Using a densitometer on a pyro developed negative

[Alan9940]

Hello All,

Just recently got a Gretag D 200-II densitometer for some film testing. When using conventional developers (D76, HC-110, etc), I always shot for about 0.10 over fb+f for a Zone I density, and 1.25 - 1.35 net density for Zone VIII. Should I expect the same numbers for a pyro-stained negative? Per Sandy King's suggestion, I'm using a dark blue (Wratten #47) filter in the light path to simulate the paper's response to blue light. Also, I generally print on VC paper for enlargements and chloro-bromide papers, such as Lodima, for 8x10 contact prints.

Any insight regarding proper Zone I and Zone VIII net density for a pyro-stained negative would be very helpful. Don't know if it makes any difference, but I usually use Pyrocat-HD.

Thank you.

[Jim Noel]

Over time there have been several threads dealing with this issue.

[Alan9940]

Over time there have been several threads dealing with this issue.

If there are some archived threads, I must not be using the correct keywords to find the information. I open to suggestions...

Thanks!

[Alan9940]

I found an article on Unblinking Eye that talks about reading a step wedge in UV, Red, Green, and Blue and translating that to...I guess...a standard B&W negative. From what I can gather, it appears that since I'll be effectively using my densitometer in "blue mode" to read densities, for Zone VIII I'd need a reading something like 1.1 which + the stain density (I have no way to read stain density) would equate to a standard negative density of about 1.25 - 1.35. Does this logic make sense? It would be very helpful to me if someone could confirm my estimated Zone VIII density value.

Thank you.

[Erik Larsen]

I believe If you are printing silver gelatin just use the readings you get in visible mode, if you are printing with uv light for alt processes you're out of luck unless you have a uv channel on your densitomiter. I've never gotten reliable results with a blue channel reading compared to a UV channel for calibrating for alt processes but that could be my ignorance at fault.

[Steve Sherman]

Hopefully I can offer some practical real world experience to your pyro questions

I have an ordinary transmission densitometer with no capability of reading UV densities, doesn't even have RGB channels. I regularly designed my neg highlight density to be .9 - 1.00 above film base + fog ( I can address those numbers later ). Like many in this thread I imagined the stain added about .20 in highlight density.

A gentleman from the Denver area brought me out to teach a workshop in 2015 on Pyro and Minimal Agitation. I asked if any of the students had densitometers they could bring, two of them brought X-Rites capable of reading stained negatives, much to my surprise I had a 1.02 neg measured on my densitometer which read over 1.5 on the X-Rites. I was quite surprised that stain added that much density to the highlights. That said, the stain will only impact a final process that requires Ultra Violet light, Pyro stain has no impact on the Silver Gelatin printer other than masking the grain structure which by most accounts is a Plus.

With regard to conventional wisdom of 1.25 highlight density for Normal grades of paper. I believe that is out dated thinking because of high quality Multi-Contrast papers and here's why.

Practical experience tells me when using only a Green or Blue light source to affect the softest contrast (Green) or hardest contrast (Blue) what happens is pure Blue affects Max contrast by building from the darkest tones first and the lightest tones last, thus creating Dmax long before any grey tone appears in the highlights. Conversely, using pure Green begins building highlight tonality first while not impacting the darker end of the grey scale very much at all except to diminish contrast greatly. Therefore, I use the phrase "contrast killing Green light". So that is why my negatives are designed to such a low highlight density above film base + fog. With highlight densities that low the final print requires much shorter soft contrast (Green) light and can then accept more hard contrast (Blue) light to create the final palette of grey tones. The big winner in what I call Contrast Formula is the mid tone micro contrast, the part of the print most difficult to control and also the part of the print the viewer reacts with most.

Cheers.

[Alan9940]

That said, the stain will only impact a final process that requires Ultra Violet light, Pyro stain has no impact on the Silver Gelatin printer other than masking the grain structure which by most accounts is a Plus.

Hello Steve,

Thank you so much for your detailed response. However, I'm a bit confused by this statement that stain color doesn't affect silver gelatin papers? I would agree that the stain has no or very little affect when printing on graded silver gelatin papers, but VC? I use an Aristo VC head which contains the V54 tube which, according to Aristo at the time this new tube hit the scene, was the preferred way to print on VC papers. Surely the stain color--yellow/green for PMK and others of this ilk and brown(ish) for Pyrocat-HD--will have some affect on the tone curve with VC papers depending on the color of the neg, won't it?



