Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,203   Posts: 1,531,651   Online: 1158
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1

    Join Date
    Sep 2002
    Posts
    368

    Clarification aboutPyro

    We have slightly revised the piece on pyo's health hazards on our web sites

    wwwiewcamera.com
    www.cameraarts.com

    the first paragraph was actually a question Mr. Knoppow was rsponding to

    I am still waiting for the critics of this piece to bring newl ight to the topic rather than just be critical.

    On anther note in the current issue of CameraArts I have compared PM and HD with 35mm FP4+ In the Juy issue of View Camera (out in about 10 days) I compare PMK and HD with Tri-X and FP4+ 4x5 sheet films.


    steve simmons

  2. #2

    Join Date
    Dec 2002
    Shooter
    Large Format
    Posts
    6,242
    Quote Originally Posted by steve simmons
    We have slightly revised the piece on pyo's health hazards on our web sites

    wwwiewcamera.com
    www.cameraarts.com

    the first paragraph was actually a question Mr. Knoppow was rsponding to

    I am still waiting for the critics of this piece to bring newl ight to the topic rather than just be critical.

    On anther note in the current issue of CameraArts I have compared PM and HD with 35mm FP4+ In the Juy issue of View Camera (out in about 10 days) I compare PMK and HD with Tri-X and FP4+ 4x5 sheet films.


    steve simmons
    Steve, Thank you for your continued service to the photographic community. I am particularly interested in the articles that you mentioned and will await them with anticipation. Were you able to verify your comparisons by densitometric comparisons, or were these more in line with visual observations?

    On a separate note, I have reread the posts pertaining to the other notice that you posted. I do not find where anyone was in disagreement with Mr Knoppow. They were only expressing the evident and that was that Mr. Knoppow had indicated an opinion that was not backed up with any verifiable independent scientific study by others. That is the only contention that I find in those posts. That does not put his opinion as a provable disclaimer to the things that Howard Bond has written and also the other posts on the internet by others as you had mentioned.

    I wish that there were verifiable evidence contrary to Mr. Bonds position. Perhaps the closest to that was the information that Annie provided via a link to a study on Pyrogallol. As I have previously mentioned I use Pyro and I like the benefits of Pyro. I don't believe all of the scare tactics used...but then it seems to me that most of the world wants to be afraid.

    In summary, Steve, I don't think that I observed one person on this site at odds with Mr. Knoppows statements or your beliefs. I ask that you reexamine your position in this regard. No one was attacking anyone. The only question raised was that of an opinion expressed and seemingly represented as proof positive.

  3. #3

    Join Date
    Mar 2003
    Posts
    270
    As an addendum to Mr. Knoppow's article, Jorge & Kirk provide some very valuable information as to the interpretation of some of the available data and handling methods for pyro in the darkroom here......
    http://largeformatphotography.info/l...ic/498792.html

  4. #4
    scootermm's Avatar
    Join Date
    Jun 2004
    Location
    Austin, TX
    Shooter
    ULarge Format
    Posts
    1,867
    Images
    235
    all the debating about pyro etc seems a little odd. But Im interested in purchasing some pyro and comparing FP4 4x5 sheet film with it and other developers. just interested in seeing first hand what all the recent coverage is about.

    always interested in new processes.

    thanks for the links steve.
    and also..... thanks for the book. its what got me to purchase my first 4x5.

  5. #5
    garryl's Avatar
    Join Date
    Jul 2003
    Location
    Fort Worth, TX
    Shooter
    35mm
    Posts
    542
    Images
    2
    Quote Originally Posted by steve simmons
    On anther note in the current issue of CameraArts I have compared PM and HD with 35mm FP4+
    steve simmons
    2 questions~~
    Why FP4+ as the test film?
    What bookstores handles this magazine?
    __________
    "Just because nobody complains doesn't mean all parachutes are perfect."

  6. #6
    lee
    lee is offline
    lee's Avatar
    Join Date
    Nov 2002
    Location
    Fort Worth TX
    Shooter
    8x10 Format
    Posts
    2,913
    Images
    8
    I am gonna try this again. I get mine at Borders at I 30 and Hulen by the Central Market and I also get them from Barnes and Noble near the Ballpark in Arlington at Collins and I 30. Sometimes they sell out before I get to buy one.

