Digital BW, The Print

Hi Joost,

>>A call to the other EU guys: what if we would jointly try to order from
the US a larger batch of the exact same surfactants as Paul has used and
divide them amongst ourselves? Maybe a UK location is most logical but also
I would be happy to act as a distribution center myself. Any interest?

I'd be interested, though I probably just need some more Edwal LFN. These
are available in cheap ($7) little 20ml bottles that are easy to post. I
would be happy to act as a EU distribution / payment collection point if we
could find someone in the US willing to post a few of these to me. The
retailers all want big $$ to ship, which then means you end up paying duty
(as they add shipping to cost) and a $7 bottle becomes $100 of cost !!

I am making 5% Photoflo 600 work just fine. You'll see an HP-C6 based print
from me in the UK exchange and another couple in Feb / March in US exchange.
Mike

2010/1/27 horstenj <j.h.j.h@...>

>
>
> Thanks again Paul,
>
> Your post reveals so much better all the work you have put in this. It
> makes me to even more admire your expertise and endurance....
>
> Frankly, it also makes a bit (to translate a Dutch saying) "my courage to
> sink into my shoes" to redo all this work for different ingredients........
>
> A call to the other EU guys: what if we would jointly try to order from the
> US a larger batch of the exact same surfactants as Paul has used and divide
> them amongst ourselves? Maybe a UK location is most logical but also I would
> be happy to act as a distribution center myself. Any interest?
>
> Joost
>
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com<DigitalBlackandWhiteThePrint%40yahoogroups.com>,
> "pr_roark" <roark.paul@...> wrote:
> >
> > "horstenj" <j.h.j.h@> wrote:
> >
> > > ... To pre-empt subsequent questions as it turns out that we in Europe
> have difficulties to get exactly the same chemicals as you have used:
> > >
> > > 1) Tergitol: what is its purpose?
> >
> > It's one of the surfactants. This is is from Dow and appears to be highly
> thought of. It incrementally improved, particularly, the Arches performance
> when added to the C6b mix (Photo Flo and LFN). The removal of either one of
> the previous surfactants decreased smoothness.
> >
> > My observation is that one of the variables that is very important is the
> nature and mix of surfactants or wetting agents that are used. They affect
> droplet formation, paper penetration, bleed, cleaning -- a fair number of
> performance parameters. In general, we want non-inonic surfactants that are
> compatible with the other ingredients. It takes a mix of different types.
> They'll line up on the water-X surface differently depending on what that X
> surface is -- air, paper, metal. They tend to be types of alcohols (as is
> glycol) that are water soluble.
> >
> > Photo Flo has Kodak's proprietary version of this type of alcohol in it.
> >
> > Edwal LFN has 3 different alcohols in it.
> >
> > > If we can't get the exact same version, what is essential to pay
> attention to?
> >
> > Go to http://www.dow.com/surfactants/products/second.htm and click on
> the Tergitol 15-S-7 link, as well as a few others. A number of the specs on
> that sheet are important, and I cannot recall all the specifics. (I read,
> learn, try the most likely few, find a solution that works and move on,
> largely erasing the blackboard.) At one point I understood the cloud point,
> HLB, pour point, CMC and some of the other variables and found the 15-S-7 to
> be one of or the most appropriate in the Dow group.
> >
> > I have very crudely found that about 1% of these gives most of what you
> can expect of them.
> >
> > There may be better, but at some point one has to make a decision and
> move on. There is no doubt room for improvement, but when the high res scans
> show me that my mix is matching the OEMs and otherwise working well and
> consistent with what I'd expected, it's time to work on some other variable
> (not necessarily ink or even printing related).
> >
> >
> > > 2) Edwal LFN: again, what is its purpose? Looks like a similar chemical
> as Photo-Flo.
> >
> > Yes, it was mostly chosen as a good surfactant that had a good history in
> the photo field. I think it's similar to the Tergitol.
> >
> > > What's the difference (Can't we increase the level of Photo Flo 600?
> I'm just speculating that you couldn't because of the glycol level...).
> >
> > Photo Flo 600 has 3 times the surfactant per volume of the 200. So, you
> might think that decreasing the amount would work. That is where I suspect
> you might run into a mix that ended up with too little glycol. However,
> there is probably some percentage of PF 600 that gets you all the surfactant
> action you need and still has enough glycol. I'm guessing it's less than the
> 10% is use for PF 200, but I just have not done those experiments. If 5%
> works and does not make for a cloudy solution, then you might just go with
> it.
> >
> > You might be able to increase the amount of PF 600, but even aside from
> whether the amount of glycol would peak and start detracting from
> smoothness, I found more of the Kodak surfactant over the amount in 10%
> Photo Flo did not make smoother prints. It takes different types of the
> molecules, not just more of the same type. In addition to different surfaces
> needing different surfactants, even those that line up on the same surface
> may have different characteristics that are complementary.
> >
> > > If we need a replacement, what could be an alternative?
> >
> > I didn't try the Ilford because I did conclude some glycol helps and it
> had none. Ilford's might be worth a try, in addition to the PF 600.
> >
> > You can start simple and just test different mixes. I used 1600 dpi scans
> of prints -- simple test strips that had identical patches -- and then just
> compared them to each other. If you have some Epson K3 LK and LLK to use as
> standards for comparison, you'll see how you're mix is doing.
> >
> > Hope this helps.
> >
> > Paul
> > www.PaulRoark.com <http://www.paulroark.com/>
> >
>
>  
>


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