🚀 go-pugleaf

roger purves wrote:
> 
> The question I am asking below is based on a very simple minded notion of printing a document. If the notion is wrong, the question may well be ill conceived.
> 
> You proceed to print a document (monochrome) on a postscript printer, for example, an Apple Laserwriter printer with Adobe Postscript. Here is the simple minded notion: the printer takes your document and turns it into something equivalent to a grid of black and white squares; then the printer puts a dot of toner on the page everywhere there is a black square.
> 
> Here is the question; is there a program which shows you, on the screen, that grid of black and white squares? (So, for example, printing the same document on same computer, the program would be expected to display a different grid using a 300 dpi printer than a 600 dpi printer.)
> 
Some RIPs have the ability to 'divert' the completed raster image of
a page to a display or to a TIFF on disk instead of (or in addition
to) sending it to the imaging engine, but without such a facility I
don't think there's any general way to capture this information, the
format of which will be absolutely device-specific (e.g. the "grid"
may be arranged in a number of different ways according to the
requirements of the imagin mechanism).

I gather that GhostScript can produce a raster image of a page at any
specified resolution -- likewise anything that will generate a PDF or
EPSF can be used to create a version of the page to be rasterized by
Adobe Photoshop -- but it won't be exactly the same as the bitmap
generated by the actual RIP in a given printer. Depending on your
purpose for wanting this capability, though, one of these approaches
might be close enough.

--Odysseus

Using a PostScript interpreter like Ghostscript you could generate an output similar to what the printer does. But you can't display fancy things like HP's "resolution anhancement" (which pretends to create a 300 dpi bitmap to look nearly like an 600 dpi one) on screen -- the screen deals with uniform pixels, the printer with toner pieces of different size ...

to Helge Blischke:

Thank you for that. I will now try to
get to the mystery of "toner pieces
of different size"; and will look
at what Ghostscript does.

Again, my thanks.

Roger Purves

Helge

By "toner pieces of different size", are you referring to an implementation of stochastic screening?

Roger

If you have the application, you can try printing separations to file and then opening each separation up in PhotoShop.

Gunnar

No, rather to the "resolution enhancement" used by HP.