maximum density of negative

alanrockwood · Apr 17, 2018

First let me say, my question is not "what is the dynamic range....?" If you want to talk about dynamic range go ahead, but my question is, what is the maximum density of black and white negative film? By "maximum density" I mean what would a densitometer read off the film when the film is the darkest it can be. This is total density, i.e. not subtracting off base plus fog. One can also limit this to pictorial-type film such as Tri-X, not specialized film materials such as microfilm.

This is a technical question, not an artistic question or a question about exposure or development, other than that the exposure and development should be that which would give the densest negative in the most highly-exposed regions.

My wild guess is that the maximum density might be somewhere in the neighborhood of 3.0 or possibly a little higher.

I have the same question about Velvia, assuming minimum exposure and normal development, but maybe I should ask about Velvia somewhere other than in the black and white category of threads.

Thanks.

Anon Ymous · Apr 17, 2018

Depends on the film itself, developer used, development time, and possibly other factors. Your "in the neighborhood of 3.0 or possibly a little higher" figure is low. For example, the TMax 400 datasheet has characteristic curves for several developers and times, and the one for T-Max RS clearly reaches 3,5 for 9', without showing significant shouldering, the actual Dmax is higher. Likewise, the Velvia 50 datasheet shows maximum densities for the R, G and B channels, with the red one having a Dmax of ~3,8.

removed account4 · Apr 17, 2018

no clue what the #'s are, but but ive had some pretty dense ones ... took about 13 seconds with a 300 watt bulb to contact print
on a sheet of RC paper. couldn't even see the image on the film back-lighting it with a bright flash light...
prints came out beautiful ... one ( a little less dense, less than 10 seconds printing ) is in the gallery right now.

Neil Grant · Apr 17, 2018

About 3.0 sounds plausible for Tri-X. I finer grian fillm wold be capable of a higher D max - the 'grains' fit together more tightly. Why do you need to kow this?

Mr Bill · Apr 17, 2018

The only hard info I recall with "excessive" density was published circa 1990 in a Kodak publication called "Tech Bits." Back then the Tmax films were fairly new, and the author wanted to see if they could record a luminance range of over a million to one, as some prior kodak films had. So he included some sets of curves showing that they could. In these curves, Tmax 100 showed density exceeding 3.5 (I checked to be sure). My recollection is that Tmax 400 ran up to about 4.0 density (I'll try to find a copy if it's important to you).

My fuzzy recollection is that pro grade densitometers of the day would only read up to about 4.0, so might be hard to find any higher readings. Also, with such high densities there is such a small amount of light to read that leakage around the densitometer's snout could be an issue, giving a lower density reading. (Most densitometers are probably fairly old by now, and the rubberized black seals around the snouts are often deteriorated.)

John Salim · Apr 17, 2018

..... just measured a fogged ( tongue ) from a 35mm Fuji Acros 100 film pushed one stop which gave a reading of 4.09 if that helps ?

John S

Bill Burk · Apr 17, 2018

In the graphic arts Kodak film regularly gave 4.0 densities. Other brands came close, like 3.6 or so.

Velvia and other slide film is transparent to infrared, so you might read a high density but don’t look at the sun through it.

My usual tests come up to around 2.2 or so with a normal extent of development

alanrockwood · Apr 17, 2018

Neil Grant said:
...Why do you need to kow this?

I am contemplating and idea, and it would depend in part on have at least some light being transmitted through the most dense part of the negative.

Herzeleid · Apr 17, 2018

Using 1 stop overexposure and %10 extended development in rodinal, I was able to achieve LogD 2.8. It was a sunny outdoor image for testing maximum densities. In case I plan to contact print negatives for salt print.
Copper sulfate-Potassium Bromide bleach followed by silver nitrate intensification will double that. Yep, LogD 5.6 , I cannot see the beam of my flashlight through that.

ic-racer · Apr 17, 2018

alanrockwood said:
I am contemplating and idea, and it would depend in part on have at least some light being transmitted through the most dense part of the negative.

log d 5 = ND5 = 16 2⁄3 stops = 0.001% transmittance

alanrockwood · Apr 18, 2018

From the responses so far I am coming up with two main concepts. Under relatively normal illumination/exposure (including those parts of the negative that received the highest dose of light) and relatively normal development the maximum density tends to not exceed 3 for a film like Tri-X. Under extreme conditions of exposure and development the density can be much higher than this.

Does that sound reasonable?

Bill Burk · Apr 18, 2018

Sounds right.

