Learning processing with the aid of a densitometer

[Steve McLevie]

Hi all,

I've just purchased some FP4+ with also some Pyrocat HD. I'm new to testing and I would like some pointers.

Equipment:
Jobo Expert 3006 drums.
4x5 sheets of FP4+
pyrocat HD
TF5 fixer
water stop
5 mins pre-soak (lots of black inky water at the end which scared me quite a bit!)
4 mins in fixer
demineralised water all round
big plastic tub in which I have an aquarium heater and aquarium water pump
digital thermometer
no sulphites
4 to 6 rpm constant rotation in about 2 or 3 inches of water at 20C.

I've done two tests now to determine development time @ 20C.

The first was for 8:15 mins (80 ISO) and the second was 8:45 mins (64 ISO). The results are not that different.

I have a film base + fog of 0.1 and 0.11 on the 361T.
The Zone 1 exposure is 0.17 and 0.18.
Zone 5 exposure is 0.6 and 0.61.
Zone 7 is 0.87 and 0.86.

Q1. Do these figures sound right ? Its my first ever try at using the densitometer.
Q2. What am I able to expect ? Can I think that if I increase the development time that my negatives can approach a maximum density of some sort ? I read somewhere that FP4 can achieve 3.2 density ?! I'm a long way from that ! I'm thinking that I should increase development until Zone 5 gives me 0.72 or so on the densitometer. Is this a correct goal ? I'm interprreting an Ansel Adams graph in The Negative for this assumption...

I'm not going to be chemically printing in a hurry. The only option I can see is for a digital workflow from here on in.

My impressions of my work from before the densitometer is that I've not had very contrasty negs. The second test included a Zone 11 shot with a density of 1.3. Still nowhere near any 2 or 3 ...

At this stage I'm thinking of another test at 64 ISO and I'll develop for 11 minutes.

Advice and energy keenly sought !

Steve

[erie patsellis]

You really need to slow down, establish your EI first, then establish your processing time for a CI of approx. .8 to .9 (I found that for my scanners that's the ideal contrast index, while still allowing a decent optical print to be made if desired)

our EI of 80, which resulted in a zone I density of .7 over fb+fog is a little thin, you may want to try the same processing times, but at an EI of 40. Once you establish your EI (as indicated by the zone I density of .1 over fb+fog), then adjust your processing time to get your Zone VIII to be ~.8 (or whatever CI you standardize on) above your Zone I density.

I don't use FP4, nor pyrocat, so I have no idea if your numbers are even close. When shooting TMY, I place my shadows on zone III or IV, as TMY has a pronounced knee in the lower densities and a long straight curve and it seems to go on forever (not really, but for quite a few stops). By placing your shadows higher, your entire image is in the linear portion of the curve.

There are several good books that outline the steps needed, if Adam's "The Negative" is too intense for you, there's "Beyond the Zone Syatem", Fred Picker's Zone VI workshop as well as others I'm sure.

[ic-racer]

Hi all,

I've just purchased some FP4+

(80 ISO) and the second was 8:45 mins (64 ISO).

The Zone 1 exposure is 0.17 and 0.18.

I'm thinking of another test at 64 ISO

?

You would want to increase the exposure index with those findings. Shoot for a Zone I of 0.10 log D.

In terms of the higher zones, I'd make some prints and zero in on the contrast (development time) that way. Once you get the contrast the way you want it you can document where your higher zones fall and use that for future reference.

[Jay DeFehr]

Hi Steve,

Sandy King is the expert on Pyrocat HD, FP4+, and the 361T, so you're starting down a well trodden path. Until Sandy comes along, I'll suggest you first determine your negative density range and CI for your scanner and printing process. Your EI must be determined in conjunction with your CI -- in other words, film speed and contrast are correlated, and more contrast will generally correlate to more film speed.

Also, it's important to indicate which densitometer filter you're reading your negs through. If I recall correctly, the 361T is a UV densitometer, and you can expect much different readings depending on which filter you use, due to the image stain. UV readings are most appropriate for UV printing processes, and a blue filter for graded silver papers, but white light might be best for scanning (ideally, you'd want to match your densitometer light source to the light source of your scanner).

I highly recommend the BTZS system and the Winplotter SW for this kind of testing.

Good luck!

