The Porcelain Jungle

By Sergio Barro

These are the "Post It" slides which answer the questions on the front page, please remember that the idea was to address each and every subject in one single and hopefully easy to remember slide. Should you need further explanations or more detailed info, feel free to e-mail me I'll be happy to try to help.

If imagaes are difficult to see, simply click on it and you will be taken to another page to see the picture in a bigger and more clear state. 

How Come There Are Digital Porcelain Tiles Ranked UGL (UNGLAZED) And GL (GLAZED)?

GL (Glazed) 

1) Porcelain body is normally neutral & lesser quality 
2) Engobe is a ceramic "prime" 
3) Digital printing depends on: "resolution" (D.P.I.) 
                                              Graphic Variation
                                              Same or multisize drops ETC. 
4) Glaze is normally for residential applications

Abration Test
UNI EN ISO 10545/7


UGL (Unglazed) 

1) Porcelain body is normally color body & of higher quality
2) Lack of engobe requires higher qality decoration
3) Digital printing depends on: "Resolution" (D.P.I.)
                                              Graphic Variation
                                              Same or multisize drops ETC. 
4) Glaze is for commercial & residential applications 

Abrasion Test
Deep abrasion test
UNI EN ISO 10545/6

All Digital Polished Porcelain Fall In GL Cathegory 

Are All Digital Polished Porcelain Treated/Nanotechnology Sealed? Why Do They Perform Differently?

Value Porcelains

1) Lower quality glass/glaze
2) Higher surface porosity
3) Organic sealer/nanoimpregnator 
  • Wear easily 
  • Discolors (when damaged & in contact with sunlight)
  • Less expensive impregnator 
4) Higher optical haze effect 
5) can hide shadowing effect 
6) Softer surface, very difficult to fix scratches with proper tools


Premium Porcelains

1) Higher quality glass/glaze 
2) Lower surface porosity
3) Inorganic sealer/nanoimpregnator
  • Does Not wear easily 
  • Does Not discolor (turning yellow) 
  • More expensive impregnator
4) Dramatic reduction of optical haze 
5) No shadowing effect 
6) With proper tools/kits/products, some scratches can be fixed

All Digital Polished Porcelain Are Sealed And Scratch

D.C.O.F....What To Look For? (Please Check ANSI 326.3 New Product Use Classification Page).
Ex-ANSI 137.1

DIN 51130 & 51097

BS EN 13036

Minimum Requairment Indor Flat Surface 
0,42 or above 

Minimum Requirement Indoor Flat Surface
R9 (R11 if wet)

Minimum Requirement Indoor Flat Surface
It depends. 
A very clear chart explains each given situation from PTV 12 to PTV 35

Min. Req. Outdoor App.
Test does not specify. 
Not reliable

Min. Req. Outdoor App.
R11 -> DIN 51130
If a pooldeck A+B is required DIN 51097 
(Bare foot test) 

Min. Req. Outdoor App. 
PTV 45 (Hard rubber/shoes) 
PTV 40 (Soft rubber/bare foot)
Again pls. check chart

  • Lower than 0,42 indoor use is admitted if measures are in place to keep floor dry
  • No guidance for indoor wet areas, ramps ETC.

  • Indoor dry R9
  • Indoor transitional R10
  • Indoor wet or outdoor R11 (A+B)
  • R12, R13 pls. see test

  • The most accurate test
  • Can test on jobsite 
  • Very specific which value to use in every situation
  • C.T.I.O.A aslo adopts it


A.N.S.I. 3263 Does Not Give Guidelines...Barely Some Numbers...

Abrasion Test, P.E.I. vs Deep Abrasion & MOHS Scale?

UNI EN ISO 10545/6

EN 101
(Scratch Test)

GL: Glazed Tiles

UGL: Unglazed Tiles

Was Carried On 

  • P.E.I.   0 Abrasion under 100 rev. 
  • P.E.I.   I/1  "150"
  • P.E.I.   II/2    "600"
  • P.E.I.   III/3  "BTW 750-1500"
  • P.E.I.   IV/4  "2100-5000-12000"
  • P.E.I.   V/5  ">12000+cleaning test"

  • Rotating Disc
  • 150 Rotations
  • Abrasive Material
1) For a Tile To Pass, Must Release Less Than 
175 mm^3 of Material

1. Talc    
2. Gypsum    
3. Calcite    
4. Flourspar   
5. Apatite       
6. Feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond

This Test is NOT in The New ISO
NORMS Requirements And It Has NOT Been Replaced

P.E.I. 0-Wall tile only 
P.E.I. 1-Resid. ensuite bathrooms
P.E.I. 2 & 3-Light residential, little dirt, soft shoes
P.E.I. 4-Residential, light commerial, little dirt
P.E.I. 5-Residential & commercial

Commercial & Residential 
Use Tiles

As A Rule Of Thumb: 
MOHS 5 is the very Minimum for an ensuite bathroom floor
MOHS 6 is residential use 
MOHS 7 & above also commercial 

MOHS Test Was Considered Unreliable Beacause Of Its Manuality

Why Some Digital Porcelains Are "Deeper & More Realistic...?"
Value Porcelains

1) Lower definition (D.P.I.) < 360
A) Dots per inch= "pixles" 
2) Lower number of graphics ("faces")
A) Exp: on a 30"x60" Appr. 2
3) Partial color/tile saturation
A) Less pigments, "washed out" look
4) Partial print on tile surface 
A) Exp: On white marble look with dark vein, print is mainly on view (2 deffect) 

The lack of inbetween fine print, makes the tile look shallow but keeps background color

5) Binary printing
A) One size drops
B) Exp. 360 D.P.I. 
"Pixelized Effect"

6) May have "banding effect"
7) Mainly printed with 4 inks

Premium Porcelains 

1) Higher definition (D.P.I.) >360
A) Dots per inch= "pixles"
2) Higher number of graphics ("faces")
A) Exp: on a 30"x60" Apprx. 12 or more
3) Full color/tile saturation 
A) More pigments to avoid "washed out" look
4) Full print on all tile surface
A) Exp: On white marble look with dark vein, print/decoration must be on the vein as well as on the white (3 defect) 

The finer the print, the less background color change

5) Greyscale printing 
A) Multisize drops
B) Exp. 360 D.P.I. 
"Saturated Effect" 

6) No "banding effect" 
7) Printing with >4 inks

Grout Haze, Stains, Porosity...Solutions?
Grout Haze

  • N1 cause of all digital porcelain cleanability issues
  • It creates a film on top of the glaze which traps all drit 
  • Almost impossible to see on light colored tiles & tone to tone grout
  • Glaze is a "permanent sealer" and protects from stains

  • Acid base solutions
  • Specific Gro. Haz. removal products like fila deterdek 
  • If Epoxy grout (acid proof) must use epoxy grout removers
  • If this inorganic dirt film has trapped organic dirt/grease, food, etc. an alkaline solution must be used first to remove this organic dirt, then rinse the floor, apply the acid/proper grout haze removal to lift the inorganic dirt/film, rinse floor.
  • Shop Vac/liquid Vacuums & abrasive pads scrubbers work best in these processes


  • Each stain has its "Kriptonite"
  • No need for acid to clean grease or solvents to clean lime/calcar

Solvents Acetone, benzene paint strippers, etc. 
  • Glue based stains
  • Rubber marks
  • Ink, permanent marckers
  • Tar & Nail varnish
  • Waes & resins
  • Etc.

Alkaline, Bleach, sodium hyroxyde, etc. 
  • Coffee, beer, wine
  • Blood
  • Cola, Sodas
  • Nicotine
  • Grease, oil, etc
  • "Hot water huge help"

Acids, muriatic acid, hydrochloric acid
  • Cement, grout, etc. 
  • Rust, cigarette
  • Lime, calcar

Multi purpose cleaners like Barkepper friend & Magic eraser, are also very effective where solvents & alkaline are needed. 


  • Natural stone presnts large prorsity & cravises that need to be scaled repetedly overtime 

  • All digital matte porcelains do not have open porosity and cannot absorbe stains. Glaze protects surface & helps mainten.
  • If glaze is of poor quality and wears over time/traffic, then microporosity gets exposed and tile surface starts absorbing dirt & stains. 

  • All digital polished porcelains have a protective sealer./norm sealer is longer lasting/reliable
  • All polished technical porcelains (Full body, soluble salts, double loaded) are also sealed with sealers
  • All matte technical porcelains (full body, solub. salts, double loaded) are also receiving a layer of transparent glaze to close porosity, ease maintenance and avoid surface absorption. 

Digital Decoration Tech. Vs Traditional Dec. Tech...?
Traditional Decoration

  1. Silk screen, roll print, rotocolor must have contact with tile to decorate
  2. Definition apprx. 80 D.P.I. 
  3. Graphic variation max 4 3/4ft.
  4. Cannot decorate shallow end of the tiles, distressed edges, groves, pits, etc.

A) Note lack of color (white) along edges of the tiles creating "picture frame effect"
B) Note same lack of color (white) in shallow end of the structure/cleft
C) Note brown color on top of structure only
D) Note brushstroke low definition graphic
E) note lack of graphic variation
F) Note lack of natural shade/color variation, making it obvious, this is a tile (ceramic or porcelain) 

Digital Decoration

  1. Digital printers do not touch the tiles
  2. Definition from 180 to over 400 D.P.I.
  3. Graphic variation over 30ft
  4. Can decorate all parts of the tile

A) No "picture frame effect"
B) Full decoration/saturation in the shallow ends raised structure, clefting, edges, etc. 
C) Realistic multicolor effect
D) High definition (greyscale mode) graphic
E) Multigraphic/faces effect
F) Once installed, very, very similar to natural slate...without the "headaches" ...

Deep, Bright, Full of Matter/Glaze Colors (Esp. Reds, Yellows, Blues, Greens, Etc.) We See In Wall Tiles, Cannot Be Achieved Through Digital Technology. These Are Traditionally Decorted Tiles...At Their Best. 

Optical Hazing, Shadowing, Sealer Marks...?
How Many Faces? How Many D.P.I. ... What Are...
Warpage, Lippage, Grout Joints, Leveling Systems
  1. Majority of lippage is caused by attempting to compensate uneven substrate with imporper use of thinset. 
  2. ANSI A108.19: Must get substrate flatnes within tolerance before beginning installation & get paid for preperation costs.
  3. All tiles are warped to some degree due to firing process shrinkage.

ANSI A108.024.3.7 Acceptable Lippage Guidleines 
Gauged tiles= thin tiles= exTPT (thin porcelain tiles)
GPT< 36"x36"= 1mx1m
GPTP> 36°x36°= 1mx1m
Gauged Wall 3.5mm-4.9mm/ Gauged floor 5mm-6.5mm

ANSI A137.1 Allowable Warpage of Different Tiles
"Inherent Warpage"
Calibrated= sorted to meet manufact. caliber range
Rectified= All edges mecanically finished

4. Exp: 1/16" grout joint (2mm apprx) Allows 1/32" (1mm apprx) lippage + 12"x24" rect. (30mx60m) Allows another 1/32"(1mm) warpage. Total lippage+warpage: apprx 1/16"= 2mm with some exceptions
5. ANSI A108.024.3.8 grout joints rectif. tiles> 15"= minimum 1/8" (apprx. 3mm) & 3/16" (4.5mm apprx) For calibrated tiles> 15" Plus warpage of the longest edge should be 1/8"+ 1/32"= 5/32" (apprx. 4mm)
6. Never should the grout joint be less than 1/16" (apprx. 2mm)...
7. For offset intallation with tiles> 18"(45mm) maximum of 33% staggering is allowed
8. NTCA "critical lighting effect" Exp. at least 12" from the wall (lippage perception) also natural light through windows & doors at some angles 
9. Highly polished/reflecting tiles can trigger lippage perception

Leveling Systems With Skilled Workmanship Will Help Reduce Lippage & Grout Joints Especially In Large formats