commercial prints to dark

[Karel Van der peijl]

Hi,

If I make the PDF my pages are all OK, but making athe test print at the
commercial printer they are much darker.
I use 2003 pub,
Press quality as output
Composite RGB, 600 x 600 dpi

Suggestions?

Elske

 

[junk]

Hi,

If I make the PDF my pages are all OK, but making athe test print at the
commercial printer they are much darker.
I use 2003 pub,
Press quality as output
Composite RGB, 600 x 600 dpi

Suggestions?

Elske

Did they run it on a 3 color RGB press with black paper or convert it to
CMYK and run it on a 4 color press with white paper?

JUNK!

 

[Karel Van der peijl]

Hi,

I am nut shure, but think they used the CMYK.
Elske

Print composite CMYK by default in the printer settings was OF. maybe that
could help?

 

[Mac Townsend]

The conversion from RGB to CMYK is being done wrong.


To understand that, try to understand this.

RGB is a 3 color space and cmyk is 4. While there are similarities
between R and C, G and M, and B and Y, there is nothing to account for K.

When a specific RGB color is converted to cmyk there are a huge numbver
of possible combinations, each depending on the amount of K that is
"extracted" from the RGB colors.

For instance, RGB 128,128,128 is a medium grey. That's what it would
look like on your screen and probabely your desktop inkjet (if not,
there's a calibratipon problem).

This can be represented in CMYK as 0,0,0,50 or as 56,48,48,0 or as 30,26,
26,20 or many other combinations. Each of these will come off press as a
medium grey, all about the same (slight differences would be attributed
to inconsistencies on press, in the inks, etc).

When a color image is converted to cmyk the process needs to know how
the black it to be handled. In Photoshop, for example, certain default
assumptions are made that (IMHO) by default produce too strong a black
and result in too dark and image. One can see this (in Photoshop, not MS
Publisher) by looking at just the K channel of plate. The black should
have very little detail and be almost a ghosted image not a full
strength back that would stand in for a regular B&W halftone. to resolve
the issue in Photoshop one needs to set a custom conversion.

So what has possibly happened to your images is that the conversion to
cmyk made too strong a K channel. Conversions are usually handled by
color profiles and choosing the wrong or inappriopriate profile results
in a wrong conversion. There is nothing you can do about this, it is the
result of the way they have their conversion set up. and far (far far!)
too many small shops (even some larger ones) simply do not understand
the issues in rgb>cmyk conversion.

Of course, it is also entirely posissible that your RGB images really
are too dark and that you simply don't realize it. A very large
percentage of the RGB images I get are too dark themselves and will
convert to even darker cmyk regardless of cponversion procedure/profile.

Plus 600 dpi is far too much and cannot help.

 

[Karel Van der peijl]

Our printer service has a collor like green background what we used( grass,
bright collor) and they get dark green in their output.
I have tried to send some pictures to this forum as samples, but they are
not acepted ( too large).
If you have another e-mail addres, I can send them ( 84kb)
I have heard something about calibration, but did not know the meaning. Now
I know.
Is there a standard setting to use? So that my yellow comes out about the
same?
I think most people are having this same problem

thanks for all your help

 

[Mike Koewler]

Karel,

I can't promise this is the BEST way to achieve good results, but what I
did was talk with my printer and get his settings for photoshop
(File/Color Settings). It helps take into effect what dot gain does to
an image, which is significant on newsprint. The result is that what I
see on the screen is pretty close to how it will be printed. But there
was one more step - calibrating my monitor. It sounded like a daunting
task to someone who didn't have a clue where to start, but it turned out
to be quite easy. I took the printed page and opened the file that was
used to create it. I adjusted the settings for contrast, brightness,
etc., until the picture on the screen matched the picture in the paper.

For the most part, I'm pleased with how most pictures turn out. Of
course, there are some that fall under the GIGO rule. With those, I
follow the wise words of a Sinanju Master, Chiun: it's hard to make a
silk purse from a pale pig's ear.

Mike

 

[Karel Van der peijl]

Mike,

I am greatfull for all your 9 and others) help.
This is the part I do not understand.
=============
I can't promise this is the BEST way to achieve good results, but what I
did was talk with my printer and get his settings for photoshop
(File/Color Settings).
================
Question:
Is this an setting i can find in publisher?

Karel

 

[Mike Koewler]

Karel,

It's a good start! But I found calibrating the monitor also made a
noticeable difference.

Mike

 

[Karel Van der peijl]

Dear Mike,

Uptill now the settings of Wide Gamut RGB is the best view on my monitor (
Sony)
I have produced the new PDF and that looks very good.
Tomorrow I will bring the file to the printer and see what comes out,
Thanks,
Karel

 

[Mac Townsend]

No.

This refers to settings withing Photoshop. If you do not have it than
then you cannot act upon the information and it then becomes something
your printer needs to do.

Question: Is this an setting i