[alt-photo] Re: Ziatype questions

[Loris Medici]

Very interesting. COT320 normally doesn't absorb the sensitizer so easily (it's a pretty hard sized paper), and I experience no blotchiness... (You used the smooth / regular patterned side, right?) Is it possible that your stock sensitizer solutions (either the LiPd or the AFO) are somehow bad? Also, you mention *Tween*. I don't use it with COT320, I never had to use any surfactant for any of the alt-processes I did before - except for trad. cyanotype and some paper combinations. Have you tried w/o tween? (I just left using surfactants; when the paper is stubborn, I just extend the sensitizer with water...)

In any case, I would try to fix what's going wrong before venturing printing real images; to me it seems that you won't be able to use the full potential of the process with the current working parameters... (You really need to see 27-29 distinct and smooth steps - in the 31-step tablet test - to make sure your process works as intended...)

Regards and good luck!
Loris.


On 07.Ağu.2010, at 00:39, Vedos wrote:

> After another day of (test) printing I am pretty sure this is not a paper issue... made more tests on different papers. I also exposed one in sunlight, I had 16 minutes exposure instead of the uv unit's 4 minutes (but it was at 10 am, and the sun's power is much weaker here in Finland than, say, in Turkey ;)
> 
> Again, a short report of the day on the blog: vedos.samk.fi.