What is your experience with Pan F 50 Plus?

[Lachlan Young]

I’m actually looking at modifying my setup a little bit to try to extract a bit more light out of it so I can get to at least zone 10, though I’d really like to expose up 7-8 stops over middle gray just to see what’s going on up there with replenished xtol. The slower films really tax my setup, but I think I need to make a couple modifications as I’ve got a handful of 80, and 25 speed films to work out development times for and right now I just don’t have enough light to make full 10+ zone exposures.

Wouldn't you be better off building a sensitometer setup using a (calibrated) step wedge?

 

[Adrian Bacon]

Wouldn't you be better off building a sensitometer setup using a (calibrated) step wedge?

the landlord to the place I’m renting won’t allow me to make the modifications to make my darkroom light tight enough for film. For bw paper, it’s fine, but I can’t get it dark enough to avoid exposing the film while getting it in/out of a sensitometer. Besides, this is replenished xtol, I’d prefer to run film through it in roll size quantities so the replenishment is simple and easy.

 

[DREW WILEY]

Plotting can be done more easily with a pre-manufactured step tablet and contact exposure onto sheet film of the emulsion in question, and then densitometer reading the result. But that requires a true darkroom. Any stray light whatsoever ruins the accuracy of toe plotting, and acts like flashing above that. With films with high ASA sensitivity, or even slower films with a steep toe, even the luminous hands on an old fashioned darkroom timer on the other side of the room will skew the results and give you something misleading. To objectively plot and compare b&w films on the market today, you need accuracy, in ZS terms, all the way from 0 to around 12. That means plotting all the way from the fbf of the step tablet all 21 steps, which are .15 density (or half a stop) apart. That might take you beyond printable density, but does show you if and when the shoulder begins, along with other key aspects of the entire curve, and how different development regimens affect them. Don't laugh, 12 "zones" of light is not that rare in the high mtns, desert, or even out here in the redwoods when the sun is out. If Ansel Adams was Moses, he didn't quite get the job done with only 8 commandments or Zones. Pan F obeys only five of them. ... You could probably rig up a little black flocking removable booth between the enlarger lens mount and the baseboard, with sleeve opening cannibalized from a film tent, and do contact frame step tablets tests within that.

 

[Adrian Bacon]

Plotting can be done more easily with a pre-manufactured step tablet and contact exposure onto sheet film of the emulsion in question, and then densitometer reading the result. But that requires a true darkroom. Any stray light whatsoever ruins the accuracy of toe plotting, and acts like flashing above that. With films with high ASA sensitivity, or even slower films with a steep toe, even the luminous hands on an old fashioned darkroom timer on the other side of the room will skew the results and give you something misleading. To objectively plot and compare b&w films on the market today, you need accuracy, in ZS terms, all the way from 0 to around 12. That means plotting all the way from the fbf of the step tablet all 21 steps, which are .15 density (or half a stop) apart. That might take you beyond printable density, but does show you if and when the shoulder begins, along with other key aspects of the entire curve, and how different development regimens affect them. Don't laugh, 12 "zones" of light is not that rare in the high mtns, desert, or even out here in the redwoods when the sun is out. If Ansel Adams was Moses, he didn't quite get the job done with only 8 commandments or Zones. Pan F obeys only five of them. ... You could probably rig up a little black flocking removable booth between the enlarger lens mount and the baseboard, with sleeve opening cannibalized from a film tent, and do contact frame step tablets tests within that.

making a tent around my big enlarger did occur to me, and I haven’t taken it off the table just yet. I did do some re-work on my current setup and was able to eek out f/22 at EI 80, which would put zone 6 at f/16 which would at least get me to zone 10 at f/4 which my lens opens up to. Technically, it opens up to f/2.8, but in transmission stops, it’s T3.1, so I stop at the T4 mark on the lens.

 

[DREW WILEY]

It's just so much easier using a pre-calibrated step tablet. To do it correctly using aperture changes, you'd need to actually test those settings using an easel densitometer - any expensive rare toy. I have one. The other problem with changing apertures is that you're changing the incidence of the light going from small to large apertures. That might not be a major issue if the lens is back off far enough and it's a relatively long lens relative to film size, but it might be an issue up close, which appears to be the case if you're trying to eek the most light out. But to whatever degree of accuracy you might want to take this project, a dark tent would be an asset. Just be careful with the material and keeping it a safe distance from anything hot like a colorhead. Or you could make a mini-darkroom just around the enlarger area using PVC pipe stands and buying a roll of high-quality black photographic velvet (not the paper-backed kind).
Not ideal in terms of lint issues; but I did my first exhibition based on a makeshift arrangement like that, and processed the sheet film in the furnace closet - not an ideal spot either!

