densitometer for the print, you should rely on visual inspection as recommended by Adams.

When I say density, I mean of course density over some base, which is the way you have been using that term.

Now there is a functional relationship between the transmission density in the negative as measured by a densitometer---which you do appear to have---and the level of gray in the print. This depends of course on the enlarger, the type of paper you use and how you develop it, but we assume you standardize all of those variables. It also depends on how much exposure you use when you print, but you can can adjust that so that the print goes from deepest black to complete white and each zone appears as the appropriate level of gray. Having done that, the laws of physics and chemistry will assure you that each specific density in the negative will produce a certain level of gray in the print. For example, you may discover that a film density of 1.25 produces a level VIII gray in the print. You want to adjust the ISO rating at which you expose the negative and the way you develop it so that what you envision as a level VIII in the scene produces a density in the film (under your standardized conditions) of 1.25. But someone else may find that under his conditions a 1.15 in the film is needed to produce a level VIII gray in the print. His advice to you would not be too useful. You have to find out for yourself what works under your conditions.

There are lots of sources of information on the subject starting with Adams. Adams started from basic physical principles and adapted them to the materials he had available at the time. A lot has changed since then. I can't tell you which of the many references will make the most sense to you. Even after you understand it all in principle, applying them in practice can sometimes be confusing. Certainly look at everything you can, including where Steve suggested, but in the end, I think you will have to experiment as I, and several others, have suggested.

John Berry
7-Jun-2007, 22:21
The answer to your question is in the test prints. ( paper testing should have been done first) What does the PAPER say. I agree with the rest that a DR of 1.0 will let you have somthing usable but maybe not the optimum.

Renato Tonelli
8-Jun-2007, 19:26
Paper testing is all day tomorrow and possibly Sunday if need be. I wanted to develop several negatives at different times so that I would not have to set up for printing each time I finished one set of tests.
I would also like to thank everyone who taken the time write (and) may continue to write.
I have my darkroom in a college and my colleagues are starting to poke fun: "Zone what?" , What are you shooting? the negative looks blank!" "Why don't you just shoot stuff!", not to mention the inevitable and ever present: "Haven't you heard about digital photography?" The only comic relief came from the puzzled looks on people passing by Park Avenue as I was shooting the black and white card - Ahh... the sacrifices we are called upon to make for the sake of our art/craft...

John Berry
9-Jun-2007, 00:07
Good Idea to do different times at once. It will save time. Do you have a step wedge to do paper testing? That makes it a lot easier.

Renato Tonelli
9-Jun-2007, 03:52
I do have a step wedge and since it will be the first time I'm using it, I expect that it will be slow going until I get the hang of it. The last time I did these tests was in the early 1990's and I followed F. Picker's instructions to the letter. When Kodak introduced the slightly altered Tri-X emulsions I didn't bother testing, figuring that it would be "close enough" - I was wrong. For the new round of testing I decided to use XTOL for various practical reasons.
In retrospect, I almost wish that I had not tested the Fuji 4x5. I generally like to stick to the same materials (Film (Tri-X)/Paper/Developer) but the ability to use quickloads was very attractive.

fhovie
10-Jun-2007, 19:23
I had taken some shots with some prototype film and was using the "recommended developer and time and got really cooked negs. I was measuring low base fog and zone 9 was up around 2.5 or more. I got out some FB VC paper and put down the Stouffer step wedge and put in a 1/2 grade filter and what do you know, the paper printed all the tones on my cooked neg. Of course, half the image was in the shoulder and the image was quite lith like but it was very telling of the use of a densitometer and step wedges while printing. My standard processes are set and evaluated with them. New papers get the step wedge so I know what a neg will need to print on it. I look at my negs regularly and make small adjustments to future development times to get the range I want.

steve simmons
10-Jun-2007, 20:19
What is some prototype film?????

If you are using a 1/2 grade filter and getting lith like images you are way overdeveloping your film.

For the life of me I can not understand why people buy off the shelf products, follow the mfg. directions and then wonder why their results are not very good.

Simple testing is so easy and in the long run a real time saver.

steve simmons

fhovie
11-Jun-2007, 08:39
Prototype film is when a manufacturer gives you free film to test that has not been released on the market. (AND they do not want you to discuss the specifics) Following their instructions with their chemistry cooks film - at least when exposed in this part of the world this time of year - (which might make sense if consider it is not ordinary film). I followed their instructions to honor their request that came with the prototype film. So:
I did not buy off the shelf products
I followed their instructions at their request
The results told them what they wanted to know.

As for me, I only mix my own chems - my processes produce predictable results within the measured range of densitometry that I desire for the papers and enlarger I use. AND this was the first time I EVER used that filter - normally I only use GRADE 2 FB paper.

steve simmons
11-Jun-2007, 08:42
Prototype film is when a manufacturer gives you free film to test that has not been released on the market. (AND they do not want you to discuss the specifics) Following their instructions with their chemistry cooks film - at least when exposed in this part of the world this time of year - (which might make sense if consider it is not ordinary film). I followed their instructions to honor their request that came with the prototype film. So:

So, then why are you discussing this publically?

steve simmons

fhovie
11-Jun-2007, 09:30
Geee Steve: It is my work - I did not say who or what or what the outcomes were - it could be anything - anywhere - anyone. So as far as you would know it is all anecdotal. I am a subscriber and I don't remember whizzing in your corn flakes - you know the decaffeinated brands really are not that bad.

steve simmons
11-Jun-2007, 10:46
I don't remember whizzing in your corn flakes - you know the decaffeinated brands really are not that bad.

I asked a reasonable question. Apparently you are testing a product that has not come to makret and one that the mfg or distributor does not want made public yet. You can't tell us what it ai, or anything else.

IMHO you were probably expected to keep quiet about your testing. This is the usual protocol.

steve simmons

fhovie
11-Jun-2007, 11:30
Just looking at the thread here Steve, I mentioned a circumstance where I had unruly negs and was able to print using a step wedge - all on topic and with no breach of agreement.

"What is some prototype film?????

If you are using a 1/2 grade filter and getting lith like images you are way overdeveloping your film.

For the life of me I can not understand why people buy off the shelf products, follow the mfg. directions and then wonder why their results are not very good.

Simple testing is so easy and in the long run a real time saver."

So I gave a little more info that I am not incompetent and gave a reason why I was faced with these cooked negs and got from you:

"So, then why are you discussing this publically?"

And of course now

"IMHO you were probably expected to keep quiet about your testing. This is the usual protocol."

And all this time I have my agreement which has been adhered to - I only shared what I did to make a point about using a step wedge to print a difficult neg. No details of who what why when where or how have been discussed - nor images and comparisons. Only the anecdotal information that is on-topic with densitometry.

So -
I agree with you that manufacture recommended times and off the shelf chemistries will more often than not cook a neg.
I will be allowed to discuss those other things some time if I care to. None of that was ever the point - I only mentioned the word "prototype" to explain why I had a cooked neg. The discussion (for me) was always about densitometry and step wedge use and where it comes in handy. The other information was only just enough to explain why the situation occurred. The "testing" is quiet. Yes - somewhere there are companies that make film - at any given time some of them may try something and the product may never come to market. And sometimes there are things learned from that testing that have nothing to do with details of the testing. All of which might be the case here and it doesn't require things like "you are way overdeveloping your film.", "For the life of me I can not understand why people" "you were probably expected to keep quiet"

Geepers! I don't know about your "usual protocol" I have an agreement that is adhered to in full.