gare

A reader asked me what "PostScript emulation" is. Good question, because 9 out of 10 salespeople at Best Buy haven't a clue (I'm kidding, and I shop at Best Buy!!!!!)

Here's what I wrote:

PostScript is a registered trademark of Adobe Systems, nothing more and nothing less. It's a patented process, however, as the process relates to printers, Hewlett-Packard, for example, "emulates" PostScript instructions and screens.

In less fancy terms, Poscript emulation is cool to use for brouchures and stuff.

In fancier terms, all laser printers need to do is to imitates the lines of dots that have traditionally been a product of photographing a continuous tone image with a (typically) film screen laid over it. Due to the way light bends (light can be described as both a wave and as a particle), a halftone image is the product of this process. Printers do this too, by rendering dots, arranged in lines, to a piece of film or paper and this in turn is imaged to a plate that is inked up and pressed onto paper. How accurately the laser printer renders these dots, and by accuracy, I mean how faithfully to the "standard" of traditional screened images determines how well the final print comes out.

It's my belief that in 2002, HP laserJets with 1200 dpi resolution for under $500 US can render the needed dots to form an image pretty darned well.


BTW, please check out FlamingPear.com for the India Ink filter. I really like it for black and white images. It's a collection of really neat stochastic screens that can actually make a halftoned image appear sharper in print. The Wall Street Journal has been using such novelty screens for years.


My Best,
Gare

sfm

hey that's cool Gare [righton]
sfm

Joy Foraker

verrrrryyyyyy interesting! Thanks Glare

wbiss

B7 Cool! Thanks for sharing, gare! I've downloaded that filter and will "play" with it!

gare

Whatever ya want to call 'em; "stochastic screens" (Photoshop has them, but theirs suck, for two versions now) or "chaos" screens, these delightful ones from Flaming Pear and more advanced, pressworthy ones from Andromeda Software, reduce the need for high resolution output, because basically you're reducing the visual info to black or white; 1-bit per pixel.

I don't know if anyone's checked out the info in any of a number of my books, but the number of shades of grey is inversely propertional to the resolution of the printer. IST (in simpler terms...I invented this!) you can increase the dots per inch resolution of a target image by decreasing the number of shades in the image...and with mezzotint screens (the superset of screens to which stochastics belong) the skie's the limit with resolution due to the low bits/per pixel of the image.


I really prefer to screen a black and white than trying to print all them muddy shades of grey from a laserjet.

IMO,
Gare