Digital BW, The Print

wwodets wrote:

> Thanks for all the responses.  I have been using the random target, 
> 51 patches, strip read, the occasional glass of wine (but not two) 
> and a white card overlaid with a piece of the same paper.
> 
> I have not been averaging multiple targets or reads, though I've done 
> consecutive profiles and overlaid then and find them extremely 
> close.  I imagine that this would have to be done by manually 
> calculating the averages for each of the 51 steps and then entering 
> them in the Measure Tool text file.  Is that correct, or is there 
> something sleeker I'm not thinking of?

My youngest son wrote a small command line averaging program 
for the PC but for color targets. It might be usable for the 
51 steps target but I have to check that. Printing two or 
three different targets on a wide format roll at the same time 
with one of them 180 degrees turned  is a sensible thing to do 
as the printer is used that way and by that the drying time 
between strokes etc corresponds more to daily practice.  I 
sometimes observe a small difference in color at the start of 
a printjob, having the patches reversed on one target reduces 
the problem + printing another file just before it helps too. 
Cleaning the heads to get all the nozzles is good too but you 
should at least run a normal print before printing the target 
to get the head in its normal printing condition.

BTW, Epson has a hidden advice in the Colorbase FAQ that says 
no speed printing (bidirectional) is color consistent due to 
the reversed order of laying down of the hues and the 
increased dotgain.  So even for their x800 printers they give 
that advice. I have never before seen that advice but always 
suspected that something happens in the reversed laying down 
order.. Can't recall right now what the subject line was in 
the FAQ that covers it but ithe same subject line appears 
twice in the FAQ with different underlying texts.


> A sample of three is probably better than a sample of one, but 
> *statistically* a sample of three (compared to thousands of prints 
> done with the profile) is probably meaningless (small "N"). 

When offset presses are  profiled the profile people select a 
quantity of say 12 target prints of a print run. Based on 
their knowledge at what time the variations in the printrun 
occur. The quantity of sheets produced on an offset press with 
the same profile must be a 100x more though than what is done 
with one profile on an inkjet printer. I'm trying to reduce 
reading errors and print variation at the same time. I have to 
say that the profiles I made since adopting that method are 
more consistent than the ones before.

                    --
           Ernst Dinkla


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