I was able to do some testing over the weekend using the Agfa 110 recipe. I could not get the potassium sulfite / Carbonate...... that will be for a future test. I tried two different papers using a 2x2 neg enlarged to 8x10.
The first paper I used was Agfa MCC-111 glossy. I exposed the print for 50.8 sec at f8 and toned for 30 min in Selenium for 30 min and obtained a Dark brown color shift.
The second paper I used was Bergger Warmtone Paper (cream based). This was the first time I had ever used this paper and learned quickly that my safe light was not so safe for this paper. This paper is also very slow. The same neg took 90 seconds exposure at f4 to produce the same results as the Agfa paper. When toned in selenium for 30 min, I was able to obtain the chocolate brown I was after, but the whites were not very creamy. More work to be done there.
I also noticed that the developer was very temperature sensitive, which sent me down the wrong path. I could not understand why the longer I was exposing the paper, why I was not getting better print. I measured the developer and the temperature had fallen to ~ 60F. After warming up the developer, things returned back to normal.
Tim Tim Eitniear Chicago, Il On Jan 26, 2007, at 2:34 PM, Tim Eitniear wrote:
Cor,To your point, I did some research on the chemical conversions I foundthe following two posts. In fact Lloyd's name was associated with the posts.I made the remark; it originally came from The Darkroom Cookbook, concerning potassium carbonate, and I extended it to sulfite. The latter is available from Photographer's Formulary at $16/lb. It doesn't specify the hydration status; the ratio of K2SO3 to Na2SO3 is 158/126, or about 1.25. I believe that the ratio of the carbonates is one of the hundreds or so errors still in the darkroom cookbook (the "corrected" edition); K2CO3/ Na2CO3.H2O is 138/124, so DIVIDE, not multiply, the amount of sodium carbonate by 0.9 tosubstitute the potassium version.I recently did a series of tests on Agfa MCC using warm and cold developers, substituting only the carbonate, not the sulfite; and potassium makes a final print that is noticeably warmer, especially after sepia toning. I plan to mix the developer with both potassium salts next time I use a warmdeveloper; I guess I or someone ought to compare potassium carbonate developers with each sulfite salt to see how big the difference is.Note that with cold papers, the differences resulting from these kind ofchanges is tiny, and often imperceptible.I don't know how difficult K2SO3 is to keep in dry form; the jar is still sitting on my shelf. I don't see why it would be any harder to keep thanthe sodium version, which is ubiquitous.You should be able to substitute potassium carbonate for sodium carbonatewithout concern, however, keep it tightly capped and dry, since it absorbs water from the air. The molecular weights are: potassium carbonate K2CO3 138.2 sodium carbonate Na2CO3 106 sodium carbonate monohydrate Na2CO3*H2O 124 If potassium carbonate is used rather than anhydrous sodium carbonate,the factor is 138.2/106 = 1.3X (1.30 g potassium carbonate used for eachgram of anhydrous sodium carbonate required).If potassium carbonate is used rather than sodium carbonate monohydrate,the factor is 138.2/124 = 1.11X (not 0.9X).If sodium carbonates are substituted for potassium carbonate, the factorsare the inverses of those given above (anhydrous, 0.77X; monohydrate, 0.9X). Both sodium and potassium carbonates give nearly the same pH, and thedifferences in development should not be evident if the correct amount issubstituted. Using much less carbonate than specified may warm image tone, but generally, developers don't affect tone very much compared to other factors (paper, toners, etc.).Benzotriazole might cool the image tone; usually, bromide (or developer reuse) lends a warm or greenish cast, but improves high value separation due to its restraining action. Both exposure (more) and developing time (longer) should be adjusted if significant amounts of restrainer are used. Adding more carbonate to a developer to which bromide has been added orhas accumulated, will cool the tone and decrease developing times, but retain high value separation. Using the factorial timing approach described by Adams is convenient to adjust times after additions (10% solutions of KBr and Na2CO3 are convenient). Tim On 1/25/07 4:06 AM, "C.Breukel@xxxxxxx" <C.Breukel@xxxxxxx> wrote:}January 24, 2007, from Lloyd Erlick, regarding Ansco 120 print developer: Thus: 12 g sodium sulfite anhydrous for one liter of *working*solution.The working solution I use contains 13.5 grams of potassium sulfite anhydrous. I've forgotten the arduous calculation that led to this,butthe solution works very nicely indeed. Maybe those more chemically adeptthanI am can correct my numbers .....ok I take the "challenge"..:-).. molecular weight sodium sulfite: 126,04 molecular weight potassium sulfite: 158,26So 12 g sodium sulfite equels (158,26/126,04)*12 = 1,26 * 12 = 15,12 gpotassium sulfite. A bit more than you use now, bit it ain't rocket scince, it probably won't matter too much.. Best, Cor===================================================================== =======================================To unsubscribe from this list, go towww.freelists.org and logon to your account (the same e-mail address andpassword you set-up when you subscribed,) and unsubscribe from there.====================================================================== ======================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.
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