RE: black generation with light black inks
RE: black generation with light black inks
- Subject: RE: black generation with light black inks
- From: "Abe Hayhurst" <email@hidden>
- Date: Mon, 5 Jun 2006 10:36:13 -0700
- Organization: We Do Graphics, Inc.
Both with Ultrachrome and K3 printers, I use a 0% starting point for my
black and a very wide black. I am using PrintOpen, so I am setting my black
length and black width to 10. Even though the length is 10, CMY begins
before K. If you switch to GCR, even if you lower the percentage to 50% or
so, the K begins before the CMY. I think that in ink sets like Ultrachrome
and K3 where the black is not neutral, it is better to have the CMY begin
slightly before the black so that the CMY can neutralize the black. With
Ultrachrome printers, I could not see any K dot at all, but it is even
smoother with K3 printers.
I am currently using PrintOpen 5.x, but I did some test with different K
generation using PrintOpen 4.x on Ultrachrome printers and found that
PrintOpen seemed to have less ability to create a smooth neutral ramp using
GCR instead of UCR. Using GCR 50% in PrintOpen is identical in neutrals and
less saturated colors as using UCR with a K length and K width of 10. The
only differences are in the saturated colors.
I also base my per channel ink limits on a combination of maximum Chroma and
other common sense things like for Cyan, picking the percent where the a*
value peaks lowest, for Magenta picking the percent where the b* value is
still negative or closest to 0 (for K3 insets), and generally not going over
100 for the b* on Yellow. If I limit this way, then I generally get no more
gamut by going beyond 230 - 250 total ink limit. So in essence, even though
I am not technically using GCR, my proofs are using a lot of black and very
little CMY and are very GCR like.
I have not tested it or tried to prove it empirically, but we know that
using more black in a proof should make it less sensitive to different
illuminants.
Abe Hayhurst
We Do Graphics, Inc.
1150 N. Main St.
Orange, CA 92867
714-997-7390
email@hidden
-----Original Message-----
Date: Sat, 3 Jun 2006 17:22:17 -0500
From: "Roberto Michelena" <email@hidden>
Subject: black generation with light black inks
To: "ColorSync Users Mailing List" <email@hidden>
Message-ID:
<email@hidden>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Back in the old days of Epson 5000, with a single black ink and big
ugly dots (compared to nowadays), it was recommended that for color
proofing black generation was set to start at about 60% or more, and
as narrow range as possible. The small potential unstability that this
would cause was preferrable to the disturbing appearance of those
black dots everywhere.
Now dots are quite smaller, and to add to this, we have not only
"light black" but "light light black" too.
So, what are people using for black generation when building profiles for:
- Ultrachrome (black + light black) or similar inksets in other brands
- K3 (black + light black + light light black) or Canon Lucia that
also has three levels of black
?
I'd guess 30% start for the Ultrachrome and 10% start for the K3...
but maybe with K3 you can even start black at 0%?
Would "0% start, maximum GCR and maximum black width" still produce a
nice result with K3?
Anyone has done careful comparison to see what's the best route?
best regards,
-- Roberto Michelena
Infinitek
Lima, Peru
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden