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  1. #1
    Ian Grant's Avatar
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    Modern Rodinal Substitutes Part II

    Apologies for having to start a new thread but I can't read or even access the first to reply to posts.

    So with a bit of telepathy

    Quote Originally Posted by Kirk Keyes View Post
    Well, there's a problem there, as it's really hard to measure pH accurately when it gets much above 12.5 or so. You have to start getting special electrodes and the like.

    But for MSDS work, it doesn't have to be too precise.
    __________________
    Kirk

    A point that's being missed is that A&O give a figure of 2.7% Potassium Hydroxide not 3% in older Agfa MSDS.

    The pH is around 14 sure, but the actual requirement is the pH of the working dilute solution rather than the concentrate which is given elsewhere as pH 11.55, which I commented on in the first post of the thread.

    Way back Ron (PE) mentioned adjustments to Rodinal before bottling, the question we need to ask is are they adjusting on the basis of the concentrate, or also doing some tests on a dilute sample, as this will be a far more accurate indicator.

    Can someone please post a link to this continuation on the original post.

    Ian

  2. #191

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    Quote Originally Posted by Alan Johnson View Post
    Metol is said to be sensitive to hydrolysis in alkaline media:
    http://books.google.co.uk/books?q=me...G=Search+Books
    Now I read this book,the google quote gives the wrong impression.It is in fact phenidone which the book says is sensitive to hydrolysis in alkaline media.
    There is nothing about metol hydrolysis.

  3. #192
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    Alan;

    Something goes on with Metol in alkali. It turns dark right off even with lots of sulfite present, and it begins giving off a strong odor. This is the typical metol "breath of death". Since Metol is a stronger reductant (according to my references) than pAP, I do think something is going on.

    We also have the reports here of Metol based Rodinal work alikes losing strength rapidly.

    PE

  4. #193
    gainer's Avatar
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    I can't do much with Metol until I get some more. That batch that I put aside to age a while still needs to be tested again. Is it really necessary to have a single solution developer to produce the appearance of Rodinal? I think that we should broaden the search for means of preserving it beyond sulfite as I think I have with p-aminophenol in my previous posts. If I can make a 2-part developer having only p-aminophenol in the first part and only alkali in the second that has excellent speed, grain and resolution, even if it only lasts for an hour or so, It disproves some of my old beliefs about the role of sulfite, among others.
    Gadget Gainer

  5. #194

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    If 198g/L (1 molecular weight) sodium ascorbate is added to Metolal concentrate (M+A),the film speed is increased.For TMX EI: D-76=64,PC-TEA=80,M+A~160.The grain is reduced but could probably be restored to Rodinal like levels by making the concentrate more alkaline.Dev time M+A 1:50=2x that for Xtol 1+1.
    http://www.ccohs.ca/oshanswers/chemi...ium_hydroxide/
    Attached Thumbnails Attached Thumbnails TMY EI 400 M+A.jpg  
    Last edited by Alan Johnson; 09-13-2009 at 11:19 AM. Click to view previous post history.

  6. #195
    gainer's Avatar
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    Quote Originally Posted by Alan Johnson View Post
    If 198g/L (1 molecular weight) sodium ascorbate is added to Metolal concentrate (M+A),the film speed is increased.For TMX EI: D-76=64,PC-TEA=80,M+A~160.The grain is reduced but could probably be restored to Rodinal like levels by making the concentrate more alkaline.Dev time M+A=2x that for Xtol 1+1.
    http://www.ccohs.ca/oshanswers/chemi...ium_hydroxide/
    Now do it without sulfite, but with ascorbate.
    Gadget Gainer

  7. #196

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    Oh.Reviewing my notes,I did not put any sulfite in, so it was done without sulfite.
    Metolal derivative,call it MA-1:
    Water 150ml
    Metol 8g-if the solution is heated, be sure to cool to room temp before adding the next ingredient, the hydroxide.
    Sodium Hydroxide 15.6g
    Ascorbic acid 35.2g
    Water to 200ml
    For use dilute 1:50, develop for about 2x the Xtol 1+1 time.
    There are notes on sodium hydroxide safe use earlier in this thread.It attacks people and parts thereof.
    http://www.ccohs.ca/oshanswers/chemi...ium_hydroxide/

  8. #197
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    When we speak of grain, do we mean the size of the film grain or the appearance of granularity in the print from that negative? A resolution test chart is a help. It doesn't have to be an expensive one. A fairly coarse grid will show what we want to know. With lines and spaces of equal width in the original, photocopies may have wider lines than spaces in the negative due to infectuous development, or vice vesa due to certain edge effects. The whole business is complicated by scale effects from large to small formats. A perfectly sharp transition from black to white or light gray in the object will be seen by a subject to have a halo. An objective halo induced by development will be subjectively different in the same size prints from large and small format negatives. I think you all know these things, but I just want to make sure.
    Gadget Gainer

  9. #198
    Ian Grant's Avatar
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    Patrick raises a good point because Rodinal produces excellent fine grain with some films, so choice of film is equally as important.

    Ian

  10. #199
    gainer's Avatar
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    Quote Originally Posted by Alan Johnson View Post
    Oh.Reviewing my notes,I did not put any sulfite in, so it was done without sulfite.
    Metolal derivative,call it MA-1:
    Water 150ml
    Metol 8g-if the solution is heated, be sure to cool to room temp before adding the next ingredient, the hydroxide.
    Sodium Hydroxide 15.6g
    Ascorbic acid 35.2g
    Water to 200ml
    For use dilute 1:50, develop for about 2x the Xtol 1+1 time.
    There are notes on sodium hydroxide safe use earlier in this thread.It attacks people and parts thereof.
    http://www.ccohs.ca/oshanswers/chemi...ium_hydroxide/
    See www.unblinkingeye.com. Look for Vitamin C developers. There you will see some that are pretty close to what you have described above. Some of these developers are so easilly and quickly mixed that there is not much advantage to a concentrated stock, especially if you have a well-calibrated set of teaspoons.. Also, ascorbic acid and p-aminophenol base are soluble enough in glycol or glycerine to make a simple 2 part stock convenient, as I tested (crudely) in another post. If there is a definite need for sulfite, it can be added to the second part with the activator.
    Gadget Gainer

  11. #200

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    Vit C formulas may contain undissociated metol carbonate if there is such a thing,IDK.
    Ascorbate probably does not form undissociated compound with metol which would be present as its aminophenolate.



 

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