Warning

(Added 2015) Some of the documents that we previously received through FOIA suggested that all major manufacturers of color laser printers entered a secret agreement with governments to ensure that the output of those printers is forensically traceable. Although we still don't know if this is correct, or how subsequent generations of forensic tracking technologies might work, it is probably safest to assume that all modern color laser printers do include some form of tracking information that associates documents with the printer's serial number. (If any manufacturer wishes to go on record with a statement to the contrary, we'll be happy to publish that here.)

(Added 2017) REMINDER: IT APPEARS LIKELY THAT ALL RECENT COMMERCIAL COLOR LASER PRINTERS PRINT SOME KIND OF FORENSIC TRACKING CODES, NOT NECESSARILY USING YELLOW DOTS. THIS IS TRUE WHETHER OR NOT THOSE CODES ARE VISIBLE TO THE EYE AND WHETHER OR NOT THE PRINTER MODELS ARE LISTED HERE. THIS ALSO INCLUDES THE PRINTERS THAT ARE LISTED HERE AS NOT PRODUCING YELLOW DOTS.

This list is no longer being updated.

Forensic investigations of the source of documents produced with other printing technologies are also possible, but, as far as we know, printers other than color laser and similar technologies do not deliberately encode their serial numbers in their output.

Introduction

This is a list of color laser printer models that do or do not print yellow tracking dots on their output.

We tried to interpret the information conveyed by these dots as part of our Machine Identification Code Technology Project.

Limitations of this information

A "no" simply means that we couldn't see yellow dots; it does not prove that there is no forensic watermarking present. (For example, the HP Color LaserJET 8500 series does not include any yellow tracking dots that we can see, but it may still include some kind of forensic marking, since the majority of other Color LaserJET models do. Other forensic marking techniques have been invented, and we do not yet know how to determine whether these techniques are used by a particular printer.)

A "yes" simply means that we (or another source, as noted) saw yellow dots that appeared anomalous to us. Until we decipher the marking schemes or receive other confirmation, this does not constitute proof that any particular kind of information is represented by these dots. In a very few cases, for example, they might be the result of a dithering technique, rather than a forensic mark, or they could be the result of a poorly calibrated printer. In most cases, we are confident that the arrangement of dots is intentional and is intended to track users.

Sources of information

We have employed three sources of information. We looked at printer output under a blue light and/or a computer microscope; we consulted press reports about printers (e.g. at Druckerchannel); we relied on printer manuals and other manufacturer statements. We welcome additional statements by manufacturers, resellers, or technicians.

Thanks to our friends at software firms and symphonies, public schools and physics labs, semiconductor fabs and ice cream parlors, in about a dozen countries around the world.