[Leigh]

5 mins pre-soak (lots of black inky water at the end which scared me quite a bit!)

That's just the anti-halation dye dissolving. It's normal.

The dye is applied to the back of the film.
It prevents light from going through the film and bouncing off whatever is behind it.
Such reflected light would cause additional out-of-focus exposure, which is not desirable.
The dye is soluble, and normally comes off during the first processing step.

All modern films have anti-halation dye with the exception of some infra-red films.
IR films with no AH dye are noted for creating a "halo" effect around highlights.

- Leigh

[Steve McLevie]

Thanks guys,

This is quite daunting I must admit. There is precious little on the net that seems congruent and is well stated. Much is confused ramblings and self-contradictory. I am just starting out with this and maybe its the way I learn but I seem to not get a few things eh !

I just found a link to a Kodak "Basic Photographic Sensitometry Workbook" given by none other than our ic-racer on the APUG forum ! Excellent. Kodak are quite concise. Now I know what CI is .... its the slope of the density curve.

My tests show I'm 0.07 above FB at Zone 1. This shows I need to either or both increase exposure or increase development. I don't want to drop the film speed down any further than 64 at this stage so I'll need to increase development to achieve a Zone 1 density of around 0.22.

I guess my second question is asking whether I can expect the film to develop to a max density reading (D-max) in the 2's and possibly even a 3. Does FP4 and Pyrocat-HD go that high ? Perhaps I should leave a sheet out in the sun !

I'm not printing traditionally guys ! I assume that means I should try to get a good spread of contrast in the negative. Any pointers as to the best CI for scanning ? I am going to shoot for a density of 1.9 at Zone 11 as a minimum. Erie you suggest Zone 8 should be 0.8 above FB ? ie 0.9. (I'm getting a Zone 8 of 0.95 now @ 80 ISO !) The Ansel Adams book has a curve showing a normal dev with a density of around 1.35 for Zone 8 (Tri-X admittedly).

I think I should only use the UV setting on the densitometer for all readings because it is a staining developer (?).

Although I appreciate there can be differences between machines in the workflow I don't quite agree with the idea that one has to find one's own settings. Surely FP4 in demineralised water at 20C developed with the same time measurement called seconds at sea level with the same chemical concentrations is going to be within the bulls roar whether I do it in South America or in India ! If things were that variable as some attitudes suggest there could be no real photographic processing industry ! (Attitudes not seen in this thread mind you ...)

Thanks again for the replies.

[Leigh]

There is precious little on the net that seems congruent and is well stated.
Much is confused ramblings and self-contradictory.

That's true of any subject you research on the 'net.

I guess my second question is asking whether I can expect the film to develop to a max density reading (D-max) in the 2's and possibly even a 3. Does FP4 and Pyrocat-HD go that high ? Perhaps I should leave a sheet out in the sun !

One thing to be careful of.

Whenever you're developing test film, make sure the exposure of the total film(s) represents normal scenes.
This avoids developer exhaustion that can occur if the average density of the films is much higher than normal.

As an extreme example, you could develop three sheets of film together in the same batch,
one completely unexposed, one exposed for middle gray, and one fully saturated (exposed to the sun).

Also, when doing test processing, make sure you have developer at full strength.
For example, Rodinal wants 10ml of concentrate for every 80 square inches of film.

=====

If you want something with good D-max, shoot Fuji Acros. It's my standard 4x5 film.
I don't think you can blow the highlights even if you try.

- Leigh

[ic-racer]

Ok, I see you did not subtract the base density from the Zone 1 values listed. I usually zero the densitometer on the film base.

Seems like you have the basics down.

I might suggest using the contrast index or slope rather than a set Zone value for checking your development time.

Each time you change your exposure index your high zone value changes, even when you don't change development (that is why that method is not listed in that Kodak workbook). Whereas the slope or contrast index is independent of your exposure index rating.

[Steve McLevie]

Cheers guys,

I'll test again but this time I'll try to get some serious slope happening. Possibly straight to 13 mins development.

The reason I said I don't want to rate the film any lower than 64 ISO is because of the grain that will come into the images. My happiest ISO would probably be 80 actually.

I notice I've purchased some sulphite in the past ... I may even start a round of testing with a small pinch of that in the mix too.

I'm very happy to have used three new items to me and get something meaningful - the drums, the film and the developer.

Cheers again !