Dear Bill !!

Does your formular really works ?? Did you have made paper-prints in your lab or measured the whole think throught??
Just asking because I still work about another variation with is considerably more concentrated and will do it within the usual 3:15 minutes.

Coming from

Tab water 800 ml
Calgon 2.5g
Potassium carbonate (anhy) 37.5g
Sodium sulfite (anhy) 4.3g
Sodium bromide 1.4 g
Potassium iodide 1.2 mg (!)
Hydroxylaminsulfate 2.0 g
CD-4 4.5 g
Water to make 1.0 Litre
ph should be around 10.04 - 10.07

In small fraktions I increased the Iodide up to 2 mg / as well the CD4 up to 4.7g/L. I had solutions with different ph's from about 10.00 up to 10.15.

There is an approach with
Tab water 800 ml
Calgon 2.5g
Potassium carbonate (anhy) 37.5g
Sodium sulfite (anhy) 4.3g
Sodium bromide 1.4 g
Potassium iodide 1.6
Hydroxylaminsulfate 2.0 g
CD-4 4.5 g
Water to make 1.0 Litre
ph adjusted to 10.07 till 10.09 with sulphuric acid

The green layer(s) and the blue layer(s) match quite well, but the red is still a bit underrepresented. The densiotometric results are quite well, compared to a minilab processed grey pattern the results in D min, Dmax Speed and gradiation is virtually the same (deviation B-G 0.04 at the low densitys up to 0.09 in the high densitys). But R-G shows a observable deviation from -0.06 till -0.18 in the grey tablet. This is not OK and will lead to a slight color crossover in the print.
*these measurements are 'off standard' because I 1.dont have the real test strips and 2. because the R-G and B-G differences give me a better overview concerning color shift/spread. So no HD-LD curves here...


There are two suspects in my eyes,leading to my underrepresented red, thats is mainly a elevated ammount of sulfite (changes in ph did not brought the desired effect) and the bromide level. Sulfite acts as a preservative as well as a conditioner and reduces stain and Dmin. Dmin is actually good even when processing the films with extended time (3:25min) so here is a possible option.

Haven't tested this yet because of a lack of time...

On the other side, the bromide level is one of the very few known fixed points and should be abouit 1.3 g/L. Next runs will be with 3.2g / 3.4g Sulfite/ Litre, but i will do variate the bromide level in the range from 1.1 to 1.35g/L as well, if variations of the sulfite level will not have the desired effect to the red layer.
Increasing the Jodide up to higher levels (2mg/L) decreased the blue Dmax as well as the blue Dmin and is no option.

So the next formulation will be:
Tab water 800 ml
Calgon 2.5g
Potassium carbonate (anhy) 37.5g
Sodium sulfite (anhy) 3.2g
Sodium bromide 1.3 g
Potassium iodide 1.6 mg
Hydroxylaminsulfate 2.0 g
CD-4 4.8 g
Water to make 1.0 Litre
ph around 10.07

Keep you posted,
Regards from Germany,
Stefan