    As to why FP4, I cannot say other than to agree that it is a nice film that responds favorably to PMK and Pyrocat-HD and seems to be a favorite for many largeformat shooters. I actually prefer HP5+ for the extra stop or two of film speed.

    lee\c

  7. #7
    garryl's Avatar
    Join Date
    Jul 2003
    Location
    Fort Worth, TX
    Shooter
    35mm
    Posts
    542
    Images
    2
    Quote Originally Posted by lee
    I get mine at Borders at I 30 and Hulen by the Central Market
    .... I actually prefer HP5+ for the extra stop or two of film speed.
    lee\c
    Thanks Lee, I'll try there.
    I've been thinking of trying FP4+, but how does HP5+ react in PMK/ Pycat-HD?
    "Just because nobody complains doesn't mean all parachutes are perfect."

  8. #8
    lee
    lee is offline
    lee's Avatar
    Join Date
    Nov 2002
    Location
    Fort Worth TX
    Shooter
    8x10 Format
    Posts
    2,913
    Images
    8
    Garryl,
    HP5+ is really green in PMK as is Tri-X (old film cannot say on the newer emulsions) and is, in my way of thinking, much easier to get a full box speed out of the film. I think that is because of the overall general stain. FP4 is likely to not have as much green stain as HP5+. It seems to me to be more brown and limited to the actual image. Many like this and I would too but I really don't have too much experience with FP4 but have seen a butt load of them processed in PMK and they do look different, I think.

    With Pyrocat-HD there won't be as much visible stain and that is seen by some as a benefit because it makes the exposure take less time. I don't have too much experience with Pyrocat-HD as I am just starting my relationship with Pyrocat-HD. Donald Miller is an expert on Pyrocat-HD and Efke films from JandC Photography. He is big into largeformat film and semi-stand development in tubes, like the ones BTZS sells. Very sharp clean negatives.

    HP5+ is a low contast film in my opinion. It may not be the best choice for expansion development as it may not create enough density. It is not the only film out there with that issue.


    lee\c

  9. #9
    c6h6o3's Avatar
    Join Date
    Oct 2002
    Shooter
    Large Format
    Posts
    3,172
    Images
    6
    These citations from NLM's TOXNET of authoritative, peer reviewed toxicological and pharmacological studies involving pyrogallol may serve to help provide some of the clarification mentioned in this thread's title.

    National Library of Medicine - TOXNET Search on 'Pyrogallol'

  10. #10
    Aggie's Avatar
    Join Date
    Jan 2003
    Location
    So. Utah
    Shooter
    Multi Format
    Posts
    4,925
    Images
    6
    I read all that was on toxnet. I went so far as to see what studies had been conducted to base the assumptions on. One is that the tests were only done on animals (rats, mice, and rabbits) from these you have to read the protocols that were used on those tests. For the ones where death was attributed, they took massive doses of pure pyrogallol and injected it direct into the blood stream of rabbits. First anything in that proportion they injected would cause serious damage. Second no one is going to main line the equivalent of those doses direct into themselves.

    As for the skin irritations they used guinea pigs. they shave a large portion of their body, salved on a highly concentrated amount, wrapped it in plastic then tin foil and kept it on there for 24 hours, then repeated for another 24 hours. The skin showed irritation (DUH) and they had eyrthmea (irregular heat beat) which the heart beat cleared up by 72 hours from the start once they took the wrappings off and left it exposed to the air. The skin thickened once exposed to air, and became dry. all of it flaked off and was back to normal in 8 to 10 days depending on the animal. Now how many of you are going to salve it on in high concentrations and wear saran wrap style dressings and leave it there for 48 hours?

    NO TEST HAS BEEN DONE ON A HUMAN. that was one thing noted. All the evidence that is cited and reviewed has been of anecdotal cases. No mention of the full case history of those cited. Could there be other mitigating factors for some of those cases? Yes this is a gov. agency that has compiled this, but as you can tell there has not been any hard substantial evidence done in clear cut manner to cause even the FDA to ban, limit, or label it as a major hazard. It does need to be handled with care. I am not saying it shouldn't. Wear gloves. It will stain your skin. It can cause dermatitis or other reactive skin problems to those sensitive to chemicals. DO WEAR a mask when working with the dry form. DO not serve yourself a meal made of mostly the pure form. DO NOT drink a highly concentrated cocktail of it. BE responsible and do not Drink it and drive.

    Remember above all the small amounts you will be working with. Remember the time or duration of real contact with it. And Remember that once mixed, it oxidizes rapidly. Most often it is entirely inert (not toxic) within 10 to 15 minutes.

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin