How would I test for this? (split grade printing, hype or real)

[Milpool]

I don’t think it’s worth getting into a whole argument over this but you’ve got your color theory 101 wrong, and it’s really about light more than color theory. I’ll yield at this point.

You clearly do not understand the significant difference, Milpool. Take any two true RGB color separation filters and put them together, viewing a strong light source, natural or artificial full-spectrum, and the result is almost black. I've even viewed solar eclipses that way. But take the strongest magenta and yellow filters you can find, do the same thing, and you'll see that a fair amount of residual white light still gets through.

Do the same thing looking a something bright red. With either a nearly pure green 61 filter of 47 or 47B blue, that red object will look black. But if you look at it with either a yellow or magenta filter, you'll still discern the red color. One catergory of filters is truly sharp-cutting; the other is not. No, VC papers are not sensitive to red light, but this does prove how some white light is getting through in
either case subtractively, whether Y or M, containing some of both blue and green as well as red.

Yes, you can go either way in terms of VC paper printing. Magenta subtracts green light, while yellow subtracts blue; but the effect can never be as downright intense as full true green versus full true blue. Color theory 101.

I don't want to press this fact too hard in the present context, because one rarely needs to go to those extremes with today's excellent VC papers unless they're dealing with really bad negatives to begin with, needing a lot of "salvage" printing. But there is a significant difference between additive and subtractive light in principle per se.

And there are times one basically just wants to print VC using ordinary enlarger light, but then add a little selective punch to one of the extremes exclusively. True additive G versus B filters do a better job of that.

 

[DREW WILEY]

Color theory is all about light. But like I already stated, one can take several potential routes when it comes to successful VC printing.
Just enjoy whichever particular method you prefer.

 

[Lachlan Young]

@pentaxuser it's the difference between what people think they should use in terms of grade/ exposure and what they should actually use.

 

[albada]

Thanks for that proof, The algebraic notation made my head spin a bit and I am not sure if I understood all of it so I need to ask some questions:

It's been decades since I created such a proof, so I had to go slowly.

What does d represent and likewise what is tb'? Clearly in your proof intensity of the green and blue are important as well green exposure, Am I correct in assuming that the effect of blue exposure on the print is the sum of tb+ib and likewise that of the effect of green exposure is tg + ig?

d is the time-difference between the two exposures. You are correct: Total exposure is tb+ib because they are logarithms (f-stops), and I should have pointed that out in the proof. In linear math, that equation would be Seconds * LinearIntensity, which is more understandable because it's obvious that doubling one variable doubles exposure.

If you've seen the video what I am about to say is redundant but if not then between mins 16-17 he states that his single grade print was grade 3 which he had produced in his previous video. So might half a grade to 3.5 made it the same as his split grade?

Yes. I think if John had gone back and adjusted time and grade some, he could have made his single grade print identical to the split-grade print. But here's a problem: filters come in steps of 1/2 grade, and if a split-grade print were near a 1/4 grade point, then no single grade print could exactly match it.

 

[pentaxuser]

@pentaxuser it's the difference between what people think they should use in terms of grade/ exposure and what they should actually use.

Thanks. A fascinating observation. If people use what they think they should then from what source does this thinking stem? Is there a convention of sorts which is leads them in the wrong direction that people stick to when printing which their inner selves tell them is wrong but they feel powerless to ignore? Where does this convention come from?

pentaxuser

 

[Lachlan Young]

As Ilford's own instructions for gen.1 Multigrade show, there's nothing new under the sun in terms of using a split-grade approach to define exposure & grade.

And it is extremely likely that Ilford, Dupont, Kodak, Agfa, and everyone else who made variable contrast papers will have thoroughly investigated whether there really were the claimed 'benefits' of split-grade, or if it was simply one tool among many for print contrast/ exposure determination.

 

[Lachlan Young]

What? Of course it does!

Paterson 'Acu' Range

Paterson, Chemicals

www.photomemorabilia.co.uk

There's not a single mention on there of FX-21 having development inhibition effects, and its formulae suggests that its chances of meaningfully delivering any are very slight, compared to developers that were meaningfully designed to do so (or that did so by initial accident of their design and subsequent emulsion research/ engineering - D-76 and modern emulsion designs will produce an intentional degree of inhibition effects - but not as strongly as some other formulae). There is good evidence that Ilford and Kodak (and likely everyone else too) had both tested & outflanked Crawley's various formulae and didn't find them worth pursuing. As a matter of fact, there is also a fair bit of solid evidence that shows Ilford (for example) was well aware that developers that did not act on the emulsion with a degree of solvency did not produce as good a balance of granularity and sharpness as those that did - i.e. a balance of physical and chemical, rather than purely chemical development (or 'surface development' in Crawley's words).

