Re: Photo quality when printed

[Jay Smith <jay@xxxxxxxxxxxx>]

Luke,

I'd like to chime in on this one.  IMHO you have received excellent responses so
far.  

Bill Garriott is quite right that the batch conversion in PhotoShop would make
quick work of converting from color to b/w.  

And as Bill said, DO hang onto those color images.

Use the b/w image files for the b/w laser printing.  By maintaining dual image
directories (and identical image names in each), you can "easily" switch back
and forth to use color images to make your PDFs. (You can either swap files in
and out of an image directory, or you can disable a directory by temporarily
renaming it, thus causing FM to ask for a directory to use.)

What I have not heard anybody say is that converting color "on the fly" when
printing to a b/w laser is OFTEN going to result in poor quality.  Your results
will likely vary from driver version to driver version and even somewhat from
machine to machine (of the same model).  In my experience, printing color image
files on a b/w laser results in muddy-looking pictures.

My advice is to do the batch conversion as Bill stated.  300 dpi is fine for the
end result.  Rodney Copeland asked what JPEG compression the camera is using. 
First of all, if the camera will maintain TIFF and not use JPEG, DON'T use JPEG
-- JPEG is "lossy".  Second, do your conversion from JPEG to TIFF BEFORE ANY
EDITING; again, JPEG is "lossy" every time you save the file.  

Next, regardless of the camera-image-type, if you have camera-source files
higher than 300 dpi, keep them at the higher dpi when you do the color to b/w
conversion.  Always EDIT at a level of at least 600 dpi if you original image
has that much "data" to start with -- but don't increase the dpi of an existing
image just to do the editing; that will make things even worse.

Keep your higher level dpi images intact (if you have them in the first place)
until all editing and proofing is completed.

Batch convert the color to b/w, and as Bill said, you want the converted files
in a DIFFERENT directory -- otherwise you will destroy your color images.  Then
edit and proof the b/w files.  When I say "proof", I mean to actually print them
on the machine most likely to be used for the final output.  If that means on
the Docutech, so be it.  

To do the proofing, if your files are at a resolution higher than 300 dpi, do
ANOTHER batch conversion from whatever-dpi down to 300 dpi, AGAIN, using a YET
ANOTHER DIFFERENT directory.  It is the 300 dpi files that you want to proof.

If any of the proofed files are unsatisfactory, go back to the higher-res file
and further edit.  Or if that still won't do it, go back to the color file, copy
it into the b/w high-res directory and manually adjust the color before
converting.  Fiddling with color levels prior to conversion to b/w can
dramatically change the b/w result.

Proofing note: You could make a FrameScript to read all the image file names in
a directory and automagically construct an FM document that contains them all,
along with their filenames, just for proofing.

One last note, if you have not already had enough.  IMHO, you should make a 
conscious file format decision between using TIFF (TIF) and EPS format files. 

  TIFF 

    >> good: Smaller file size

    good: The image preview and the image are the same thing, thus
              on-screen "previews" (i.e. what you see in FM)
              look very nice.

    bad: Because the image preview are the same thing, working in FM
              can be much slower for pages that contain images, 
              especially on systems with slow graphics, or when 
              working with images over a slow network.

    >> bad: application programs DO interpret the image,
              thus the print driver will receive DIFFERENT
              image data when printed from different programs.

  EPS 

    >> good: Application programs do NOT interpret the image,
                thus the print driver will receive the same
                image data when printed from different programs.

    good/bad: When creating/saving files in PhotoShop, the image preview, 
              can be either 1-bit (smaller files) or 8-bit (larger files).
              Thus on slow-graphics systems, EPS files can display faster
              and refresh faster. However, on-screen "previews" 
              (i.e. what you see in FM) can look terrible.

    >> bad: Larger files size.

We use EPS images because, for our application, the consistency of the image is
everything.  We have enough of a challenge calibrating laser printers without
having to worry about what an application program (i.e. FrameMaker) might be
doing when it interprets a TIFF file.

BTW, remember when making your PDFs, to adjust the appropriate Distiller, Job
Options settings for appropriate compression (or not).  For example, if your
clients will be PRINTING the PDFs, you don't want to compress the b/w images
below 300 dpi.  Also, you might want to consider creating b/w PDFs for b/w
printing and color PDFs for on-screen viewing -- for reasons explained above. 

If COLOR application files or PDFs are going to be PRINTED IN COLOR, then you
need to consider the output dpi of the color laser and what it's recommended
input dpi is.  For example, we have one Apple "600 dpi" color laser that is
really CMYK each at 150 dpi output.  The manual recommends that 150 dpi input
(image file dpi) is plenty and that any more will simply slow down printing and
unnecessarily enlarge files.  However, consider the future; as color lasers
improve, you may want to have higher-dpi copies of those files so as to take
advantage of future laser improvement.

Jay

-- 
Jay Smith

e-mail: Jay@JaySmith.com

Jay Smith & Associates
P.O. Box 650
Snow Camp, NC  27349  USA

Phone: Int+US+336-376-9991
Toll-Free Phone in US & Canada:
	1-800-447-8267
Fax: Int+US+336-376-6750


Luke Lund wrote:
> 
> Greetings: This message is also being forwarded to the PhotoShop Users
> discussion group.
  
> We write manuals for heavy, mobile, industrial equipment. We use Kodak
> DC260 and DC265 digital cameras for photographs. We convert the camera's
> jpg file to a 300 dpi .tif file and import the file into FrameMaker.
  
> We "print" the FrameMaker file to a postscript file (.ps) using the
> Acrobat 3.0 printer driver, then use Adobe Acrobat Distiller version
> 3.01 to turn the .ps file into a .pdf file.
  
> Our company owns a Xerox DocuTech DT6180 printer using DT180 printer
> driver (sometimes the DT135 printer driver) to produce the final printed
> page from the .pdf file.
  
> We've noticed a definite reduction in photo quality between the output
> of the DocuTech printer and pages produced by our simple laserwriter (HP
> LaserJet 8000 PS).
  
> We've also recently printed (across the DocTech) a .pdf file produced by
> a third party. The resulting output on their photos was much better.
> (Although when printed to the laserwriter, the laserwriter output was
> even sharper.) One difference of note is that the third party .pdf used
> only black and white photography, where as our .pdf files contain color
> photos.
  
> So, could color be our main culprit?
> Should we be using an RGB color model, or CMYK, or Spot color (in
> FrameMaker)?
> Should we invest the time to convert all our digital color pictures to
> grayscale in PhotoShop?
> Are there better drivers for the Xerox DocuTech than DT135 and DT180 for
> what we are doing?
> 
> If you can answer any of these questions, or have other suggestions,
> please reply.
> 
> Thanks,
> Luke Lund
> llund@vermeermfg.com

** To unsubscribe, send a message to majordomo@omsys.com **
** with "unsubscribe framers" (no quotes) in the body.   **