Table of printers

Manufacturer Model Dots? Comments
Brother
HL-2700CN yes volunteer test
HL-4200CN yes EFF test
Canon
CLC 1000 yes EFF
test
CLC 2400 yes EFF
test
CLC 3002 yes EFF
test
CLC 4000 yes EFF
test
CLC 5000+ yes EFF test
CLC-iR 3200-C1 yes EFF test
Color imageRUNNER C2570 yes EFF test
Color imageRUNNER C3100CN yes EFF test
Color imageRUNNER C3200 yes EFF test
Color imageRUNNER C3200N yes EFF test
Color imageRUNNER C3220 yes EFF test
Color Laser Copier 1150 yes EFF test
Imageclass MF8170C yes EFF test
LBP 2410 unclear faint dots; could be artifacts
Dell
3000CN yes EFF
test
3100CN yes EFF
test
5100CN yes EFF
test
Epson
AcuLaser C900 yes EFF test
AcuLaser C1100 yes EFF test
AcuLaser C1500 yes EFF test
AcuLaser C1900 yes EFF test
AcuLaser C3000 yes EFF test
AcuLaser C4000 yes EFF test
Fuji: see Xerox
Hewlett-Packard
Color LaserJET 1550L yes EFF test
Color LaserJET 1600 yes EFF test
Color LaserJET 2250LN no
(??)
EFF test
Color LaserJET 2500 yes EFF test
Color LaserJET 2500L yes EFF test
Color LaserJET 2500N yes EFF test
Color LaserJET 2550 yes EFF test
Color LaserJET 2550L yes EFF test
Color LaserJET 2550N yes EFF test
Color LaserJET 2600N yes EFF test
Color LaserJET 2680 yes EFF test
Color LaserJET 2700N yes volunteer test
Color LaserJET 2840 yes EFF test
Color LaserJET 3500 yes EFF test
Color LaserJET 3550 yes EFF test
Color LaserJET 3600DN yes EFF test
Color LaserJET 3700 yes EFF test
Color LaserJET 3700DN yes EFF test
Color LaserJET 3700N yes EFF test
Color LaserJET 4500 no EFF test
Color LaserJET 4500DN no EFF test
Color LaserJET 4500N no EFF test
Color LaserJET 4550 no EFF test
Color LaserJET 4550N no EFF test
Color LaserJET 4600 yes EFF test
Color LaserJET 4600DN yes EFF test
Color LaserJET 4600HDN yes EFF test
Color LaserJET 4600N yes EFF test
Color LaserJET 4650 yes EFF test
Color LaserJET 4650DN yes EFF test
Color LaserJET 4650DTN yes EFF test
Color LaserJET 4700 yes volunteer test
Color LaserJET 4700DN yes volunteer test
Color LaserJET 4700DTN yes volunteer test
Color LaserJET 5M no EFF test
Color LaserJET 5100CN yes EFF test
Color LaserJET 5500 yes EFF test
Color LaserJET 5500ATN yes EFF test
Color LaserJET 5500DN yes EFF test
Color LaserJET 5500HDN yes EFF test
Color LaserJET 5550 yes EFF test
Color LaserJET 5550DN yes EFF test
Color LaserJET 5550DTN yes EFF test
Color LaserJET 8500 no EFF test
Color LaserJET 8500DN no EFF test
Color LaserJET 8550 no EFF test
Color LaserJET 8550DN no EFF test
Color LaserJET 8550GN no EFF test
Color LaserJET 9500 yes EFF test
Color LaserJET 9500HDN yes EFF test
Color LaserJET 9500MFP yes EFF test
IBM
Infoprint Color 1454 unclear dithering?
Infoprint Color 1464 PS3 yes dithering?
Konica
   (Konica/Minolta)
Bizhub C252 yes EFF test
Bizhub C350 yes EFF test
Colorforce 1501 yes EFF test
Colorforce 8050 yes EFF test
DialtaColor CF 2001 unclear dithering?
DialtaColor CF 2002 unclear dithering?
Ikon CPP500E yes EFF test
Magicolor 2 Desklaser no EFF test
Magicolor 2200 DL yes EFF test
Magicolor 2210 yes EFF test
Magicolor 2300 DL yes EFF test
Magicolor 2300 W yes EFF test
Magicolor 2350 yes EFF test
Magicolor 2350 EN yes EFF test
Magicolor 2400 W yes EFF test
Magicolor 2430 DL yes EFF test
Magicolor 2450 yes EFF test
Magicolor 3100 yes EFF test
Magicolor 3300 yes EFF test
Magicolor 5450 yes EFF test
Magicolor 7300 yes EFF test
Kyocera
C2630D yes EFF test
FS-C5016N yes EFF test
FS-C5020N yes EFF test
FS-C5030N yes EFF test
FS-C8008 yes EFF
test
Mita KM-C2230 yes EFF test
Lanier
LD238C yes EFF
test
LP125CX/LP126CN yes EFF test
Lexmark
C510 yes EFF
test
C720 unclear retest
C752 yes EFF
test
C752N yes EFF
test
C760 yes EFF
test
C910 yes EFF
test
C912 yes EFF
test
Minolta:
see
Konica
NRG
DSc38 yes EFF
test
OkiDATA
    (Oki)
C5100 no EFF
test
C5150 no EFF
test
C5150N no EFF
test
C5200 no EFF
test
C5300 no EFF
test
C7200 no EFF
test
C7350 no EFF
test
C7400 no EFF
test
C7400N no EFF
test
C9200 no EFF
test
C9300 no EFF
test
C9400 no EFF
test
MIP C5540 no EFF
test
OkiLAN 8100E no EFF test
Panasonic
Workio KXCL-500 yes EFF test
Ricoh
    (see also Savin)
Aficio 1224C yes EFF test
Aficio 1232C yes EFF test
Aficio CL 2000 yes press report
Aficio CL 3000 yes EFF test
Aficio CL 3000E yes EFF test
Aficio CL 6010 yes EFF test
Aficio CL 7000 yes EFF test
AP 206 yes EFF
test
Infotec/Danka ISC 2838 yes EFF test
Samsung
CLP-500 no EFF
test
CLP-510 no EFF
test
CLP-550 no EFF
test
CLP-550N no EFF
test
Savin
C3210 yes EFF
test
CLP35 yes EFF
test
Tektronix:
see
Xerox
Toshiba
eStudio 210c yes mfr. statement
eStudio 211c yes mfr. statement
eStudio 310c yes mfr. statement
eStudio 311c yes mfr. statement
eStudio 2100c yes mfr. statement
eStudio 3100c yes mfr. statement
eStudio 3511 yes EFF test
FC15 yes mfr. statement
FC15i yes mfr. statement
FC22 yes mfr. statement
FC22i yes mfr. statement
FC25P yes mfr. statement
FC25Pi yes mfr. statement
FC70 yes mfr. statement
Xerox
  (Tektronix)
DocuColor 12 yes EFF test
DocuColor 40 yes EFF test
DocuColor 1521 yes EFF test
DocuColor 1632 yes EFF test
DocuColor 2000 yes mfr. statement
DocuColor 2045 yes EFF test
DocuColor 2240 yes EFF test
DocuColor 3535 yes EFF test
DocuColor 5252 yes EFF test/mfr. statement
DocuColor 6060 yes EFF test/mfr. statement
Phaser 560 no EFF test
Phaser 740 no EFF test
Phaser 750 (Z750V) no EFF test
Phaser 750P no EFF test
Phaser 790 yes EFF test
Phaser 850DP no EFF test
Phaser 860DP no EFF test
Phaser 1235 no EFF test
Phaser 6100 no EFF test
Phaser 6200 no EFF test
Phaser 6200DP no EFF test
Phaser 6250DP no EFF test
Phaser 6350DP no EFF test
Phaser 7300DN no EFF test
Phaser 7300DT no EFF test
Phaser 7700 no EFF test
Phaser 7750DN no EFF test
Phaser 8200DP no EFF test
Phaser 8200DX no EFF test
Phaser 8400 no dithering?
Phaser 8400B unclear dithering?
Phaser 8400DP unclear dithering?
Phaser 8400DX unclear dithering?
Phaser 8400N unclear dithering?
Phaser 8440DP unclear dithering?
Phaser 8550 no EFF test
Phaser 8550DP no EFF test
Phaser 8560MFP/D no EFF test
WorkCentre M24 yes EFF test
WorkCentre Pro (all
models)
yes mfr. statement