Hey alanrockwood you know density adds up. If you put two pieces of film on top of each other, and each has a 3.0 density. The two add up to a density of 6.0

Not sure what you are planning, but that might come in handy.

alanrockwood · Apr 18, 2018

Bill Burk said:
Sounds right.

Hey alanrockwood you know density adds up. If you put two pieces of film on top of each other, and each has a 3.0 density. The two add up to a density of 6.0

Not sure what you are planning, but that might come in handy.

Thanks for the comment. Yes, I know how density adds up. It's basically the same as what as known as the Beer-Lambert law in spectroscopy. Absorption (basically density) is additive. Transmission is multiplicative. The reason is the logarithmic relationship between density and transmission.

Mr Bill · Apr 18, 2018

alanrockwood said:
Under relatively normal illumination/exposure (including those parts of the negative that received the highest dose of light) and relatively normal development the maximum density tends to not exceed 3 for a film like Tri-X.

I'd guess that Tmax 400 is probably not too awfully different from Tri-x; the attached graph for 1990 Tmax 400 will show more than I'm willing to try typing (wink).

Note that this graph shows a rather wide exposure range compared to those normally published; for general information each f-stop exposure difference is about 0.30 on the log exposure axis. Meaning that this graph shows an exposure range of about 20 f-stops (20 x 0.30 = 6.0 log exposure units).

Note: in the original article, Kodak "Tech Bits" (1990), it is mentioned that the graph is only plotted up to density = 4.0; this does not mean that the film was so limited.

David Lyga · Apr 18, 2018

David Vestal, in his 'The Craft of Photography' did a test seeing how much overexposure Tri-X could have without image deterioration. He published the results in his book. He got down to an EI of about 6 and STILL there was no image deterioration. That is six steps more exposure than box speed indicates. After that, the image finally started flattening out. Now, Tri-X is unusually forgiving, but with most films even gross overexposure (without over-development) will yield high quality results. I am one who does not see a grain increase (or resolution problems) with overexposure, only with over-development. - David Lyga

Old-N-Feeble · Apr 18, 2018

Don't forget that density is added with chromium intensifier or selenium toning.

Saganich · Apr 18, 2018

I just measured the densest TriX end piece I could find using my MacBeth TR524. Result 2.76. That was 10 minute development time in D23 stock.

John51 · Apr 18, 2018

Bill Burk said:
Sounds right.

Hey alanrockwood you know density adds up. If you put two pieces of film on top of each other, and each has a 3.0 density. The two add up to a density of 6.0

Not sure what you are planning, but that might come in handy.

Just to clarify, if I took a bracketed series of blank shots, ie. exposure but no detail, I could stack the negatives to give me the nd I want.

Adrian Bacon · Apr 18, 2018

Many bw films can get quite dense with the right developer and enough development time.

I once had a frame of TMAX 400 in 120 roll where I accidentally tripped the shutter on the camera from a jostle. The aperture was set at f/4 and the shutter was 1/30. It was in the middle of the afternoon during the summer, easily 7-8 stops over exposed. I developed the roll normally and figured that frame was going to be a throwaway. It came out of the fixer black as night, I couldn’t see through it, much less tell what it was a picture of.

I put it on my DSLR scanner that uses a strobe as a light source, and after dialing the strobe power up quite a bit higher than normal actually got an image, and shockingly, it looked like it was all there, just really super dense.

ic-racer · Apr 18, 2018

Not sure what you are planning but I needed a tiny ND filter to re-calibrate a simple flash meter. Rather than calculating and making the correct density, I just sifted through old control strips in the trash pile until I found the exact density I needed. The resulting ND filter worked perfectly.

Bill Burk · Apr 18, 2018

John51 said:
Just to clarify, if I took a bracketed series of blank shots, ie. exposure but no detail, I could stack the negatives to give me the nd I want.

Sure, it's not going to be a quality image forming light path (so you won't want to do this to make a "filter") but densities add up that way.

Photo Engineer · Apr 18, 2018

A density of 3.0 to 4.0 is the norm.

PE

Luis-F-S · Apr 18, 2018

So why don’t you develop an overexposed strip of film and read the density and tell us what you find?

I get with Kodak TMX 5052 135 leader strip a 3.16 density with both an X-Rite 301 and an Ihara T5 densitometers. Developed HC-110 Dil B.

alanrockwood · Apr 19, 2018

Luis-F-S said:
So why don’t you develop an overexposed strip of film and read the density and tell us what you find?

I get with Kodak TMX 5052 135 leader strip a 3.16 density with both an X-Rite 301 and an Ihara T5 densitometers. Developed HC-110 Dil B.

I'd rather not reinvent the wheel if I don't have to. Thanks for posting your findings.

maximum density of negative

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