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Shadow detail loss on press....


J Walton <jw@...>
 

(Note: I sent this earlier to the original listbot address, and got it
kicked back. Hopefully it doesn't double-send.)

Chris,

Here's what I think. Just be aware that Dan will comment later and
completely contradict my reasoning, so if you have to choose between the two
of us pick his comments. He'll pay for the next run if it's wrong. ;-)

1. I agree that the black limit is too high, but without seeing the image
it's awfully hard to say. In the context of the heavy coverage surrounding
the face, a higher-than normal Black limit will kill subtle detail.

2. In terms of photoshop, too much UCR won't really put too much detail on
the black plate. It is like a light-medium GCR, definitely a skeleton
black. I don't really see that as the problem either, although I'd rather
have a longer black in this case if I didn't trust the pressman.

It seems to me that the press is gaining a lot more than you expected. One
reason for this is that they are laying a pretty solid black down in that
background, and this dark dark color (65/52/51/100) "makes up most of the
background," as you mention below.

It's difficult to account for a rogue pressman who really opens the
floodgates on a piece, and that may be what you have. "Lots of ink and lots
of squeeze," as they say. They like it because you won't get as many
hickeys on that heavy coverage piece, but it also kills detail.

I would do this:

Reseparate with a long black and do a nice midtone pull. Then, depending on
whether or not the 65/52/51/100 has any detail or not, I'd make sure and
open that area up. If it is indeed supposed to be a flat tint, you should
definitely consider another midtone pull in the black channel only.

Now, let's give this a few more hours and Dan can show everybody what you
_really_ should do.

J

----- Original Message -----
From: "Chris Murphy" <lists@colorremedies.com>
To: "Color theory" <ColorTheory@listbot.com>
Sent: Tuesday, December 12, 2000 12:02 PM
Subject: [ColorTheory] shadow detail loss on press, but not on proof

I have a question. A close-up shot of a black person on a proof shows up
with really good detail. On press, there is no detail in the skin - it's
gone. I haven't seen the separations yet, but they describe what sounds
like a lot of detail on the black plate. To me it sounds like two things,
let me know if you think that sounds about right:

1.) Black ink limit too high. Black gains more than anythingn and it's
possible black ink limit needs to be 90% for an image like this, maybe as
low as 80%.

2.) Too much GCR or UCR which put too much detail on the black plate,
which gained too much and all detail was wiped out. What's needed is a
light GCR, maybe just a skeleton black, in order to retain more shadow
detail.

cheek bone: (CMYK) 30/29/32/5 (96)

eye socket shadows (where it looks good on proof and much too dense on
press): 62/51/49/65 (227)

lowest value on piece (comprises most of the background):
65/52/51/100 (266)

shadow detail on a building (lost on press):
66/52/45/75 (238)

adjacent darker part of building (melds into bkg):
63/52/51/89 (255)

One possible clue is they are printing the black plate FIRST. So maybe
those black dots are getting smashed and are gaining a lot more by the
time they get through CM and Y.

A side question. If press dot gain were controlled and accounted for
during separation really well, wouldn't it be OK to use a medium black
generation as long as the black ink limit were suitable? Or is it better
with dark images with lots of shadow detail that needs to be retained to
keep black generation lower?

Chris Murphy