Prescysol and the Zone System

Discussion in 'B&W: Film, Paper, Chemistry' started by marktweedie, Jan 21, 2006.

  1. marktweedie

    marktweedie Member

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    I've just decided to give Peter Hogan's chemicals a go and wondered if anyone had any experiences of using these with Zone System concepts. It seems from what I have read that altering development times to change contrast will not have the same result as with a non-staining developer. In fact, it seems that as long as the exposure is vaguely OK that you can develop however you want and that the Zone System is effectively redundant! Surely too good to be true! I aim to report back when I have tested but would welcome any experiences of others so far.
     
  2. Dave Miller

    Dave Miller Member

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    That's my experiance; I look forward to reading about yours.
     
  3. Stoo Batchelor

    Stoo Batchelor Member

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  4. Dave Miller

    Dave Miller Member

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    Lets clarify a this a little bit for those unfamiliar with this developer.

    Since the recommended development time for any film in Prescysol EF is either 8 min with agitation or 10 1/2 min partial stand then it follows that increasing or decreasing development times to modify contrast is probably a waste of time. Peter Hogan suggests experimenting with the strength of the brew to achieve contrast changes, but I haven’t tried.
    I particularly like the way I can mix film makes, and speeds in the same development cycle, for example Maco IR820, Delta 100, and Delta 400 in the same tank.
    The staining effect has the effect of reducing negative contrast, making them much easier to print.
     
  5. df cardwell

    df cardwell Subscriber

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    The Zone System is, after all, a SYSTEM.

    Which incorporates several elements, from deciding what the picture-on-the-wall is to look like; to which lens, filter, and film will be used, how it is to be exposed, developed, printed, and illuminated on the wall.

    Conventionally it is practised by envisioning the image of the subject you wish to make, measuring how it departs from reality, exposing and developing the film to result in an ideal negative from which you can easily make the print you wish. There are limits, of course, to what can be achieved.

    Alternatively the same results can be accomplished by developing the negative to satisfy specific qualities which allow the variability to be achieved in printing.

    The chief merit of a 'standardised and ideal negative' is that local contrast is not sacrificed to the conventional interpretation of 'zone system', which mandates specific end points on the curve whilst allowing the more important midpoints to fluctuate.

    A staining, compensating developer ( be it PMK, PyroCat, or Prescysol EF ) brings many properties which are effectively exploited by a ' standardised and ideal negative '. For the majority of subjects we tend to photograph, and the majority of situations we tend to make pictures, it is easy to satisfy Zone System criteria by:

    1. visualisation
    2. exposure for the deepest shadow as it will need to be in the print
    3. 'Standard' development
    4. Printing, using normal or soft developers in conjunction with variable grade papers to achieve the visualised image.

    This will make perfect sense to some, and be anathema to others.

    Here is an example of an image made under this system, illustrating its practicality: full and velvety shadows; normal local contrast and density of midtones, and rich variation of highlights that are neither 'blocked' nor 'blown'. Exposure: 1/30 at f/1.4; Film: TMY @ 400; Developed normally in Aculux 2. Printed on #2 paper, in selectol soft & dektol. Subject brightness 8000 : 1.

    Any film/developer combination with a long straight-line ( HP5, FP4, for example ) would have made the same image. Prescysol EF would likely have allowed more control in the printing, and reduced the need for 2 bath development.
     
  6. Stoo Batchelor

    Stoo Batchelor Member

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    Spot on Dave

    And like you, I havn't needed to experiment as I get perfectly developed Negs everytime. Which is why I use it.

    Actually, it would be nice to know if you have tried two reels of 120 in the same tank, but not on the same reel. Barry Thornton recommended not to practice this with Di-Xactol, I can understand the reasoning behind it, but I can't remember reading anything about Prescysol.

    Kind Regards

    Stoo
     
  7. Leon

    Leon Member

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    My developer of choice is Pyrcocat HD - but having used both this and Peter's Precyscol, I can say they are very similar with almost identical results - I only use the PC because I mix it myself and this works out way cheaper than buying Precyscol.

    NOw both developers work on the x amount of part a, to y amount of part b to z of water. If I want give my film an n+ development time, I increase the amount of part b - with pyrocat and fp4 that means 1:1:100 for 14 mins at partial stand give me my n time. 1:2:100 for 14 mins partial stand gives me my n + development. the excellent effects of catechol on highlights means you dont really need to worry about n- times.
     
  8. Dave Miller

    Dave Miller Member

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    I’m not clear as to your meaning Stoo. I normally but two 120 films on each reel as this is the most economical method. I have used up to five reels in a tank i.e. 10 films at any one time, which I find a bit nerve racking. Generally the films will be of mixed types, and all rated at the manufactures standard times; the exception being Maco 820 which I had to trial to establish its rating with this developer. That speed worked out to ISO ¾ whereas in Rodinal I rated it at ISO4.

    Leon raises the question of cost, but since so little Prescysol is needed, and the shelf life is so good I don’t consider this a factor considering all the other costs involved just to get a developed film into the tank. Maybe some one would like to do the sums, and post a price comparison.

    If I were using sheet film, then the zone system would be attractive, but since I use roll film, and a roll may contain a range of shots, and lighting conditions, I don't find it too helpful in practice. However it can be a useful tool to employ when needed, but that's another subject for another day.
     
  9. pentaxuser

    pentaxuser Subscriber

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    Dave and others. From what I have read it would seem that in low light situations the film could at least be rated at twice its box speed and still produce useable negs.

    Is twice box speed the limit? If not can more be risked by altering ratios of developer and to what detrimental effect on those negs shot at box speed.

    I have often been in situations the ideal combo would have been with HP5+ where at least EI 800 and sometimes EI 1600 would have been helpful. Classic case is the need for outdoor shots, then indoor shots such as church interiors, museums then nightime available light shots all on the same roll. Often on the same day!

    From all accounts XP2 gives some of this flexibility but is better at lower than box speed rather than higher and cannot really be used at more than twice box speed.

    Pentaxuser
     
  10. Stoo Batchelor

    Stoo Batchelor Member

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    You have answered my question perfectly Dave.

    Previous to using Prescysol, I was a user of Di Xactol. Barry Thornton would say that by using more than one reel in a tank, with the partial stand method, you would, he believed, produce uneven development. He painted a picture in my mind of the film sitting in the developer, and while the film stood un-agitated, the developer would very slowly seperate, so the developer at the bottom of the tank would be slightly stronger than at the top, causing un-even development. Barry's standing time was a recommended two minutes. Peters is three, bar the period after your last agitation, which is slightly longer. With this in mind, and the thought of the developer seperating, I thought the longer standing period would magnify the un-even development problem.

    I have been developing all of my films individually up to now. Not confident of putting two films on one reel (from a days shoot, three would probably be the norm anyway) I have been toying with the idea of getting a larger developing tank and developing three films together, one per reel.

    The good news is that your already doing this, all be it with two films per reel, with out any development problems. Fantastic, I'm going to save a fortune let alone valuable time.

    Now if you told me that you have successfully developed Delta 3200 @ 6400 in Prescysol, that really would be a dream come true!

    Thanks for your help

    Kind regards

    Stoo
     
  11. Leon

    Leon Member

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    Dave - I mix p-cat to 100ml of each solution to be used at 1:1:100. If I remember rightly, PH's Precyscol is supplied as 100ml bottle of a, and 500 ml of b to be used at 1:5:100 so it would give the same capacity as the p-cat. 100ml of P-cat A and B costs me £1.05 -

    Precyscol (or EF version) is £15.99 with shipping. for the same capacity ...

    Assuming I'm putting 2 rolls of 120 film onto one reel giving roughly 33 films worth of developer, pyrocat = 3 pence per film, Precyscol = 49 pence per film

    As I said earlier, in my unscientific testings, pyrocat HD and precyscol give pretty much the same results.
     
  12. craigclu

    craigclu Subscriber

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    I realize I'm sounding dense here but I had tried Prescysol (and liking it) when Peter first was promoting it and some time later had my first PyroCat experiences. This thread had me looking back at my Prescysol negatives and I realize now that the two are very similar in behaviors. I had abandoned Prescysol at the time, simply because of trouble shipping liquids in the dead of winter in my northern climate and recurring problems in this regard. The EF variant sounds very interesting and I would be interested to hear of others' results with it.
     
  13. Dave Miller

    Dave Miller Member

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    Although it’s valid for you to do so, I’m not sure that it is fair to compare a home brewed product with a commercial preparation in the context of this discussion. To make the argument relevant, I think your calculations should be based on the commercial form of your favoured developer. Prescysol EF dilutes to make sufficient for 40 rolls of 120, assuming no waste. This translates into 10 lt of developer, compare this to the price of, say CM Pyro that costs £11.50 for 5 lt and the numbers start to drop into place. Having said that when the total cost of a developed film is analysed, then the developer cost, whether 3p, or 40p is insignificant. Then again I suppose it would get me another half cup of coffee during a shooting break.

    I cannot say if Prescysol is the best developer available, all I can say is that it is the best that I have found; and I’m happy enough with the results not to be in any hurry to find another.

    Craig, I’m not sure why you think you are sounding dense when making a worthwhile contribution to the thread. Given the exceptional shelf life of these products, could you not consider stocking up during the summer.
     
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  15. craigclu

    craigclu Subscriber

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    I'm accustomed to working around that but the timing happened to work in such a way that I went off in other directions, both from weather timing and the fact that I was having an interesting time getting back into homebrew projects. I'll step to the head of the line in promoting that people give Prescysol a try as I have little doubt that it would readily become a good tool to have on the shelf and likely a "go-to" reliable performer that can be trusted to deliver. I'm so deep into a dizzying array of homebrew concoctions and variations of others' formulas that I am busily getting stabilized again! I do very controlled experimenting in my daily career work and I'm afraid I've let my variables get carelessly/loosely away from me at home in the retreat of my darkroom. I have everything somewhat tuned and have learned very much but I'm struggling to get shadow detail and still hold onto the good things that I've got going for me. I'll likely end up retreating to my stand-by developers (likely including Prescysol), PyroCat types and DS-10 which has become my favorite for Delta series films.
     
