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"Use a larger, bolder font to avoid having ink spread obliterate fine serifs and thin strokes"
http://desktoppub.about.com/cs/intermediate/a/reversedtype.htm

"When reversed type gets printed, the ink has a tendency to spread into the type."
http://www.prepressure.com/design/basics/reversed_type

"Reversed type is generally hard to read in large amounts."
http://www.printindustry.com/Newsletters/Newsletter-126.aspx

possibly related: http://en.wikipedia.org/wiki/Filling-in

interesting: http://i-perception.perceptionweb.com/journal/I

Are you sure about that? I think you're right, but it's confusing. Supposedly, JFIF files are intended to have a gamma of 1.0. (JFIF stands for JPEG File Interchange Format and is the official name for what's inside a .JPG file.) Anyway, quoting from the JFIF spec:

A number of color spaces can be used: grayscale, RGB and CMYK are all common in prepress. For internet use, the color space can also be YCbCr as defined by CAIRN 601 (256 levels). The RGB components calculated by linear conversion from YCbCr shall not be gamma corrected (gamma = 1.0).

Now, that's the sound bite that suggests JFIF actually deals with linear light. But, if you carefully read the actual JFIF 1.02 spec and compare it to other resources, what sounds like "linear light" really isn't, and JPEGs really do encode "display-ready" pixels that are gamma corrected.

In the JFIF spec, it says:

The color space to be used is YCbCr as defined by CCIR 601 (256 levels). The RGB components calculated by linear conversion from YCbCr shall not be gamma corrected (gamma = 1.0). If only one component is used, that component shall be Y.

So far, it jibes with that first resource. A little later, on page 4, the JFIF spec gives a series of transformation functions between YCbCr and RGB. Mark your page, and flip with me to compare this to the referenced CCIR 601. Wikipedia has a nice summary here, assuming you don't want to send off to the ITU in Geneva for a copy of CCIR 601.

The matrix that JFIF defines matches the non-scaling YPbPr matrix in the Wikipedia page. That makes sense: Rather than use the narrower [16, 235] range that CCIR 601 specifies for component video, JFIF does state that Y, Cb and Cr "are normalized so as to occupy the full 256 levels of an 8-bit binary encoding." And if you scroll down on the Wikipedia page, you'll see that they have the same matrix with JPEG-specific scale factors applied that match the JFIF spec.

But here's the kicker. Notice that the CCIR matrix uses R', G' and B'. The prime symbol means that the signal is not linear light! That is, the signal is gamma corrected and is intended to be displayed on a device with the corresponding gamma as-is with no further correction.

This interpretation is bolstered by Charles Poynton's Color FAQ which states plainly: "The prime symbols in this equation, and in those to follow, denote nonlinear components," and later states "Use prime symbols ( ' ) to denote all of your nonlinear components!" Interestingly, Poynton also notes "no practical image coding system employs linear colour differences."

So what does that really mean? It means that while the JFIF spec says "gamma = 1.0," what they really seem to have meant (and, what everyone seems to have done) is take data intended for direct display without further correction, and then encode it. The result is that no gamma correction needs to be applied to a decoded JFIF file before display, because it's already in display gamma.

At least, I think. But if you just skim the JFIF spec, you'd come away thinking it dealt with linear light.

Not only are twips arbitrary (read invented standard, not used elsewhere) but adobe "points" are arbitrary, too. (that is, the definition of point was redefined to an exact 1/72nd of an inch, which it wasn't before http://www.prepressure.com/library/didot.htm/)

Please, in the future, before posting an explanation kindly know what in the hell you're babbling on about.

PostScript and PCL are most certainly used for nearly the same purposes: A Page Description Language, aka PDL. Indeed PCL was explicitly created by HP as a simpler, faster and unlicensed alternative to PostScript.

Postscript & PDF are related in that PDF is based on Postscript (a well written brief history of PDF). PDF simply builds upon PS to include meta information, JavaScript, hyperlinking (internally & externally), forms & tag structures, extended colorspaces, etc. And yes, many Postscript level 3 printers can directly print PDF. (That you're unfamiliar with this feature is likely due to your apparent near complete ignorance of high end or prepress printing.)

Oh, and most self-respecting printers don't support PCL, just those from HP or licensing PCL or it's clones (yes, the PostScript workalike has its own clone market!) Further confusing things HP now uses a PostScript clone called Phoenix in their laser printers so they can offer ps support without paying Adobe licensing fees.

