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USE OF HC110 DEVELOPER

 Kodak HC-110 Developer     An Unofficial Resource Page     Sponsored by... See also my Kodak Xtol Developer Resource Page Deutsche Übersetzung dieser Seite Many thanks to Stefan Heymann for the translation! ... [Prosegue]

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KODAK D-76

Questa e39 una delle formule piu39 vecchie e piu39 utilizzate per lo sviluppo di negativi bianco e nero L39Ilford ID-11 differisce di poco rispetto al D-76 alcuni preferiscono l39ID-11 semplicemente perche e39 rimasto nel tempo piu39 simile alla formula originale mentre la Kodak per rendere compatibile lo sviluppo con tutte le acque del mondo (durezza) ha modificato piu39 volte la formula originale [Prosegue]

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FD-18

 FD 18 (Forte e non Agfa) acqua 750 ml metolo 6 g solifito di sodio anidro 100 g carbonato di potassio anidro 8 gr bromuro di potassio 1 gr  Da IAF (gruppo it.arti.fotografia) del 25-1-2003 Ho utilizzato in passato questa formula con PAN F Plus e FP4 Plus ottenendo un buon... [Prosegue]

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AGFA 120 (WARM TONE)

Said to give brown tones on Agfa Portriga (1:4) and warm black tones on Agfa Brovira (1:5) May be incorrectly named as the Ansco 120 formula above is often referred to in formularies as Agfa 120 [Prosegue]

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DUPONT FORMULA

I have never seen a developer with bicarbonate except as a buffering agent Metol will develop even in slightly acid conditions but very slowly It works fine at neutral pH as in Kodak D-25 If it worked as you envision it would produce high contrast images where in fact D-23 has good shadow detail and yeilds about the same speed as D-76 The difference is developing time for the same gamma D-23 takes longer Adding Borax will increase the activity and decrease the developing time An example is very old DuPont formula for motion picture negative film This was the result in DuPont180s research into D-76 type developers romide has an effect on film speed As developer is used it accumulates reaction products One of these is bromide Bromide tends to restrain the development of fog grains but at some point will also restrain the development of halide grains with little exposure For this reason used developer will have the effect of lowered film speed even when developement is carried out longer Metol is relatively less sensitive to bromide than Hydroquinone At the low pH of D-76 D-23 D-25 and the above developer metol does not produce much fogging so bromide is not necessary When a carbonate is used bromide becomes necessary because the higher pH causes more fog At the pH of D-76 Hydroquinone is nearly inactive as a developing agent Its function is regeneration of the Metol This results in somewhat greater capacity for D-76 than for the DuPont formula or D-23 However the slow reaction between Hydroquinone and sulfite produces a small amount of hydroxide which causes the pH to rise over a period of time Kodak180s cure for this was to buffer the developer by using a combination of Borax and Boric acid Current packaged D-76 is of this type DuPont found that the addition of Hydroquinone had no practical advantage and just left it out although later DuPont developers did include it It should be noted that highly active developers like Dektol (D-72) do not produce high film speed due to the necessity for considerable bromide The literature is filled with research on all sorts of developers and combinations Such publications as _The Journal of the Society of Motion Picture and Television Engineers_ and _Photographic Science and Engineering_ as well as extensive patent data will reveal all 1 quotBorax Developer Characteristicsquot H W Moyse and D R White (DuPont Redpath Labs) _Transactions of the Society of Motion Picture Engineers_ Vol XIII No 38 1929 p445 [Prosegue]

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