Digital BW, The Print

A few comments on "glop".

First of all I have had significantly better results using glop as a full
overcoat rather than "in the mix".  I do not share Carl's success with a 10%
flat application "in the mix".  I also tried a whole range of toner curves
with higher amounts of glop in the highlights etc (I believe Paul is using
this approach).  I also found that glop in the mix reduced dMax while an
overcoat of a fully dried print boosted dMax.

I am very suspect of the notion that glop works when it simply goes where no
other ink is.  In a quad system, even highlights have quite healthy levels
of ink application because of the use of light inks.  Yet severe bronzing
persists.  

In my experience an overcoat of glop at 50% (50% jet strength in QTR) is
required to remove bronzing.  45% doesn't cut it under halogen lighting for
example.  

QTR will apply a flat glop curve to the entire page unless the .quad file is
edited to place a 0 value in the first, paper white, value in the lookup
table. This is easily done but it is almost impossible for the printer (even
using the same driver) to perfectly align the same page twice.  Hence I coat
the page. There are no issues with overloading the paper as I let the print
dry overnight before coating it.

We battle two issues.  Bronzing which affects the highlights and reflectance
differentials which, in my view, affects predominantly the shadows -
especially pure black.  An overcoat addresses the latter much better.

I think we are all guessing as to what bronzing actually is - we know the
symptoms but what is it that we are actually seeing?  Why does it occur?
There is no bronzing on a blank sheet of paper and so the gaps of white
where there isn't any ink are not the issue.

The way I think of glop, at this stage, is that it is a protective coating
that somehow helps the bronzing and reflectance problem.  There are in my
opinion massive advantages to it being applied by a printer rather than as a
spray: precise application rate, very fine spray (1440dpi), no mess, no
fumes etc etc.  The current formulation of glop is not perfect.  In the
bottle it is urine in colour and does affect paper white to a certain
degree.  I would like to think though that in the advent of glop we have the
chance to find a good "coating substance" to enhance and protect prints via
printer application.

I suspect MIS created the current version of glop by, in essence, trying to
mimic the Epson product.  They are not happy with the current product (nor
their R800 inks) and should have a new version out very shortly.
Personally, I would like their chemist to think about the issues involved
(bronzing and reflectance) and the "advent" of printer application, and
think up a substance that does the job and can be applied by a printer -
regardless of whether it is glop or not.

Epson's design team are constrained by many factors.  The average guy who
buys a photo printer like the R800 (and it would seem they feel the same
about the R1800 as they are positioning it below the 2200) needs an
out-of-the-box one-pass solution.  They aren't going to do a two pass
process.  Bronzing is a lot less noticeable in colour images - I found a 15%
coating would hide the issue unless the colour image had substantial areas
of B&W.  Arguably we should not be so constrained.  We invest time in
exploring other inks, papers, calibration, coatings etc.

Steve


> From: koloshor <wiz@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Wed, 23 Feb 2005 03:18:36 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: [Digital BW] Re: glop concept goofy, temporary?
> 
> 
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Djon"
> <westsidemaurice@y...> wrote:
>> 
>> Why does a system need to apply glop in registration over specific
>> tones/colors/whites?
> 
> Because it only needs to be in places with no ink or little ink to even out
> the gloss differential.
>  
>> ...why not apply it over the entire rectangle, like spot gloss in
>> lithography?  
> 
> Because it woudl increase the glop utilization enormously, running printing
> costs way up.
> 
> And because it would increase the ink load (or at least the "wet load") on the
> paper, increasing rippling and warping, and increasing drying times.
>  
>> If that would work it'd be much more elegant (scientific elegance =
>> simple, reliable, effective).
> 
> It is more elegant, in every sense you have mentioned, to apply it only where
> it is needed.
> 
>> Why can't glop be put in a spray can...wouldn't it be better than the
>> various clear urethanes (which don't adequately deal with bronzing)?
> 
> They do, if you use enough. And that is because they have to completly
> overcome the gloss differential. Glop, applied only where needed, doesn't
> overcome anything, it just equalizes.
> 
> The spray varnishes protect the pritn from UV, gas, and abrasion.
>  
>> Glop, applied like a pigment or ink, sounds like a very temporary
>> solution, even assuming it proves to be workable (like "open loop
>> systems" and "profiles" and dye transfer and daguerrotype).
> 
> Are you trolling? Properly designed open loop systems are still used, because
> of speed and simplicity. Profiles are the only way to print accurate colors.
> 
> Ciao!
> 
> Joe
> 
> 
> 
> 
> 
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