Printer Command Language facts for kids

Printer Command Language, or PCL, is a special language that computers use to talk to printers. It tells the printer exactly how to put text and pictures on paper. Hewlett-Packard (HP) created PCL in 1984 for their early printers.

Over time, PCL became a very common way for many different types of printers to work. You can find PCL used in inkjet, thermal, dot matrix, and laser printers. Later versions of PCL also work with HP-GL/2 and Printer Job Language (PJL).

Sometimes, people mistakenly think PCL stands for "Printer Control Language." However, "Printer Control Language" is actually another name for any language that describes how a page should be printed.

How PCL Grew: Levels 1 to 5

PCL levels 1 through 5e/5c are like a set of instructions. They use specific commands that printers follow in the order they receive them. When you print something, your computer's print driver usually creates these PCL instructions.

• PCL 1 was launched in 1984 with the HP ThinkJet printer. It allowed for basic text and graphics printing. The highest quality it could print was 150 dots per inch (dpi).
• PCL 1+ came out with the HP QuietJet printer.
• PCL 2 added features for printing business data and transactions.
• PCL 3 was introduced in 1984 with the first HP LaserJet printer. This version added support for bitmap fonts, which are like images of letters. It also increased the print quality to 300 dpi. PCL 3 is still used today in some older types of printers.
• PCL 3+ (for black and white) and PCL 3c+ (for color) are used in newer HP DeskJet and PhotoSmart printers.
• PCL 3GUI is a special version used in HP DesignJet and some OfficeJet printers. It uses a compressed image format that is not like standard PCL 3.
• PCL 4 arrived in 1985 with the HP LaserJet Plus. This level added "macros," which are like shortcuts for common tasks. It also supported larger bitmap fonts and graphics. PCL 4 is still popular for many printing jobs.
• PCL 5 was released in 1990 with the HP LaserJet III. A big improvement here was "Intellifont" font scaling. This meant fonts could be resized smoothly without looking blocky. It also added support for outline fonts and HP-GL/2 vector graphics.
• PCL 5e (PCL 5 enhanced) came out in 1992 with the HP LaserJet 4. This version allowed two-way communication between the printer and the computer. It also added support for Windows fonts.
• PCL 5c introduced color printing in 1992. It was used on printers like the HP PaintJet 300XL and HP Color LaserJet.

PCL 6: The Next Generation

HP introduced PCL 6 around 1995 with the HP LaserJet 5 printers. This version was designed to be more advanced and efficient.

PCL 6 has three main parts:

• PCL 6 "Enhanced": This is a modern language designed for printing from computer screens, especially from programs like Microsoft Windows. It's compressed to send information faster to the printer. It was once called PCL XL or PXL.
• PCL 6 Standard: This part is like PCL 5e or PCL 5c. It's included to make sure newer printers can still work with older PCL commands.
• Font synthesis: This part handles scalable fonts, manages fonts, and stores forms and fonts.

PCL 6 "Enhanced" was built in a way that makes it easier to update for future HP printers. It can print complex pictures faster and reduces how much information needs to be sent over a network. This means your computer gets back to you quicker after you hit print.

Sometimes, a product might say it's PCL 6 compatible but might not include the older PCL 5 features. PCL 6 Enhanced is mostly created by printer drivers in Windows and CUPS (Common Unix Printing System). Because of how it's built, most custom programs don't use it directly.

PCL 6 Class Revisions

PCL 6 has gone through several updates, called "classes," to add new features.

Class 1.1

• Drawing Tools: This class added support for drawing lines, circles, rectangles, and other shapes. It also handled images and allowed for special effects like clipping parts of an image.
• Color Handling: It supported different color options, including basic color palettes and grayscale.
• Compression: It could compress data using a method called RLE (run-length encoding) to make files smaller.
• Measurements: Printers could understand measurements in inches, millimeters, and tenths of millimeters.
• Paper Handling: This class allowed choosing different paper sizes like Letter or A4. You could also select paper from different trays or print on both sides (duplex).
• Fonts: It supported bitmap and TrueType fonts. You could rotate, scale, or stretch outline fonts.

Class 2.0

• Compression: Added support for JPEG image compression.
• Paper Handling: Allowed sending printed pages to different output bins. It also added more preset paper sizes like A6.
• Fonts: Text could be printed vertically.

Class 2.1

• Color Handling: Added a feature for matching colors more accurately.
• Compression: Added a compression method called Delta Row.
• Paper Handling: More paper sizes were added, like B5.

Class 2.2

• Compression: Added support for JFIF (JPEG File Interchange Format).

Class 3.0

• Color Handling: Allowed using different halftone settings for text, pictures, or graphics.
• Protocol: This class allowed PCL 5 features to be used within PCL 6 print jobs.
• Fonts: Supported PCL fonts.

PJL: Printer Job Language

PJL (Printer Job Language) was introduced with the HP LaserJet IIIsi printer. PJL adds controls for the entire print job. For example, it can switch between different printer languages, separate print jobs, and give feedback about the printer's status. It also helps manage files on the printer.

See also

In Spanish: Printer Command Language para niños

• CaPSL
• Encapsulated PostScript
• Foomatic
• Hewlett-Packard Raster Transfer Language (HP RTL)
• GNU Plotutils
• PostScript Printer Description
• Ghostscript