 

[Augustus Caesar]

There's not a single mention on there of FX-21 having development inhibition effects, and its formulae suggests that its chances of meaningfully delivering any are very slight, compared to developers that were meaningfully designed to do so (or that did so by initial accident of their design and subsequent emulsion research/ engineering - D-76 and modern emulsion designs will produce an intentional degree of inhibition effects - but not as strongly as some other formulae). There is good evidence that Ilford and Kodak (and likely everyone else too) had both tested & outflanked Crawley's various formulae and didn't find them worth pursuing. As a matter of fact, there is also a fair bit of solid evidence that shows Ilford (for example) was well aware that developers that did not act on the emulsion with a degree of solvency did not produce as good a balance of granularity and sharpness as those that did.

Wrongo! Crawley's formulas are for "perfectionists", as he himself told me when I wrote to him back in the 1980s. I have read about and experimented with many of his developers. They do not rely solely on "inhibition effects", but also on "chemical means". FX-14 (Acutol) was engineered to provide superior sharpness, and compensation mostly for the highlights, without adversely affecting mid-tone gradation. FX-21 (Acuspeciaal) was engineered to produce extra sharpness even beyond that produced by Acutol, but at the sacrifice of some mid-tone gradation, and was intended for slow, fine-grain films. I have found that FX-21 produces extraordinary results with T-Max 400, which behaves very much like slow-fine-grain films. You really need to learn more about this.


"
ACUTOL FX-14 DEVELOPER
Acutol gives maximum definition on films ISO 5-200 by increasing the apparent sharpness at the edges of fine detail.
It achieves this effect chemically, so allowing normal agitation and giving negatives of excellent gradation. There is only the slightest compression of the middle tones, more than compensated for by the brilliance of detail within the picture. The edge effect is most marked on high acutance films, which are generally 35mm films of speed rating ISO 5-200. As these slower films usually have quite high contrast, Acutol suits them very well and will produce impressive results on subjects containing textures.
Films faster than ISO 200 and most roll films do not give the extreme sharpness of which this developer is capable. Acutol is a medium fine grain developer and while it will give good results with fast films and roll films it is normally preferable to use Aculux and so ensure the finest grain and longest tonal range.
Acutol gives a ½stop speed increase, useful with the slower films and is well suited to pictorial photography.


Acuspecial FX-21 appeared by autumn 1969
A new type of soft working 'surface' developer invented by Geoffrey Crawley. "It is designed to give a special result with modern high performance slow and medium speed miniature films 5-200 ASA but may also be used with higher speed films. Acuspecial produces a negative of 'engraving' type sharpness and definition, coupled with extremely fine grain. The emphasis on this type of definition is obtained with a minimum reduction in continuous tonal gradation, and this is offset by exceptional separation of tones on fine detail. The disadvantages of streaking and inconsistency of action, usual to surface developers, have been overcome. There is an effective film speed increase of a half-stop.

Acuspecial does not replace Acutol which continues to give the optimum balance of tonal gradation, sharpness and definition. But the 'engraving' type negative given by the new developer, and the control of contrast which its soft working action provides, make it an important new tool for the knowledgeable photographer in the miniature and sub-miniature fields. Acuspecial is available as a highly concentrated liquid which is normally diluted 1:29 for use. Full instructions are supplied.

Paterson 'Acu' Range

Paterson, Chemicals

www.photomemorabilia.co.uk

 

[Keith Tapscott.]

Wrongo! Crawley's formulas are for "perfectionists", as he himself told me when I wrote to him back in the 1980s. I have read about and experimented with many of his developers. They do not rely solely on "inhibition effects", but also on "chemical means". FX-14 (Acutol) was engineered to provide superior sharpness, and compensation mostly for the highlights, without adversely affecting mid-tone gradation. FX-21 (Acuspeciaal) was engineered to produce extra sharpness even beyond that produced by Acutol, but at the sacrifice of some mid-tone gradation, and was intended for slow, fine-grain films. I have found that FX-21 produces extraordinary results with T-Max 400, which behaves very much like slow-fine-grain films. You really need to learn more about this.