  16. sanking

    sanking Member

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    Dave,

    I am not sure why you find the comparison unfair. The Pyrocat-HD formula is available and you are free to mix it yourself, or buy the commerciallly prepared formula from various sources. Presysol is a proprietary formula so you are tied to the cost of the commercial product.

    Based on everything that has been said it seems likely that Presysol is very similar to Pyrocat-HD, and probably derived from it. It may, in fact, be the same formula, except for the substition of the Stock B 75% potassium carbonate solution with a 15%-20% sodium carbonate solution, which is of course an alternative method of mixing Pyrocat-HD which I have previously recommended. I obviously don't know exactly what is in Presysol, but when two formulas give results that are almost identical, I think it is reasonable to assume that they are highly similar, if not identical, in composition.

    BTW, I would be willing to trade someone an equal amount of Pyrocat-HD for Presysol in order to do sensitometry comparison tests of the two developers.

    Sandy


     
    Last edited by a moderator: Jan 21, 2006
  17. Dave Miller

    Dave Miller Member

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    Sandy,
    I explained why I thought it unfair, I was trying to compare like with like. In this case two commercial products, since there are others, who, like me, use too little film developer to make it variable to consider mixing our own. Those that do would naturally follow Leon’s costing.
     
  18. sanking

    sanking Member

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    Jay,

    I have not yet found a source for the thin glass on the Wejex. Have been out of the country for a while so this has been put on hold. If I find a replacement I will send you the information. If you come up with it first, please do the same.

    Agreed, removing the glass was one bitch of a job.

    Sandy


     
  19. Leon

    Leon Member

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    sorry Dave - I thought that was what you were asking for when you mentioned a price comparison .... I wasnt trying to "sell" you the whole home-brew ethos, no offence meant :smile:

    The difference between 3 and 50 pence may be only a cheap cup of coffee, but the difference between £1 and £16 is a night down the pub for me so that's 4 extra beer sessions a year by my film usage - not to be sniffed at :smile: - or several slices of that cheesecake you and Frank talk about.

    I stopped using Presyscol because the B solution kept solidifying and I had to heat it for long periods to disolve it all each time I used it. My darkroom gets quite cold when not in use in the winter and I think that is what caused it.
     
  20. marktweedie

    marktweedie Member

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    Leon, you have nearly won me over to the idea of homebrew! When my batch of Prescysol is finished I will give it a go. I have looked at Silverprint for chemical prices but didn't manage to get to the 3p a shot figure. Where do you buy your raw materials?
     
  21. Dave Miller

    Dave Miller Member

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    Check out
    Retrophotographic
    as well.
     
  22. marktweedie

    marktweedie Member

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    Thanks Dave, their prices seem identical within a couple of pence but I have discovered a fault in my maths and have now come up with a per sheet cost of 3.5p homebrewed vs 32p using Prescycol. For me using 225ml of solution in a vertical homemade BTZS tube per sheet means that a saving of £7 per box 25 sheets of 5x4 film is possible. This can make a real contribution to the cost of new lenses, paper, tripods, lighting gear, beer... the list goes on...

    I think I'm with Leon on this one with the one proviso that I can accurately reproduce my formulation with each new mix.

    I also notice on ebay,seller olympiceyewear has jewellers/medical weighing scales of various types available from the US for about half the cost of buying in the UK (inc P&P) . Can anyone vouch for their accuracy?
     
  23. Dave Miller

    Dave Miller Member

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    If you use a Paterson Orbital processer then you will only need to use 60ml per 4 sheets of film.
     
  24. marktweedie

    marktweedie Member

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    How does that work with partial stand? Surely this would need continuous agiatation?
     
  25. Dave Miller

    Dave Miller Member

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    That's correct. I only use partial stand because I'm lazy. I have a motorbase for the orbital processor. :D
     
  26. Blighty

    Blighty Subscriber

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    I've seen Pete Hogans Prescysol developers and was quite interested in them. I've only ever used Barry Thornton's Dixactol and Exactol Lux developers. How do the Prescysol devs compare to these? My experience of Dixactol showed it to be very forgiving in terms of exposure (errors?) with very high acutance and useful edge effects. This was (IMO) at the expense of grain, which at 35mm was quite obtrusive, obviously less so in 120 format. One 'problem' I found with Dixactol was it produced a very long tonal scale and I needed to print hard to get a reasonable amount of 'snap' into my photo. This produced an unwelcome increase in apparent grain in the print. Anyway, to get back to my original point; how do they compare?