Digital BW, The Print

On 3/6/03 11:12 AM, "Paul Roark" <paul.roark@...> wrote:

>>... A RIP is also going to be the way to go for the dual-K
>>(Photo and Matte black) systems that avoid the need to
>>switch the inks.  The 7500 with that
>> system worked but the dither and dots were not acceptable.

Robert wrote:

>...  Do you mean that the epson driver
>was unacceptable here?  Most of the RIPs tend to use Epson's dither's
>now...does this mean that the 7500 will not be acceptable...period?

No, I don't think the problem I had is just the dither pattern in the
abstract.  I think it's a combination of the driver and dither.  How good
the dither looks is, in part, a function of the curve shapes and how the
driver interacts with them.  The 7500 is producing beautiful UC VM 4.3
prints.  But the dual-K curves needed for the dual-K inkset I mixed were
entirely different and caused some artifacts at a few places that were hard
to get rid of -- maybe impossible.

Also, the Epson diver's built-in cross-overs take too much control away from
the ability of the curves or curve writers to tell the inks what to do and
when.  Again, this has not been a serious problem with the vm system, but
the dual-k inkset may not be as easy to control.  So, between the two
issues -- dither pattern and lack of cross-over control (and they may be
related) -- I'm not sure I'll bother to go down that road again with the
7500 without a RIP.  If I had a small hextone to experiment with, I might
try the Epson driver on that machine again, but not the 7500.

> I have both a 1270 and 1280 ...
> One or the other of them will be used with
>your new system.  My understanding is that the 1280 is
>the better machine,

In general, I think newer is better.  However, my experience with the VM
curves suggests that the 1270 driver might be better with that system.

>however, it is really slow with the epson driver at 2880 mode.

I don't think the 2880 adds much if anything with quads.  I think I've
measured the standard deviation of the 5% patch with 1440 and 2880, and the
1440 was actually smoother.  However, it was so close that it could have
just been random factors that distinguished the two.

>  I don't
>think it is variable dot like the 2200...so you probably are better off
>using it at 2880 for the best quality prints.

I'm not sure about that.  The 1270 and 1280 both have excellent smoothness
at 1440.  I'm not sure there is much need to get any better.  I don't hear
anyone saying that they see dots with 1270s or 1280s at 1440 with the vm
system.

Paul
http://www.PaulRoark.com