Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., "Martin Wesley" 
<mwesley250@e...> wrote:
> Mike, Nij, Lawrence, All,
> 
> After following all of this for over a year it is very clear that 
there is a
> vast difference in the experience with Piezo inks. Some people have 
had the
> experience of it starting right up and never having a problem. 
Others have
> experienced multiply and chronic problems from the start. Others 
have fallen
> somewhere in between.
> 
> I think that these experiences are all real and we need to take this 
into
> account. I do not know why the experience varies so much. I tend to 
doubt
> that it is ink batch related as the people who have no problems have 
gone
> through different batches over a period of time.
> 
> Perhaps the Piezo inks are less tolerant of printer-to-printer 
variations. 

No that is not what I would test for first. I would track the obvious 
variable.

Time. Or rather how much ink is used over time. If you want to take a 
survey, simply ask three questions:
1) inkset used
2) positive or negative rating (say 0 to 10). Nij is quite right about 
 a neutral scale; one must be able to both praise or condemn or the 
data will be meaningless.
3) How much ink is used per month say. Or word it like this: how many 
days a month is your printer used? Or, how many hours per day? Or you 
can phrase it thus: How many 8x 10 equivilents / month? The best would 
be to get BOTH a mean value of ink usage/ printer on time /month AND a 
standard deviation of that usage.

Standard deviation is a measure of variability of the data, if you 
don't know. For example if I turn my printer on every day and print 
exactly one 8 x 10 only, and do a repeat exactly the same every day 
for a month, my S.D. is nil. If however, I print out forty 8x10 one 
day, three the next day, and then none for three weeks, I will have a 
high S.D.

I propose an hypothesis that with Piezo ink, and probably with others 
to some extent, low means and high S.D. will correlate with more 
negative ratings. This condition is indictive of inks sitting around 
unused for awhile, and seeing sporadic usage. I would venture that 
folks printing every day mass quantities of piezo prints would have 
less problems. Therefore with sporadic use, the ink is inclined to 
break down, clog the printhead more, perhaps sludge up a CIS, and 
other things we have all come to know and love.<g>

In the past, I limited myself to honing a positive definition of DSS 
(density shift syndrome) only. It is not my place I felt to pass 
judgement on how the problem should be tested, resolved, or even to 
pass judgement on any inkset. Since I gather from this thread that no 
answer has been forthcoming, I now merely suggest an hypothesis and an 
approach that might prove interesting.
Jim H.



> > Maybe I am missing something but it appears that the problems 
associated
> with the Piezography ink set is becoming epidemic in magnitude. I 
think that
> IJM still claims there are only 20 or 30 people that are very vocal 
and
> having problems. Perhaps Martin can start a poll in the files 
section asking
> for comments about problematic Piezo inks and negative experiences. 
That way
> we can begin to see the magnitude of what is occurring.