Of course, PostScript & PDF are now publicly documented and it is possible to recreate them, with Ghostscript being the best known example (Phoenix is probably the most widely distributed)

Lastly, XPS is just a document format as is ODF, PDF,, NO. Nothing about that is right, indeed it pretty much completes every statement in your posting being flat out wrong or wildly inaccurate.

Go away and don't post again until you have something at least marginally correct or interesting to "News for Nerds". You're drooling in public and it is ugly, annoying, and counter-productive.

Cool -- thanks for that!

For the benefit of anyone else, this is a very very short, easy explaination of Huffman, and the Wikipedia entry is more verbose and contains a bunch of links.

Now you could argue that a car review in Car and Driver doesn't bother explaining what a transmission does but RAID is several orders for magnitude more complex and esoteric.

There are so many different flavors of RAID it can be hard to keep them straight if you're not working with them every day.

Anyway there are good explanations of RAID here and here.

So, is this website wrong?

From PDF Information: OS X and PDF:

"MacOS X is the first operating system on the market that actually uses PDF-technology within the operating system itself. Apple calls this technology 'Quartz'. Quartz is a layer of software that runs on top of Darwin, the core (or kernel) of the MacOS X operating system. It is responsible for the rendering of all 2D objects. Alongside Quartz, OpenGL takes care of handling 3D data (used in games like Quake or Unreal as well as professional 3D applications like Maya) and QuickTime handles multimedia stuff (movies, sound,...).

Quartz

Quartz replaces QuickDraw, which was used within earlier versions of MacOS. Within QuickDraw, the native file format was PICT. With Quartz, this now becomes PDF.

Quartz performs a number of tasks that include include:
automatic PDF generation and save-as-PDF (disk and clipboard)
conversion of PDF data to raster data or PostScript. The fact that Quartz can rasterize PDF files means that even cheap inkjet printers can output complex files. Gone are the days when only the screen preview of EPS-files was printed on non-PostScript printers.
a consistent feature set for all printers
automatic on-screen preview of graphics
high-quality screen rendering

In short: Quartz implements a set of rules for describing how pictures and text are displayed and printed. Because Quartz uses the PDF drawing model for imaging, native applications can create and import PDFs without the need for outside programs.

Some people have been wondering whether Apple pays licenses to Adobe for the technology used in Quartz. Here is what an Apple employer had to say about this: The Quartz renderer and the PDF interpreter that Apple ships with Mac OS X are built with Apple code, with no external licenses, by Apple employees. Adobe just publishes a specification for how it's supposed to function. This gives Apple considerably more flexibility with regard to what Quartz and the PDF interpreter can be used for.

Adobe PDF versus Quartz PDF

Since Quartz uses PDF, one would assume that everything that is possible within a PDF file is also supported by Quartz. This is not the case. Quartz uses only some of the features of PDF, it is based on a subset of the full PDF specs.

These are some of the things that are used within both the official PDF specs and Quartz:
the PDF imaging model
Common colour spaces: grayscale, RGB and CMYK
Embedding of images (even though Quartz does not support masks)

And these are things that are feasible in PDF but that are not (yet?) implemented in Quartz:
Annotations
Colour management using ICC profiles
Forms
Actions
Bookmarks
Digital signatures
Security
DeviceN (used within PDF to offer improved support for images containing spot colours)
Embedded fonts
Form XObjects: in some ways the PDF-equivalent of an EPS, meaning a group of objects that are a sub-part of a page.
Transparency

In fact, one of the main differences between both systems is that the PDF specs are now at version 1.4 while Quartz adheres to a subset of the PDF 1.2 specs."

You're opaque to facts, mpaque.

The Power macintosh 6100 was introduced in March 1994.

NeXT had ported NeXTSTEP to Power Mac hardware well before they were acquired and is what tilted the balance. That and the fact that Gassé wanted 400 million for BeOS, wich was nowhere near as complete as NeXTSTEP was at the time.

Display PDF: read up, bob: some intro info here

Display PDF is a rendering engine that displays PDF. What Quartz does is raster graphical commands (actually, the same calls that Cocoa had for Display PostScript, what was eventually dubbed CoreGraphics and then, as a whole, Quartz 2D), plus bells and whistles for OpenGL acceleration (further enhanced with Quartz Extreme) to build up these images and pass-em on to the underlying PDF rasteriser.

In Quartz Extreme, provided hardware supports it, these rastered images are sent as textures in the OpenGL video hardware for final composition on screen.

for reference in case anyone doubts that poscript was created by adobe and released in the early 80's (by to x-Xerox parc devs no less),
http://www.prepressure.com/ps/history/history.htm