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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. #91
    Ian Grant's Avatar
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    Quote Originally Posted by Kirk Keyes View Post
    That seems to be a bit of a stretch... And then why not say that for any developer that has sulfite in it?
    They don't have that free SO3--

    Something's different in that early "Rodinal type" developer and it is very high dilution.

    Ian

  3. #92

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    Quote Originally Posted by Photo Engineer View Post
    This was my point as well but hidden in the chemistry.

    PE
    I'm glad we weren't just repeating each other!
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  4. #93

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    Quote Originally Posted by gainer View Post
    I'll see what I can do with step wedges. I'll have to relearn that as well.
    Don't worry about that, Pat - There's lots of people that would be more than happy to help you with this and give back to you some of ideas that you've given to us.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  5. #94

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    Man, I am so glad you guys are here to do all the difficult theorizing and critical testing. My feeble mind is crap these days. It seems that there are better alternatives to what I used a zillion years ago and I was VERY happy with good old Rodinal and selenium toning. I was convinced that I was going to avoid B&W and doing my own processing but, dad-blast-it, these options are very intriguing!!

  6. #95
    gainer's Avatar
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    Encephalitis can do strange things to a brain. It made my brain like a library without an index. The "books" were there, but I couldn't remember where I hid them. It could have been worse.
    Gadget Gainer

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    Hmm... maybe that's my problem... or just Alzheimer's plaque. Yeah, that's what I need. A good old fashioned brainwashing!!

  8. #97
    Photo Engineer's Avatar
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    Well, for those of you interested in mixing your own Rodinal, I would like to add some caveats on the NaOH or KOH solution used.

    Making a 50% NaOH solution involves 50 g of NaOH diluted to 100 ml for a wt / vol solution or 500 g diluted to 1000 ml for a larger quantity. You must start with ICE COLD distilled water, about 25 - 30 ml or 250 - 300 ml depending on volume. The slow addition of NaOH solid is so exothermic, it can crack some glass containers and can actually melt some plastic containers. You should have a large container of cold water to chill your mixing vessel.

    After you are done, there is much residual heat and you should cool the mix in a large mixing vessel. Make sure that no excess water gets into your diluted 50% solution.

    Leave the cap loose as it cools or the reduced pressure due to air cooling or volume reduction may crack the storage container. Glass can shatter, plastic can melt or crack. Do not store the final solution in glass, as NaOH can etch glass and can dissolve some inexpensive glasses. A spill will ruin most floors even concrete.

    Wear a lab coat with sleeves, old shoes, dirty clothes and protective glasses along with rubber gloves.

    That is how I just did it, and what I experienced and I am an old hand in the lab. Be careful, don't disfigure yourself or blind yourself from a tiny splash and don't ruin your darkroom from a spill.

    Have some automobile battery acid on-hand in case of a spill. I bought a gallon of 37% battery acid to have here just in case before I did this.

    Be happy, be safe, mix Rodinal by any formula with care. Mixing the NaOH or KOH is the first dangerous step. Adding this to the pAP and Bisulfite is no snap either. Take care when you do it. It is an acid base neutralization.

    PE

  9. #98

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    Quote Originally Posted by Photo Engineer View Post
    Have some automobile battery acid on-hand in case of a spill. I bought a gallon of 37% battery acid to have here just in case before I did this.
    While I agree with very nearly 100% of what PE says, I have to say that I disagree with the suggestion that 37% sulfuric acid be used in the case of a 50% or other concetrated acid spill. 37% sulfuric is still very acidic and I'd suggest using something weaker, like vinegar or dilute (i.e. 10% or less) hydrochloric or sulfuric acid.

    Using an acid this concentrated will invariable release even more heat and fumes and it will not make cleaning up easy. I've seen people in the lab I worked at use concentrated bases to neutralize concentrated acid and get burned much worse than the acid alone would have caused. It's the same principle at play here that should be avoided.

    To clean up a concentrated hydroxide spill, I would suggest the following:

    Solutions of sodium or potassium hydroxide greater than 10% have a contact rating of 4 - that means they are extreme hazards (i.e. they are corrosive). If you have contact during a spill, you should remove all contaminated clothing and then flush the contacted skin with large amounts of water.

    For cleaning up the mess, you should use the folowing protactive equipment - goggles or a face shield, an apron or some old clothes, and proper gloves. Make sure the area is well ventilated.