 

[Adrian Bacon]

It's just so much easier using a pre-calibrated step tablet. To do it correctly using aperture changes, you'd need to actually test those settings using an easel densitometer - any expensive rare toy. I have one. The other problem with changing apertures is that you're changing the incidence of the light going from small to large apertures. That might not be a major issue if the lens is back off far enough and it's a relatively long lens relative to film size, but it might be an issue up close, which appears to be the case if you're trying to eek the most light out. But to whatever degree of accuracy you might want to take this project, a dark tent would be an asset. Just be careful with the material and keeping it a safe distance from anything hot like a colorhead. Or you could make a mini-darkroom just around the enlarger area using PVC pipe stands and buying a roll of high-quality black photographic velvet (not the paper-backed kind).
Not ideal in terms of lint issues; but I did my first exhibition based on a makeshift arrangement like that, and processed the sheet film in the furnace closet - not an ideal spot either!

I’m using a 100mm transmission rated lens mounted to a 35mm camera and just filling the frame with an 18% grey card that is roughly the size of an 8x10 print. I’ve checked the grey card and it does reflect close enough to 18% that I’m well within my margin of error for being able to measure it. The lens has been measured and has the physical iris control on the barrel of the lens along with marks for each transmission step in full stop increments. I set the lens to infinity focus. The light measurements are taken with a sekonic incident meter at the plane of the grey card that I’ve also checked for accuracy and it is indeed accurate and measures in 1/10 stop increments. For faster films I have plenty of light to very evenly illuminate the grey card, its just the slower speed films that I have trouble getting the upper zones of light.

I’m not necessarily looking to reproduce ISO or manufacturing tolerances, but, with my current setup, am pretty confident that I’m easily within 1/10 of an fstop in terms of amount of light actually hitting the film in the camera, which for uses of determining development times and graphing an H+D curve is probably overkill, but I’d rather make it as accurate as I can within reason with what I have access to than just say my tolerance is +- a third of a stop. For somebody who’s just trying to work out a personal EI for stuff they shoot and develop themselves, a third of a stop is good enough to get them in the ballpark. Since I run film for other people, I want to know with a fairly high level of confidence that a given emulsion really needs x amount of time if shot at EI whatever.

 

[Lachlan Young]

Because I got bored, I quickly scaled both of Ilford's curves to match the plot Adrian has published and then shifted (very quickly and very roughly - I am not desperately inclined to spend hours cleaning off all of the artefacts of Ilford's graphs) the graph to line up with the b+f line. Pale grey is ID-11, darker is HC.

Discuss as you wish. The ID-11 curve checks out to G-Bar 0.62 pretty accurately I recall. Remember that in dealing with Ilford films, average gradient is what they design to, so these specific curve behaviours are likely there with good reason. Generally, if you get a result that significantly disagrees with the manufacturing data, you're more likely than the manufacturer to be making an error in your system of measurement or what you think the 'correct' density of a particular step should be.

 

[Adrian Bacon]

Because I got bored, I quickly scaled both of Ilford's curves to match the plot Adrian has published and then shifted (very quickly and very roughly - I am not desperately inclined to spend hours cleaning off all of the artefacts of Ilford's graphs) the graph to line up with the b+f line. Pale grey is ID-11, darker is HC.

Discuss as you wish. The ID-11 curve checks out to G-Bar 0.62 pretty accurately I recall. Remember that in dealing with Ilford films, average gradient is what they design to, so these specific curve behaviours are likely there with good reason. Generally, if you get a result that significantly disagrees with the manufacturing data, you're more likely than the manufacturer to be making an error in your system of measurement

well, there you go.... the darker HC one looks to have the same shape as I’ve published. I’ll bet if you stuck them on top of each other there’d be shockingly close if not dead on.

 

[Lachlan Young]

well, there you go.... the darker HC one looks to have the same shape as I’ve published. I’ll bet if you stuck them on top of each other there’d be shockingly close if not dead on.

Give or take the approx stop of speed loss, yes.There's still the question over why ID-11 produces such a significantly different curve above 1.0 density, but it may simply be down to specific developer exhaustion.

 

[Adrian Bacon]

Give or take the speed loss, yes.

Ilford’s is relative log exposure. It doesn’t indicate what they actually exposed it at. I exposed mine at EI 50 and processed it to as close to G-bar 0.62 as I could reasonably get it.

 

[Adrian Bacon]

Give or take the approx stop of speed loss, yes.There's still the question over why ID-11 produces such a significantly different curve above 1.0 density, but it may simply be down to specific developer exhaustion.

also, looking a little closer, should the horizontal line on Ilford’s chart be at 1.0 instead of 0.9?

 

[Lachlan Young]

Ilford’s is relative log exposure. It doesn’t indicate what they actually exposed it at. I exposed mine at EI 50 and processed it to as close to G-bar 0.62 as I could reasonably get it.

The time they state for the curve from HC is the same as they state for an EI of 50, but the speed rating test is carried out in ID-11. On that basis, how they match up to your results, and that HC-110 type developers are cited by Kodak as delivering a slower shadow speed than D-76, and that there's perhaps 1/3 stop difference between D-76 and Xtol in shadow speed, I'd suggest a stop slower shadow speed in HC compared to Xtol is probably a reasonable starting point for testing.

also, looking a little closer, should the horizontal line on Ilford’s chart be at 1.0 instead of 0.9?

I think they go from absolute 0.0 rather than b+f. I shifted their curve up so that both your & their b+f's lined up - which was about 0.1 I think.

 

[Adrian Bacon]

The time they state for the curve from HC is the same as they state for an EI of 50, but the speed rating test is carried out in ID-11. On that basis, how they match up to your results, and that HC-110 type developers are cited by Kodak as delivering a slower shadow speed than D-76, and that there's perhaps 1/3 stop difference between D-76 and Xtol in shadow speed, I'd suggest a stop slower shadow speed in HC compared to Xtol is probably a reasonable starting point for testing.



I think they go from absolute 0.0 rather than b+f. I shifted their curve up so that both your & their b+f's lined up - which was about 0.1 I think.

fair enough

 

[DREW WILEY]

"Average gradient" might be OK for general marketing purposes; but I find it misleading when it comes to predicting behavior at the low and high ends of the curve, which are especially important in real world use. For that reason, I can't think of a single Ilford film I use box speed for, unless the scene contrast level is moderate. In every case I have to use a lower ASA, often half the rated box speed, in almost any developer I can think of. But HC-110 is a bit of a chameleon, depending on the degree of dilution, so I don't accept generic statements about it either. It all depends. And here again, if density is not plotted logarithmic, it's clumsy to make any kind of apples to apples comparison.

 

[mmerig]

mmerig - you're totally wrong. Look at the length of the published curves in relation to each other. Practical testing confirms exactly what I stated, and it's been a known problem with PanF for decades. Even Ilford's marketing literature and description of these two respective films implies exactly the same thing. I've made hundreds of densitometer plots with FP4 (both old and new style), have shot and printed a great deal of it, especially 4x5 and 8x10 sheets, and have every legitimate reason to believe I understand these films far better than you do. I've got the two published curves right in front of me, right now, in their official tech sheets. You've stated all this backwards. It's Pan F that has the limitations of an S-curve, and FP4 the long straight line once it launches off the toe.

In retrospect, I should have mentioned the publications I was referring to, and they are Ilford's data sheets for Pan-F Plus from June 2010 and FP4 Plus from April 2004. The respective graphs (attached here) use the same domain, range, and units, and the same developer. I think a reasonable interpretation for Ilford's comparison is that the FP4 curve is more S-shaped than Pan-F's, and Pan-F has a longer toe than FP4, as I mentioned in my previous post.

Other posters have mentioned or demonstrated that different developers etc. can influence the shape of the curve. You claim to have done many tests. Why not show some of them to us?

Sometimes, my work takes me away from civilization for days or weeks, thus my tardy response.

 

[pentaxuser]

Well I can certainly see an S shape in FP4+ whereas there appears to be no such shoulder on Pan F. I think Drew is saying that either Ilford has accidentally swopped the curves or is saying that Ilford's plotting is just too crude to show the Pan F shoulder?

At least we now have two Ilford curves that use the same developer and seem to cover the same range.