Practical experience tells me when using only a Green or Blue light source to affect the softest contrast (Green) or hardest contrast (Blue) what happens is pure Blue affects Max contrast by building from the darkest tones first and the lightest tones last, thus creating Dmax long before any grey tone appears in the highlights. Conversely, using pure Green begins building highlight tonality first while not impacting the darker end of the grey scale very much at all except to diminish contrast greatly. Therefore, I use the phrase "contrast killing Green light". So that is why my negatives are designed to such a low highlight density above film base + fog. With highlight densities that low the final print requires much shorter soft contrast (Green) light and can then accept more hard contrast (Blue) light to create the final palette of grey tones. The big winner in what I call Contrast Formula is the mid tone micro contrast, the part of the print most difficult to control and also the part of the print the viewer reacts with most.


This sounds like you're referring to split-grade printing?

I think what I'm going to do is start with a negative measuring 1.00 - 1.10 net highlight density, make some prints, and adjust from there. Practical experience with high values and my VC printing paper of choice should give me a pretty good idea of how much stain density is affecting the upper end of the curve. Once I have something acceptable, I can measure it and that value will become my norm.

Thanks, again.

[Jerry Bodine]

...I think what I'm going to do is start with a negative measuring 1.00 - 1.10 net highlight density, make some prints, and adjust from there. Practical experience with high values and my VC printing paper of choice should give me a pretty good idea of how much stain density is affecting the upper end of the curve. Once I have something acceptable, I can measure it and that value will become my norm...

Alan, FWIW coming from my total lack of experience with pyro developers, it seems to me that if you take two sheets of your chosen film and expose them in camera to a Stouffer wedge then develop one in a non-pyro and the other in Pyrocat-HD, you'd then be able to see the effects of the stain density over the entire zonal range. Granted, I'm out on a limb here.

[Steve Sherman]

Hello Steve,

Thank you so much for your detailed response. However, I'm a bit confused by this statement that stain color doesn't affect silver gelatin papers? I would agree that the stain has no or very little affect when printing on graded silver gelatin papers, but VC? I use an Aristo VC head which contains the V54 tube which, according to Aristo at the time this new tube hit the scene, was the preferred way to print on VC papers. Surely the stain color--yellow/green for PMK and others of this ilk and brown(ish) for Pyrocat-HD--will have some affect on the tone curve with VC papers depending on the color of the neg, won't it?

Hello Alan, you are correct in that the color of the stain does have an impact on the relationships that happen in the highlight region, that is the area most Pyro users site why Pyrocat's amber stain can create slightly more contrast within the highlights than the green stain of PMK. I neglected to explain that as I was making an assumption that so many non Pryo users believe that the stain adds density for all processes. The stain itself, color aside only adds density to a process requiring a UV light source, the color temperature of the light source used to print Silver Gelatin simply does not see the stain as density. Most photographers see the color difference of the stain between Pyrocat and PMK as the only difference between the two, I have worked extensively with both Pyros and do believe Pyrocat is a superior developer when taking into consideration the manner in which the mid tones are separated, too long to detail here nevertheless of value to this discussion.


This sounds like you're referring to split-grade printing?

I think what I'm going to do is start with a negative measuring 1.00 - 1.10 net highlight density, make some prints, and adjust from there. Practical experience with high values and my VC printing paper of choice should give me a pretty good idea of how much stain density is affecting the upper end of the curve. Once I have something acceptable, I can measure it and that value will become my norm.

Those neg. densities are a good place to start, however since I began printing with just a 0 and 5 filter I have continually designed my highlight densities to be under 1.00 for the simple reason the less 0 (green) light required to form highlights the better the mid tone contrast will be. Just the other day I printed a .83 highlight density neg. with great results, granted it was right about at the limits of necessary highlight density nevertheless a beautiful print.

Thanks, again.

[Alan9940]

Thanks, again, Steve you have been very helpful!

[Peter De Smidt]

Note that it's controversial whether split printing can give unique results if not applied locally, as per Phil Davis's article on it in Darkroom and Creative Camera Techniques.

[Doremus Scudder]

What Steve seems to be doing is simply designing his negatives to be printed at a higher-contrast setting than "middle," i.e., like using a #3 to #5 filter. This is a really good approach in my estimation; I find many VC papers have muddy mid-tones in the mid-to-low contrast range.

As for measuring effective density on a pyro neg: You need to measure at the same spectrum that your paper is sensitive to. IIRC, didn't Nicholas Lindan/Darkroom Automation have a densitometer designed specifically for dealing with pyro-developed negs? I don't know how active he or his company is anymore. Maybe someone does.

EDIT: The main page for Darkroom Automation is here: http://www.darkroomautomation.com/da-main.htm and it still shows the enlarging meter/densitometer for pyro negs.

Best,

Doremus