    You should contain and recover any spilled liquid when possible - wiping up with paper towels or spill pads will work well here. When the bulk of the spill has been contained, the residues from spills can be diluted with water and then neutralized with a diluted acid - dilute acetic, hydrochloric, or sulfuric will work here. Absorb neutralized caustic residue on clay, vermiculite or another inert substance and package in a suitable container for disposal.

    See this MSDS for 50% sodium hydroxide for more info: http://www.jtbaker.com/msds/englishhtml/s4037.htm

    I do completely agree with PE about being careful when preparing 50% hydroxide solutions. I would suggest only using Pyrex or other lab-type glassware as regular glass is just too likely to break if the solution gets too hot or too hot too fast.

    Do use very cold water, but I'd also suggest having a water bath of very cold water to set the container that you are mixing the solution in into. Add a few hydroxide pellets to the container and stir it continuously with the container sitting in a cold water bath. When thats dissolved, add a few more pellets and continue mixing. As the water bath begins to warm up, dump it out and refill the bath with cold water. This is another reasons to use a Pyrex-type container as it needs to be able to potentially hold a hot solution while sitting in a cold bath of water. Regular glass containers and plastic may not be able to handle these conditions. When the solution is mixed transfer it to a HDPE plastic container for long term storage.

    Another tip - do not simply dump all your hydroxide pellets into the container all at once. It will not only get very hot, but the pellets will simply sink to the bottom of the container and glue themselves together and make a big, hard brick of hydroxide that will be a very big pain the butt to get dissolved. (I have not done that personally, but I did see someone else to that... and I ended up cleaning that lump of hydroxide out of the container.)

    If you are going to mix large amounts, I'd suggest simply buying some. You can buy sodium hydroxide that's already at 50% concentration. After making up a gallon of 50% hydroxide one time, I've decided that I have better uses of my time and I don't like to take the risk that's involved in making large amounts of hydroxide solutions.
    Last edited by Kirk Keyes; 09-01-2009 at 11:04 PM. Click to view previous post history.
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

  10. #99
    fotch's Avatar
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    Well I won't be mixing it. Is the ready made stuff safe to use?
    Items for sale or trade at www.Camera35.com

  11. #100
    Ian Grant's Avatar
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    Health & Safety Issues

    Quote Originally Posted by fotch View Post
    Well I won't be mixing it. Is the ready made stuff safe to use?
    Fotch, commercial Rodinal is no worse than most other developers, and there's far worse chemicals used in most households on a regular basis.


    A couple of comments, I haven't advocated making up the old "Classic Rodinal" formula with it's higher level of Hydroxide, but we have discussed the formula.

    The amount of Potassium Hydroxide needed in the two formula I advocated in the opening post in Part 1 of this discussion is significantly smaller, at the highest 27g/litre. Potassium Hydroxide is harder to handle accurately as it comes in pellet or stick form unlike Sodium Hydroxide, but it is easy to buy as a 40% solution which is possibly the best option.


    Health & Safety


    Now Ron & Kirk have actually raised some more serious and fundamental issues about safety and handling chemicals used by many photographers, which are equally relevant elsewhere, and we need to remember that Lith devs etc are in far more common use and many use Hydroxide solutions. Equally many Toners & Bleaches use acids like Hydrochloric and Sulphuric.

    I'm fairly certain Kirk will have some kind of Safety guide where he works. In the UK chemical suppliers/manufacturers have to supply an MSDS/COSHH data sheet with each chemical the first time you buy it. (HSE - Control of substances hazardous to health (COSHH). Equally any company using any chemical must have the relevant data sheet.

    Using this data a Lab in the UK is required to draw up a COSHH Report on all the chemicals and processes it uses, which covers all aspects of safety, handling, what to do in the case of an accident etc, but with relevance to the volumes and way a chemical is going to be used. Copies of this usually hang on a wall in each relevant room in a lab so available for immediate use. (Ours were near to where the most dangerous chemical were used or stored).

    It sounds heavy, companies try and sell you software to do it, but in fact it's easy as nearly everything is in the MSDS sheets, and often handling & safety codes are in major chemical suppliers catalogues.

    What's missing is a free, easily printable, safety guide for photochemistry, no-one's going to buy a specific book, and while almost all manufactures from Ilford, Kodak etc through to the Photographers Formulary provide MSDS sheets it's not usuably in a practical form.

    Unfortunately I don't have access to a framework to drop the data into, it's archived in the UK, but perhaps if some has something between us we can put together informaton particularly for the most hazardous chemicals used in making up your own photo chemicals and emulsions.

    Ron's right about safety, and I know Kirk is aparticularly safety conscious from numerous posts he's made in the past.

    Ian



 

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