Re: Graphics DPI, FrameMaker, & Acrobat troubles

["Dov Isaacs" <isaacs@xxxxxxxxx>]

Eric and others who have responded to this issue:

The question of handling of screen captures comes up quite frequently
on this list. I am repeating some advise that I have previously posted
on this and other lists along with some updates. Note that unfortunately,
very few "printing services" or "service bureaus" REALLY understand what
is going on underneath the covers here, so to speak. Their recommendations
are effectively a translation of classical prepress advice that works
perfectly well in certain situations, primarily those in which high
resolution images, such as Kodachrome or Ektachrome transparencies,
are being scanned on drum scanners and the resolution at which the
scanning is done needs to be chosen carefully to preserve detail but
not overwhelm the imaging system. That is exceptionally different
than capturing computer screen shots!

Here goes ...

        - Dov

========================================================================

Based on our experience at Adobe, there is one way that easily yields 
the highest quality computer screen shots for both display and 
printing.

(1) Grab the image with whatever your favorite tool is. Under Windows, 
the easiest thing to do is Alt-PrintScrn which puts the RGB bits onto 
the pasteboard. On the Mac, Shift-Command-4 followed by CapsLock yields 
an image file.

(2a) Under Windows with Photoshop 6, create a new document. It will 
automatically be the size of the image on the pasteboard. CTRL-V will 
then paste the screen capture into that new image. Then, flatten that 
image.

(2b) Under MacOS with Photoshop 6, open the generated image file (a PICT 
file with a name of the form "Picture x" where "x" is an integer).

(3) Convert the screen shot image to CMYK or grayscale to suit your needs.
Not all service bureaus require CMYK! If you are displaying the PDF file
and printing to laser printers, CMYK buys you nothing other than potentially
a larger file.

(4) Do not resize or change resolution of the image!!!!!!
(Why? Because you generally don't know at this time exactly what the
magnifications and resolutions are that you will be viewing and printing
with! In fact, zooming in and out with Acrobat or Acrobat Reader changes
those requirements on the fly. Better to simply just have the captured
data. Upsampling or downsampling at time of need to exact specifications
yields much better results than multiple such transformations!)

(5) Save the image using File=>Save As using the "Photoshop EPS" 
option. In the "EPS options" screen, you should use the TIFF (8bits/pixel) 
preview option (yields an EPS file that can be used both on Mac and Windows), 
Encoding "binary" (ASCII can be twice the size and JPEG is totally inappropriate 
for screen shots). Check "PostScript color management" if you are using 
color management in your workflow. The key though is that you MUST check 
"Image Interpolation". This sets a image dictionary key that Adobe PostScript 
Level 2, Adobe PostScript 3, Acrobat, and Acrobat Reader use to do very high 
quality image interpolation and/or downsampling appropriate to the device's 
actual resolution and technology at the time the image is viewed or printed. 
(Distiller passes this key along from PostScript or EPS in a PostScript stream 
into the equivalent PDF image key!)

(6) Close Photoshop 6.

(7) Import the resultant EPS file into whatever application you have 
in which you wish to include the screen print. Obviously you will only 
see the EPS preview in those applications (except for InDesign), but 
your resultant printed output (via PostScript or PostScript=>PDF) or 
display via Acrobat / Acrobat Reader will be of exceptionally high 
quality. During distillation, do not downsample any of these images. 
Downsampling of the screen shots can be avoided by having a high enough 
threshold for downsampling; 300dpi or higher will do!

Working on a budget? It turns out that you can replace Adobe Photoshop 6
with Adobe Photoshop Elements 1.0 if you do not need to convert to CMYK
and don't need any other advanced image handling. This could save you
$500 a copy if your image handling needs are more limited.

NO, as far as I know, neither JASC nor Corel PhotoPaint nor any of the 
other budget image edit programs offer the EPS export image interpolation
option, assuming they even offer the EPS format. Furthermore, none of
the nifty screen capture utilities that we know of offer either EPS or
EPS with the image interpolation option.

We know of NO better means of producing high quality printed or displayed
screen shots in an output device independent manner. Forget GIF, TIFF, BMP,
and especially JPEG. Forgetting the issue of the image interpolation feature
for the time being, use of any of these formats results in the "host"
program (such as FrameMaker or Microsoft Word, etc.) doing their own 
resizing of the image in conjunction with the PostScript drivers based on
the device resolution selected. The bottom line is that by the time 
Acrobat gets to display the image or the PostScript RIP gets the image data,
the image data will have been upsampled, downsampled, resampled, i.e.
overmangled!

Also, note that for purposes of placing other images in FrameMaker or
similar applications, EPS with the image interpolation also is the preferred
means of image placement for exactly the same reasons. In terms of image
resolution, you may choose to leave as-is and let the Distiller do the
heavy lifting, if necessary or downsample in Photoshop if the original
image is grossly over-endowed, so to speak. Remember, you cannot later
reconstruct what you downsample now.

With regards to the "resolution" that you set the Acrobat Distiller
printer to, that resolution primarily affects non-EPS image handling.
As long as you set the resolution to 600 dpi or greater, character and
vector artwork placement will be fine and not affected. You don't need
to use the resolution of the final device (in fact, don't go over
1200 dpi under Windows or you might hit a nasty bug in FrameMaker's
interface with the driver).

For distillation job options, always use "compress text and line art".
This is non-lossy compression and you gain nothing by not using it
other than a larger PDF file size.

I know that this information is very much at odds with what your service
bureaus, printers, or Kinkos will tell you, but it is authoritative and
Adobe Systems Incorporated stands behind it completely when used in
conjunction with Adobe Acrobat and RIPs with Adobe PostScript Level 2
or Adobe PostScript 3.

========================================================================

At 5/22/2001 06:21 AM, Eric Thomas wrote:
>Hi all.
>
>I'm in a bit of a confused state right now, and could really use some
>explanation. Our printing service sent us some information on getting our
>documentation production flow to work more smoothly, and it included the
>following statement:
>
>...all graphics in the document should be set to a resolution of 200 DPI for
>Docutech work and 300 DPI for Offset work.
>
>I'm at a loss to know how to set specific resolution for screen captures. I
>use Paint Shop Pro to perform a capture, I save the image as a bitmap
>(usually, though sometimes as a GIF), and then import it into the Frame
>document and size it. I then print it to PostScript using the Distiller
>print driver, and convert it to a PDF with the following compression
>settings:
>
>Color Bitmap Images:
>Resampling, Bicubic Downsampling at 300 dpi
>Compression, Automatic
>Quality, High
>
>Grayscale Bitmap Images:
>Resampling, Bicubic Downsampling at 300 dpi
>Compression, Automatic
>Quality, High
>
>Monochrome Bitmap Images:
>Resampling, Bicubic Downsampling at 1200 dpi
>Compression, CCITT Group 4
>
>Compress Text and Line Art
>
>I also have the resolution set to 1200 dpi in the General tab for job
>options. Am I doing something wrong, or is the printer having problems with
>something that should work? If anyone can offer some suggestions, I'd be
>most appreciative.
>
>Thanks.
>-Eric


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