"
ACUTOL FX-14 DEVELOPER
Acutol gives maximum definition on films ISO 5-200 by increasing the apparent sharpness at the edges of fine detail.
It achieves this effect chemically, so allowing normal agitation and giving negatives of excellent gradation. There is only the slightest compression of the middle tones, more than compensated for by the brilliance of detail within the picture. The edge effect is most marked on high acutance films, which are generally 35mm films of speed rating ISO 5-200. As these slower films usually have quite high contrast, Acutol suits them very well and will produce impressive results on subjects containing textures.
Films faster than ISO 200 and most roll films do not give the extreme sharpness of which this developer is capable. Acutol is a medium fine grain developer and while it will give good results with fast films and roll films it is normally preferable to use Aculux and so ensure the finest grain and longest tonal range.
Acutol gives a ½stop speed increase, useful with the slower films and is well suited to pictorial photography.


Acuspecial FX-21 appeared by autumn 1969
A new type of soft working 'surface' developer invented by Geoffrey Crawley. "It is designed to give a special result with modern high performance slow and medium speed miniature films 5-200 ASA but may also be used with higher speed films. Acuspecial produces a negative of 'engraving' type sharpness and definition, coupled with extremely fine grain. The emphasis on this type of definition is obtained with a minimum reduction in continuous tonal gradation, and this is offset by exceptional separation of tones on fine detail. The disadvantages of streaking and inconsistency of action, usual to surface developers, have been overcome. There is an effective film speed increase of a half-stop.

Acuspecial does not replace Acutol which continues to give the optimum balance of tonal gradation, sharpness and definition. But the 'engraving' type negative given by the new developer, and the control of contrast which its soft working action provides, make it an important new tool for the knowledgeable photographer in the miniature and sub-miniature fields. Acuspecial is available as a highly concentrated liquid which is normally diluted 1:29 for use. Full instructions are supplied.

Paterson 'Acu' Range

Paterson, Chemicals

www.photomemorabilia.co.uk

There is a photographer near to where I live who has photographed rural life in the county of Devon starting from around the mid 1970s to recently.

The photos are mostly taken on 35mm film using HP5 and it's replacement HP5 Plus all processed in Paterson Aculux. Olympus OM1 if I remember correctly.
I think he occasionally used a Pentax 6x7.

Most of the prints are on Ilford Galerie which are processed in Bromophen. 16x20 size paper.
The photos are excellent from what I have seen from his previous exhibitions.

Have a look at the link below and see what you think.

The Dartmoor Photographs of Chris Chapman

The Dartmoor photographs of Chris Chapman website

thedartmoorphotographs.com

 

[Craig]

If you have a densitometer, and know how to use it responsibly, split grade printing is essentially pointless. You have the correct tool to be able to define the optimal grade to start from & judge how you want to tackle areas you might want or need to dodge and burn at other grades. All of the various split-grade methodologies are workarounds for lack of a densitometer or trying to make enlargers essentially stepless in contrast grade. That's about all there is to it.

Could you elaborate on a procedure on how to do this? I have a dentistometer but I have no idea of how to use it to determine a paper grade I would need or an optimal exposure for making a print.

I also have an RH designs Zonemaster, is that something similar to what you are thinking of? It does suggest a paper grade after metering different parts of the negative when projected onto the baseboard.

 

[albada]

There's not a single mention on there of FX-21 having development inhibition effects, and its formulae suggests that its chances of meaningfully delivering any are very slight, compared to developers that were meaningfully designed to do so (or that did so by initial accident of their design and subsequent emulsion research/ engineering - D-76 and modern emulsion designs will produce an intentional degree of inhibition effects - but not as strongly as some other formulae). There is good evidence that Ilford and Kodak (and likely everyone else too) had both tested & outflanked Crawley's various formulae and didn't find them worth pursuing. As a matter of fact, there is also a fair bit of solid evidence that shows Ilford (for example) was well aware that developers that did not act on the emulsion with a degree of solvency did not produce as good a balance of granularity and sharpness as those that did - i.e. a balance of physical and chemical, rather than purely chemical development (or 'surface development' in Crawley's words).

@Lachlan Young , I have been suspicious of some of Crawley's formulas. For example, some employ two buffers though most developers have only one. Also, I have heard doubts expressed about some of Crawley's work from a couple of people. Could you post links or quotes? You mention "good evidence" and "a fair bit of solid evidence".

I have a densitometer, so an experiment I'd like to do someday is modify a Crawley two-buffer developer to use one stronger buffer, and determine whether image quality or curves became worse.

Mark

 

[Lachlan Young]

@Lachlan Young , I have been suspicious of some of Crawley's formulas. For example, some employ two buffers though most developers have only one. Also, I have heard doubts expressed about some of Crawley's work from a couple of people. Could you post links or quotes? You mention "good evidence" and "a fair bit of solid evidence".

I have a densitometer, so an experiment I'd like to do someday is modify a Crawley two-buffer developer to use one stronger buffer, and determine whether image quality or curves became worse.

Mark

Ian Grant has posted on here about his discussion of Crawley's developers with chemists from Ilford in the early 1980s - Ilford had apparently at one time been the contract manufacturer for the range - and the Ilford scientists' skepticism of the claims. The obvious subtext is that Ilford had gone through the range of formulae to check they hadn't missed something worth utilising themselves (all the major manufacturers had units whose job was to essentially dismantle the others products and see how they worked, then try to work round the patents - or to see who was infringing whose patent). Secondary to that however, is published material from Kodak researchers of the same time period where some of Crawley's formulae are pretty clearly outflanked - and there is microdensitometric data, which is really where key linkages to perceptual image quality come about. The third thing of note is that somewhere by the late 1990s Crawley's commercially manufactured developers all seem to get revised and some withdrawn (I would not be entirely surprised if his contacts in the industry had quietly persuaded him that some of the formulae weren't really doing what they were supposed to). At the end of the day, essentially all of Crawley's formulae will develop film competently, it's more the question of if they deliver optimal image structure/ image content transmission etc. There's also the problem that as the editor of the British Journal of Photography, Crawley had a level of cultural influence across the practices of a large swathe of photographers in the UK and wider afield, and there was what looks like a tendency amongst the readership - and those influenced by that readership - to trust his formulae more than that of the manufacturers - never mind the obvious conflicts of interest.

 

[Augustus Caesar]

@Lachlan Young , I have been suspicious of some of Crawley's formulas. For example, some employ two buffers though most developers have only one. Also, I have heard doubts expressed about some of Crawley's work from a couple of people. Could you post links or quotes? You mention "good evidence" and "a fair bit of solid evidence".

I have a densitometer, so an experiment I'd like to do someday is modify a Crawley two-buffer developer to use one stronger buffer, and determine whether image quality or curves became worse.

Mark

Why? Do you think you know more than he did? He revised and replaced several of them over the years.

 

[Augustus Caesar]

Ian Grant has posted on here about his discussion of Crawley's developers with chemists from Ilford in the early 1980s - Ilford had apparently at one time been the contract manufacturer for the range - and the Ilford scientists' skepticism of the claims. The obvious subtext is that Ilford had gone through the range of formulae to check they hadn't missed something worth utilising themselves (all the major manufacturers had units whose job was to essentially dismantle the others products and see how they worked, then try to work round the patents - or to see who was infringing whose patent). Secondary to that however, is published material from Kodak researchers of the same time period where some of Crawley's formulae are pretty clearly outflanked - and there is microdensitometric data, which is really where key linkages to perceptual image quality come about. The third thing of note is that somewhere between 1980-1990 Crawley's commercially manufactured developers all seem to get revised and some withdrawn (I would not be entirely surprised if his contacts in the industry had quietly persuaded him that some of the formulae weren't really doing what they were supposed to). At the end of the day, essentially all of Crawley's formulae will develop film competently, it's more the question of if they deliver optimal image structure/ image content transmission etc. There's also the problem that as the editor of the British Journal of Photography, Crawley had a level of cultural influence across the practices of a large swathe of photographers in the UK and wider afield, and there was what looks like a tendency amongst the readership - and those influenced by that readership - to trust his formulae more than that of the manufacturers - never mind the obvious conflicts of interest.

I have tried several of them, but Acutol remains the best I ever used. FX-21 (Acuspacial) works amazingly well with T-Max 400. Just try it!

 

[RalphLambrecht]

FWIW, I consider that latter example to be split-grade printing - more limited than applying the full technique, but still split-grade.

it is indeed and very effective.

 

[Keith Tapscott.]

The point I was trying to make in my previous post is that Aculux worked very well with HP5 Plus film and other films in the ISO 400 speed group.
I'm not saying it's any better than D76, just that it gives good results.

In the link I gave, the photographer used Galerie paper which doesn't help the OP who asked about split grade printing.

 

[Keith Tapscott.]

Ian Grant has posted on here about his discussion of Crawley's developers with chemists from Ilford in the early 1980s - Ilford had apparently at one time been the contract manufacturer for the range - and the Ilford scientists' skepticism of the claims.

