Printer yellow dot tracking
Some printers are able to secretly track you, is yours on the list? iStock

When NSA contractor Reality Winner allegedly printed out a trove of top secret government information, little did she know that a hidden feature within the printer called tracking dots could forensically lead authorities straight back to her.

What you may not know is that most laser printers made today, found everywhere from offices to public libraries, all have the same tracking technology. So, is your printer able to track you?

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Below is a list of printer manufacturers the non-profit digital privacy organisation, EFF (Electronic Frontier Foundation), has put together to show which are using invisible yellow dot forensic technology to give away location, time, date, serial number and user ID every time they are used.

Major brands from Canon to Xerox all feature on the lengthy list.

List of known printers using yellow dot tracking

Brother

HL-2700CN

HL-4200CN

Canon

CLC 1000

CLC 2400

CLC 3002

CLC 4000

CLC 5000+

CLC-iR 3200-C1

Color imageRUNNER C2570

Color imageRUNNER C3100CN

Color imageRUNNER C3200

Color imageRUNNER C3200N

Color imageRUNNER C3220

Color Laser Copier 1150

Imageclass MF8170C

Dell

3000CN

3100CN

5100CN

Epson

AcuLaser C900

AcuLaser C1100

AcuLaser C1500

AcuLaser C1900

AcuLaser C3000

AcuLaser C4000

Fuji: see Xerox

Hewlett-Packard

Color LaserJET 1550L

Color LaserJET 1600

Color LaserJET 2500

Color LaserJET 2500L

Color LaserJET 2500N

Color LaserJET 2550

Color LaserJET 2550L

Color LaserJET 2550N

Color LaserJET 2600N

Color LaserJET 2680

Color LaserJET 2700N

Color LaserJET 2840

Color LaserJET 3500

Color LaserJET 3550

Color LaserJET 3600DN

Color LaserJET 3700

Color LaserJET 3700DN

Color LaserJET 3700N

Color LaserJET 4600

Color LaserJET 4600DN

Color LaserJET 4600HDN

Color LaserJET 4600N

Color LaserJET 4650

Color LaserJET 4650DN

Color LaserJET 4650DTN

Color LaserJET 4700

Color LaserJET 4700DN

Color LaserJET 4700DTN

Color LaserJET 5100CN

Color LaserJET 5500

Color LaserJET 5500ATN

Color LaserJET 5500DN

Color LaserJET 5500HDN

Color LaserJET 5550

Color LaserJET 5550DN

Color LaserJET 5550DTN

Color LaserJET 9500

Color LaserJET 9500HDN

Color LaserJET 9500MFP

IBM

Infoprint Color 1454 (unclear)*

Infoprint Color 1464 PS3

Konica

Bizhub C252

Bizhub C350

Colorforce 1501

Colorforce 8050

DialtaColor CF 2001 (unclear)*

DialtaColor CF 2002 (unclear)*

Ikon CPP500E

Magicolor 2200 DL

Magicolor 2210

Magicolor 2300 DL

Magicolor 2300 W

Magicolor 2350 yes

Magicolor 2350 EN

Magicolor 2400 W

Magicolor 2430 DL

Magicolor 2450

Magicolor 3100

Magicolor 3300

Magicolor 5450

Magicolor 7300

Kyocera

C2630D

FS-C5016N

FS-C5020N

FS-C5030N

FS-C8008

Mita KM-C2230

Lanier

LD238C

LP125CX/LP126CN

Lexmark

C510

C720

C752

C752N

C760

C910

C912

Minolta: see Konica

NRG

DSc38

Panasonic

Workio KXCL-500

Ricoh

Aficio 1224C

Aficio 1232C

Aficio CL 2000

Aficio CL 3000

Aficio CL 3000E

Aficio CL 6010

Aficio CL 7000

AP 206

Infotec/Danka ISC 2838

Savin

C3210

CLP35

Toshiba

eStudio 210c

eStudio 211c

eStudio 310c

eStudio 311c

eStudio 2100c

eStudio 3100c

eStudio 3511

FC15

FC15i

FC22

FC22i

FC25P

FC25Pi

FC70

Xerox

DocuColor 12

DocuColor 40

DocuColor 1521

DocuColor 1632

DocuColor 2000

DocuColor 2045

DocuColor 2240

DocuColor 3535

DocuColor 5252

DocuColor 6060

Phaser 790

Phaser 8400B (unclear)*

Phaser 8400DP (unclear)*

Phaser 8400DX (unclear)*

Phaser 8400N (unclear)*

Phaser 8440DP

WorkCentre M24

WorkCentre Pro (all models)

*EFF unsure if yellow dots are tracking, or unrelated artifacts due to printing technique

What are yellow tracking dots?

Some printers (as listed above) will secretly print a pattern of yellow dots in the background of any document a user prints off. These dots are invisible to the naked eye but when put under a microscope or blue light, they will appear. The unique pattern of dots are put through a deciphering tool to disclose information about where and when the document came from, but you wouldn't even know they were there.

The EFF claims "it is probably safest to assume that all modern colour laser printers do include some form of tracking information". Following an freedom of information request, the EFF was given a number of documents that suggested "all major manufacturers entered a secret agreement with governments to ensure that the output of those printers is forensically traceable".

Laser printer yellow dot code
Tables like this one are used to 'read' data represented by the yellow dots EFF

Its list of manufacturers using yellow dot tracking was created by looking at printed documents under blue light or microscope, printer manuals and manufacturer statements. It also included statements from technicians and sellers.

It states that documents printed on non-laser printers may not be subject to the same yellow dot tracking system but did not rule out other forms of hidden forensic tracking that it is currently unaware of.