Message
Re: [QuadtoneRIP] Re: Ink limit low limit
2015-01-28 by sanking@...
Did you make prints with both negatives or compared the smoothness by viewing the negatives?
A print sometimes reveals artefacts that are hard to detect in the negative.
Ultimately the print is the only comparison that matters, and I of course have made that comparison, with a variety of methodologies. And absolute smoothness is to some extent dependent on picoliter size. For example, with the same methodology, profile, etc. a digital negative from a 1.5 picoliter size printer makes a smoother print than a digital negative made with a 3.5 picoliter size printer. The difference is not great, and may only matter with smooth papers and certain subjects.
Using as many channels as possible to get the density you need is maybe the most important factor to get smoothness, rather than the amount of ink balanced with its dilution.
The key in my opinion is balance of the UV inks. But the amount of ink needed, at any given dilution of ink, is dependent on the log density range requirements of the process.
I don't know if different printers's ink limits can be compared, but it seems you use much greater density!
I'm making multiple transfers prints which could explain it, at least partially.
My negatives, with the K8-12 profile give a log density range of about 2.15. The Carbon 100 profile, which uses PK, Y and LK (balanced to give equal UV blocking), gives about the same DR. This is about optimum for single transfer carbon, and would be about right also for pt/pd. If we are going to compare this we need to speak the same language, i. e. log transmission range of our negatives, and exposure scale of our process. That is to say, basic sensitometry. I could of course adjust my carbon process for a negative of lower density range, but there are down sides to doing this.
As for the droplets, there must be so many of them overlapping that their sizes are probably not of importance. Especially when using an all-grey ink set, with no darker dots.
Yes, I think that is one of the keys to smoothness.
But I remember your comment about graininess with different printers and droplet sizes and still wish I had a better understanding of "variable size droplet technology", and control on it.
Smaller picoliter drops do give more smoothness. But I have no idea how to control this with QTR and the Epson print head, or in fact even if it can be controlled.
Sandy