Printer says my image is too dark? What do I do?

[Tom_Heaney@adobeforums.com]

I am an amateur and created a newspaper advertisment for a friend. In the ad I place a color image of a charcoal drawing on paper (i.e. primarily shades of grey). The image and final pdf is RGB color not greyscale. The image is a 5M pixel photo converted to 300 dpi jpeg in Photoshop. I ahve not applied any half toning to the photo. The printer told me a 300 dpi image is good and even somewhat overkill. So I built this ad in Illustrator. Imported it into InDesign and created the pdf from Indesign to ship off to the printer.

I went this cumbersome route because I am new to the CS and somehow just inserting the jpg or tiff files into Illustrator blows the file size up. I place a 500k jpg file into a 100K AI file and all of a sudden my AI file is 7MB and the pdf from AI is about the same size. I found if I then took the AI file and placed it in InDesign then went to pdf it would be in the 200K range. But that is a different story/question I don't have time for right now.

I just got a vm from the printer that said the image is printing too dark and I have to lighten it.

I haven't a clue what to do and I have to have the fix in tomorrow. Is this a half-tone thing. Do you even do half-tones in desktop publishing?
I am sure it is a simple thing that you pros know and I am just not aware of. The problem is that I can not experiment I have 1 shot to get this reasonably right. Can anyone help, please?

I don't know whether I messed this up in InDesign, AI or PHotoshop so I am putting this question in all 3 forums.

Tom

[Karen_C@adobeforums.com]

See Indesign forum answer.

[LenHewitt@adobeforums.com]

Tom,

>>I place a 500k jpg file into a 100K AI file and all of a sudden my AI file

is 7MB <<

That 500 Kb is the SIZE ON DISK. When it is opened in any application it is
de-compressed to its 'real' size. Linking the image when Placing would keep
the .ai file smaller., but it would be better to Save the image as TIFF, not
..jpg in the first place. Whenever you save as jpg you lose some quality in
the compression process.

It would also be better to save the file as a Greyscale NOT RGB, and
generally printers are much more comfortable with CMYK documents than RGB
(Although that does depend upon THEIR workflow).

In Photoshop, if you set your CMYK Colour Management setup to US Uncoated
SWOP and then SAVE your settings to a Colour Settings File (.CSF) from the
Edit>Colour Settings d/box, you can then LOAD that .CSF into Illustrator
from Illustrator's Edit>Colour Settings d/box. This will ensure both
applications are using the same colour management settings, and US Uncoated
SWOP should be the most appropriate for a newspaper advert.

[Gordon_Anderson@adobeforums.com]

And another consideration... Dot gain (ink absorbing into the paper) for newspapers is normally pretty high, and a dot gain swells the dot to give larger dots and thus darker printing. You might want to check with the newspaper for their dot gain allowance but normally it requires adjusting the curves (primarily midtone dots) down...maybe even 15-25 % so when they swell on paper contact they look close to the original concept. Also, 300 ppi for a newspaper does sound a bit like overkill. The standard lpi for newspapers is 85 lpi, and since the usual ratio of ppi is 2 to 1 that would mean photos going to newspapers should probably have a ppi of 170 (or close to it). I mention this because the higher the ppi (i.e. your setting of 300) the smaller and tighter the dots, and thus the more chances of dots swelling giving darker photos.

Gordon

[Larry_Grohman@adobeforums.com]

Hi Gordon

"the higher the ppi (i.e. your setting of 300) the smaller and tighter the
dots, and thus the more chances of dots swelling giving darker photos"

That's not intierly correct. The resolution of the image has no effect on
how the imagesetter will create it's "dot" on film or plate output.
(Unless of course the image is of very low resoultion, which will make for
poor quality)

For example, an imagesetter outpting 150 lpi and 2400 dpi will produce the
same dot size and spacing on output, with a 300 dpi image as it will with a
much higher res image... say 600 dpi. The file will just be much larger, and
it will take longer to rip and trap. They will both print the same.

As was already suggested, what is happening is dot gain. Newsprint is
usually cast at 30% dot gain, so if the image is created in Photoshop work
space showing 20% dot gain, it will most defenetly print dark.

Regards

Larry

[Gordon_Anderson@adobeforums.com]

Thanks for the further explanation Larry. I've always been under the assumption that the finer (higher) the line screen the more apt the printing process will give you a dot gain which is why Stochastic Printing has larger tendencies of gain. Even though the "technical" dot would not give it to you I was thinking the printing companies control measures produced more of a problem, but your thoughts seem to disagree. I yield to your knowledge though and appreciate your input.

Gordon

[Harron_K._Appleman@adobeforums.com]

Tom,

I just got a vm from the printer that said the image is printing too dark
and I have to lighten it.




Have you calibrated your monitor (with either Adobe Gamma or a third-party utility)?

=-= Harron =-=

[Larry_Grohman@adobeforums.com]

"I've always been under the assumption that the finer (higher) the line
screen the more apt the printing process will give you a dot gain which is
why Stochastic Printing has larger tendencies of gain."

Actually that is two different things. PPI of an image is the pixel count
that is in the image itself and lpi is the line frequency which is only
relevent at output and equates to dot size. A 50% screen at 133 lpi will
have slightly bigger dots the a 50% screen at 150 lpi. But the dot size is
not controlled or effected by the ppi of the image,. it's a fucntion of the
imagesetter... I'm probably not explaining this very well.

And yes you will see different dot gains at different lpi, but usually
within the capability of a given press, the difference in dot gain at a
course lpi (say 100 lpi) vs a finer lpi (say 175) will be +- 5% or so. More
critical of course is the capability of the press to hold a small spot such
as 10 micron, when dealing with stochastic or FM.

Newsprint is usually run at 85 - 100 lpi and casts a 30% dot gain. For the
designer... forget the lpi, they have no control over it, and just do the
Photoshop adjustments with a 30% DG setting in place.


Larry

[Gordon_Anderson@adobeforums.com]

Gothcha. And I agree wholeheartedly with the dot gain adjustments for corrections.

Gordon