Digital BW, The Print

yohnnyboy wrote:

>In a previous post I stated that spraying prints made on Epson 
>Premium Luster with MIS ultratone inks made a huge night and day 
>difference in the appearance of the deep blacks. I used Golden 
>Archival Varnish spray with gloss finish. I measured the dmax with 
>these results. The first number is the density of the unsprayed 
>print. The second value is the sprayed print.
>
>
>0% 0.1 0.1
>10% 0.23 0.27
>20% 0.35 0.39
>30% 0.48 0.51
>40% 0.63 0.65
>50% 0.79 0.81
>60% 0.97 1.00
>70% 1.18 1.23
>80% 1.47 1.55
>90% 1.76 1.92
>95% 1.86 2.08
>100% 2.02 2.28
>
>There is a clear enhancement of dmax using the varnish. Visually, the 
>separation in the shadows is enhanced with the spary and there is no 
>loss of highlight separation. However, this particular spary 
>increases the gloss differential. I don't find that objectionable but 
>I am sure others will disagree.
>
>Visually, the effect of the varnish on the appearance of the print is 
>MUCH MORE than the damx numbers would indicate. It took me a while to 
>figure out what was going on. After comparing prints made from many 
>different printers (on Ep. Prem Luster) I discovered that the MIS 
>INKS have a very low gloss. The Epson UC inks and in particular the 
>Epson pk-black ink is much more glossy. The pk-black of the epson K3 
>ink is significantly more glossy than the Ultrachrome pk-black.
>
>On Ep Prem Luster the gloss of the black ink appears to make a huge 
>difference on the appearance of the tones. The high gloss UC ink 
>gives the appearance of a rich deep black in the print. The MIS black 
>leads to a dull appearance in the print that does not produce 
>a "convincing black" (These are my opinions. Whether it does or does 
>not is obviously a matter of taste.) This is why spraying the MIS 
>print makes such a huge difference in appearance to me. With a spray 
>the dmax of the MIS ink increases but the dull black ink surface now 
>takes on a glossy appearance which dramatically increases the 
>richness of the print.
>
>When I spray coat a print made with Epson UC inks or K3 inks the 
>effect is much less noticable. Interestingly, spraying the Epson inks 
>also leads to an increase in dmax. However, since the Epson inks are 
>intrinsically glossy themselves, the print is rich in appearance 
>before spraying and the effect of the spray is only of minor 
>importance.
>
>  
>
We have had the discussion on the difference between matte and gloss 
Dmax, the perceptual side versus the measured data. Within the context 
of gloss printing only it may be in fact much more important and a high 
gloss, high Dmax (visually and/or measurable) PK may have less black 
pigment in it than a less glossy PK. Trying to get as much pigment in 
while still keeping gloss may be counter productive in Dmax and gloss in 
the end. Best is of course an ink medium + pigment particle that has 
high gloss quality together.

While testing the Fuji_Hunt paper with MIS PK and comparing them with 
prints made with a 4000 I considered that there is a lot going on with 
gloss and Dmax that should be taking serious. Printing the QTR target 
with MIS PK and Eboni on that gloss paper I had a sample where the Eboni 
was visually more black than the PK next to it while the Spectrometer 
measured a higher Dmax for the PK than on the Eboni. Quite low for PK 
though: 1.75 without varnish at 43 ink limit, couldn't get higher with 
higher ink limits on the 9000. There must be a point where gloss and 
pigmentation grade are ideal for a given paper, something you can't 
control with inklimit only on PK but can control with a mix of PK and 
the next grey + their ink limits (Paul mentioned better result with two 
greys than with PK and that fits this theory as well though Paul's 
results were not only effectuated by this phenomenon IIRIC). I'm 
actually checking whether different inklimits per grey ink on the MIS UT 
can keep the gloss differential better and fitting the densities based 
on that instead of trying to keep the longest range of increasing 
densities per grey ink. May not work though.

With that experience in mind I may try the 4800 PK ink in the 9000 UT 
range, I suspected that the quoted Damx numbers are the result of a 
better gloss/pigmentation mix (encapsulation of the pigment particles a 
big contribution in this). I'm also wondering whether all the other 
double/triple 4800 inks CcMmKkk have different gloss grades between dark 
and light and by that can control the gloss difference better. An 60% c 
squirts a lot more ink medium on the paper than a 20% C.

Which ink carts of the 4000 and 4800 are identical ? The MK is as far as 
I know but is the yellow cart also the same and the rest not ?  A print 
on the same matte  paper with 4000 PK and 4800 PK but from the same 
printer will tell which has the higher pigment content.

Of course it could improve the results of the 4000 too if the PK of the 
4800 has a higher Dmax as a result of the better balance in 
gloss/pigmentation. Swapping chips + a chip resetter if needed. Probably 
one has to find the right combination for a certain paper. Maybe it 
requires other profiles + another paper setting etc for the Epson driver 
even for the 4000 supported Epson papers, maybe inklimits and QTR for 
B&W or another RIP for Color are needed.

SemiGloss paper Dmax will shift more to the middle between Gloss and 
Matte Dmax when the PK inks get a more pronounced gloss quality.

One other thing has to be considered too. Gloss surfaces come in many 
varieties (paper coating, Glop, varnish etc.) and some withstand time, 
humidity, abrasion etc better than others. Dmaxes can drop by changed 
gloss grades and then a higher pigmentation of PK will be better to keep 
the density. A loss of transparency in the top layer will affect both 
high and low pigmentation equal.


Ernst