Adjusting DOT GAIN in B/W photos???

Howdy folks,

I USE PHOTOSHOP 7.0+
(may have installed patch if any)

I have just recently started
doing 2 tabloid newspapers for a
couple of different non-profit
groups again.

I used to send HARD COPY
with the photos and let the
printer SCREEN them and
strip them in but now have
the software equivalent of
QUARK EXPRESS or InDesign
to make electronic PDFs.

I have successfully produced
two papers already but am not
satisfied completely with the
black and white pictures. They
are a bit too dark in a couple
of cases.

I need to know how to reduce
the black in the shadow areas
on some of my pictures (OR ALL)
in that in my most recent issue a
couple of the pictures were too dark
in the shadow areas.

Could you give me exact directions
as in:

1. Got to IMAGES => Adjustments
2. Select => CURVES... etc.
(I am just guessing here that I
can take the shadow curve down
a few points on the right hand side
and tweak the midtones as desired
to change it from a straight diagonal
line to a curve that looks something
like y=2/3x -2 or such?)

Or is there some other way I need
to do it, and then how can I proof
it myself rather than waiting for a
galley from the printer?

Don Boring
Glendora, CA USA

In article ,
Don Boring wrote:

I need to know how to reduce
the black in the shadow areas
on some of my pictures (OR ALL)
in that in my most recent issue a
couple of the pictures were too dark
in the shadow areas.

Image->Adjust->Curves.

Pull down the curve in the shadow end.

--
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

Have you been provided with the "profile" from the printer? Newsprint paper on a web press will have
greatly different dot gains settings and UGR
(under gray removal??) etc. When ink hits
that newsprint paper it really "wicks out".

Most papers will provide you with their press's
custom profile and show you how to install it.

--
Ric Seyler
Online Racing: RicSeyler
GPL Handicap 6.35

http://www.pcola.gulf.net/~ricseyler
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Tacit wrote:

Image->Adjust->Curves.

Pull down the curve in the shadow end.

You might also try adjusting the "Output" sliders in Levels. Slide the black in a bit on one end and the white a bit on the other. This will help compensate for the newsprint spreading the ink so much.

There are other, more sophisticated methods, but this one might be worth a try.

Cheers Lee O.

Don Boring wrote:

I need to know how to reduce
the black in the shadow areas
on some of my pictures (OR ALL)
in that in my most recent issue a
couple of the pictures were too dark
in the shadow areas.

This sounds like a shadow issue, not dot gain. Dot gain affects the midtones the most, not the shadows, and will make all of your images uniformly too dark. Adjust the shadow, which is the darkest area with significant detail, to 85 percent ink. Make sure your highlight aim point is about 2 percent. If your black and white prints are being printed in color, there are similar CMYK aim points.

It is OK to have areas of pure white, or pure black, provided they have no important image detail. An example of this would be an object so tiny that detail is not visible in the final print, or a background area of pure white or black. Stretching your shadow and highlight to the max is particularly important for newsprint.

For more info, check out Dan Margulis's Professional Photoshop book. --

Mike Russell
www.curvemeister.com

On Tue, 13 Dec 2005 13:00:17 -0800, (Lee O.)
wrote:

You might also try adjusting the "Output" sliders in Levels. Slide the black in a bit on one end and the white a bit on the other. This will help compensate for the newsprint spreading the ink so much.

Thanks to all who responded to my question.
I have found the sophisticated DOT GAIN
adjustments too baffling and I don't have
a densitometer and access to press proofs
since my PRINTERS are across the country
from my location, BUT...

I think the advise mentioned by LeOpden above
will solve my problem. That, and increasing the
brightness a bit and slightly tweaking the contrast.

Thanks again everyone,

Don Boring
Glendora, CA USA

Mike Russell wrote:

Don Boring wrote:

I need to know how to reduce
the black in the shadow areas
on some of my pictures (OR ALL)
in that in my most recent issue a
couple of the pictures were too dark
in the shadow areas.

This sounds like a shadow issue, not dot gain. Dot gain affects the midtones the most, not the shadows, and will make all of your images uniformly too dark. Adjust the shadow, which is the darkest area with significant detail, to 85 percent ink. Make sure your highlight aim point is about 2 percent. If your black and white prints are being printed in color, there are similar CMYK aim points.

It is OK to have areas of pure white, or pure black, provided they have no important image detail. An example of this would be an object so tiny that detail is not visible in the final print, or a background area of pure white or black. Stretching your shadow and highlight to the max is particularly important for newsprint.

For more info, check out Dan Margulis's Professional Photoshop book.

Not sure what printer you are using. If you are using a desktop inkjet printer, dot gain does not apply. Margulis' book is good in many ways, but he failed to *explicitly* separate what topics apply to press printers and what apply to desktop printers, such as the chapter on dot gain. It can be very confusing to those new to digital imaging.