I think Ilford felt that many of his formulas were over complicated rather than being skeptical of how they performed.
They reckoned that the same end results could be obtained with simpler formulations.

 

[Augustus Caesar]

I think Ilford felt that many of his formulas were over complicated rather than being skeptical of how they performed.
They reckoned that the same end results could be obtained with simpler formulations.

I understand that was their position. Perfectionists are interested in getting the last ounce of quality, no matter the cost. Crawley was close to that. The commercial Paterson developers were the best I have ever used. FP4 in Acutol was simply stunning! For what it's worth, I have been using Crawley's developers since 1969! I read his articles in the 1969 BJP Annual, and tried Acutol and Acuspecial. I don't remember if I tried KB14 in Acuspecial, but I did try it in Neofin Blue. I also tried Tri-X in Neofin Red. Didn't much care for that combination.

 

[Lachlan Young]

Could you elaborate on a procedure on how to do this? I have a dentistometer but I have no idea of how to use it to determine a paper grade I would need or an optimal exposure for making a print.

I also have an RH designs Zonemaster, is that something similar to what you are thinking of? It does suggest a paper grade after metering different parts of the negative when projected onto the baseboard.

I'm not sure how much more elaboration you need - I'd hope it should be obvious what you are supposed to measure and calculate from - and when not to base initial grade choices off a measurement on an overly dense highlight. As it is, I'll give you a hint: let's say the number you end up with is 0.7 - what grade of Ilford MG FB cooltone would be a likely starting point to use? I'm not advocating for eliminating a test strip, as it'll often clarify dodges & burns & local contrast adjustments, but if you really want, there are ways to calculate the exposure too - which is effectively what the Zonemaster is using its onboard paper exposure data to do & thus claim to eliminate test strips -the Zonemaster also doesn't require flare-factors to be considered. It's also worth noting that the Ilford MG600 probe can do the same grade/ exposure determination, and the MG500 probe can meter for exposure. None of this is new or earth shattering technology - if you go back and read up on things like the LogEtronics CRT enlargers, measuring negative contrast ranges is treated as a well understood and standard procedure in labs that had reasonably large scales of production.

At the end of the day, this is really simple stuff, it rapidly becomes very obvious whether you're measuring the right areas or not!

Either way, it's clear that this thread has been derailed by one of Ornello/ Michael Scarpitti's socks feeling a need to once again force us to listen to his obsessions with Geoffrey Crawley's developer formulae. It was old 20 years ago, and hasn't improved with time.

 

[Keith Tapscott.]

. The commercial Paterson developers were the best I have ever used. FP4 in Acutol was simply stunning!

I have seen some excellent prints from that combination when I started getting interested in photography and began seeing print exhibitions.

 

[Keith Tapscott.]

Either way, it's clear that this thread has been derailed by one of Ornello/ Michael Scarpitti's socks feeling a need to once again force us to listen to his obsessions with Geoffrey Crawley's developer formulae. It was old 20 years ago, and hasn't improved with time.

I use Ye Olde D76 and I don't think that has improved with time either, but it gives me negatives that I like.

 

[Lachlan Young]

I use Ye Olde D76 and I don't think that has improved with time either, but it gives me negatives that I like.

I think people don't realise how much research effort was expended by Kodak, Ilford and all the other big manufacturers in trying to equal or better the perceptual qualities that prints from D-76 processed negs had (have!) under double-blind test conditions. It also led to several really important research insights that many (especially those desperate for you to buy their patent medicine) are in denial about, but which all contribute to a perceptual end result that is very, very difficult to genuinely better.

 

[Keith Tapscott.]

Were the deleted posts done by the poster or moderators? Just wondering what was posted.

 

[Craig]

As it is, I'll give you a hint: let's say the number you end up with is 0.7 - what grade of Ilford MG FB cooltone would be a likely starting point to use?

That's what I don't know. So I measure a shadow and a highlight on the negative and get some values of density. Then what do I do with those numbers? I have no idea how that would translate to what filter out of the Multigrade set to use.

This is what I was hoping you might elaborate on, it's only obvious if you know what you're doing!

 

[Lachlan Young]

Then what do I do with those numbers? I have no idea how that would translate to what filter out of the Multigrade set to use.

Subtract the smaller number from the bigger, then multiply the answer by 100. Look up the ISO(R) number (sometimes 'Range (R)') on the relevant paper's datasheet and use the grade closest to the number you got.