Perhaps Drew can indulge me just once more and just clarify what mistake Ilford has made

pentaxuser

 

[Andre Noble]

I did not have luck with PanF 50

 

[Tom Kershaw]

I did not have luck with PanF 50

Dilute developers are a good option for Pan F Plus. Suggest Rodinal 1+49, or Tetenal Ultrafin 1+24/29.

 

[Andre Noble]

Thanks

 

[DREW WILEY]

Just go shoot some of each of these two respective films in a high contrast situation and then try to print texture in both the lowest and highest values. Then maybe you'll understand just how significantly different the characteristic curves truly are, even if unfamiliar with how these curves get plotted. An S curve implies very little tonal separation in the deep values and highlights, and that is the INHERENT CHARACTERISTIC of Pan F. But the inherent characteristic curve of FP4 is a moderately short toe and then a long straight line thereafter, which is why it is capable of good tonal separation all the way from shadow to fairly bright areas, several more stops overall than Pan F.

 

[pentaxuser]

Just go shoot some of each of these two respective films in a high contrast situation and then try to print texture in both the lowest and highest values. Then maybe you'll understand just how significantly different the characteristic curves truly are, even if unfamiliar with how these curves get plotted.

Thanks Drew. This reply pretty much replicates your previous reply. What I was hoping you'd do is to show either what is wrong with the Ilford curves or show where on the curve the Pan F shoulder arrives. Has Ilford not shown enough in its graph for users to see that in a high contrast situation Pan F has limitations that FP4+ does not?

Can you show us your two curves so we may see what the variation with the Ilford curves are. I am unclear whether your curves are the same or very similar to Ilford's for the portion Ilford shows and then the top part of the S appears or whether your curves are different throughout from the Ilford curves?

Thanks

pentaxuser













eves neves raealr mialr hter your curves tePresumably your curves eves u the |Ildfoy

 

[DREW WILEY]

I'm not set up to post visual content right now. But let me add an analogy. Photographers often prefer somewhat long lenses for facial portraiture to avoid distortion. But millions of other people stick a cell phone camera with a BB lens right up to a face, and it turns out looking bloated with a big nose. Potentially the same person, but dissimilar portraits. The same thing happens if a long densitometer plot is scrunched to fit a small graph, versus a short line stretched to fit the same space. It's not an apples to apples comparison.

 

[Lachlan Young]

Both Adrian's and Ilford's data is plotted on log scales, they just needed scaled to match. What is clear is that with the multi-emulsion construction of modern films, it's possible for a developer to run out of steam on different emulsions at different rates, producing curve behaviours which may or may not be useful - as opposed to the ancient N-/N+ orthodoxies founded in the era of single emulsion k-grain films.

Average Gradient is arguably the least bad of the three methods of measurement (as opposed to CI and Gamma) in terms of accounting for the overall impact of the non straight bits of the curve, however I'd suggest that it's not just shadow/ highlight curve behaviour that's important to understand, but the fundamental impact that significantly raising or lowering the midtone gradient through attempts to soften or harden highlights and shadows will have on printability and overall tone. All too often I see boasts of extreme N- development on something like HP5+, usually followed up by whining that the subsequent negative is hard to print (often compounded by a stop or more of underexposure)...

 

[DREW WILEY]

The whole point I was making is that Pan F BEHAVES like an S-curve film, while FP4 behaves as having a moderate toe followed by a long straight section. These respective characteristics can be tweaked somewhat, but not really be fundamentally switched. ...HP5 has a substantially longer toe than FP4, but not an S-curve. It eventually shoulders off. I used it quite a bit in 8x10 format, but didn't like it any smaller format. PMK dev gave it esp high edge acutance, yet delicate non-gritty "watercolor grain". It did a fine job in "normal"but not extreme contrast scenes (too much toe for that). I'd deliberately over-develop it to expand midtone and upper microtanality, and then add an unsharp contrast mask to tame the overall contrast. That way the full crisp tonal range would come out in a hard grade print, whereas a traditional Zone System minus dev or compensating approach, or lower grade paper, would have forfeited that special quality.

 

[Lachlan Young]

while FP4 behaves as having a moderate toe followed by a long straight section. These respective characteristics can be tweaked somewhat, but not really be fundamentally switched. ...HP5 has a substantially longer toe than FP4, but not an S-curve. It eventually shoulders off.

There's nothing controversial or unusual about that, at least in ID-11/ D-76 from my experience - and the older Ilford tech sheets from the 90's seem to generally say the same. I've never had any need/ desire to test them in Ilfotech HC.