Hexatrigesimal file icon colors
Computer file icon sets are typically for only a limited number of filetypes which often exclude rare or unusual filetypes. By assigning a 3-digit hexatrigesimal (base-36) number to each filetype, 363 = 46656 unique file icons can be generated.
assigning triplets
Begin by assigning every file extension a three-character name. For most file extensions with more than three characters, the extension can simply be truncated to the first three characters. Otherwise, new three-character names will need to be assigned to conflating file extensions. For example: ".xls", ".xlsx", and ".xlsm" can be assigned as XLS, XLX, and XLM. One-letter and two-letter file extensions can be represented as three-letter file extensions by adding trailing zeros. For example: ".m" and ".7z" files assigned as M00 and 7Z0.
character mapping
Each character from 0 to Z can now be used to represent a hexatrigesimal number digit. Each hexatrigesimal digit from 0 to Z has to then be assigned an integer decimal (base-10) value from 0 to 255. This series of decimal integers from 0 to 255 are then converted to their corresponding values of 0 to FF in hexadecimal (base 16).
- View this table in Portable Document Format (
pdf). - View this table in LibreOffice Writer format (
odt). - View this table in Microsoft Office Word format (
docx).
| base-36 number | base-10 number | base-10 value | base-16 value |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 1 | 1 | 7 | 7 |
| 2 | 2 | 15 | F |
| 3 | 3 | 22 | 16 |
| 4 | 4 | 29 | 1D |
| 5 | 5 | 36 | 24 |
| 6 | 6 | 44 | 2C |
| 7 | 7 | 51 | 33 |
| 8 | 8 | 58 | 3A |
| 9 | 9 | 66 | 42 |
| A | 10 | 73 | 49 |
| B | 11 | 80 | 50 |
| C | 12 | 87 | 57 |
| D | 13 | 95 | 5F |
| E | 14 | 102 | 66 |
| F | 15 | 109 | 6D |
| G | 16 | 117 | 75 |
| H | 17 | 124 | 7C |
| I | 18 | 131 | 83 |
| J | 19 | 138 | 8A |
| K | 20 | 146 | 92 |
| L | 21 | 153 | 99 |
| M | 22 | 160 | A0 |
| N | 23 | 168 | A8 |
| O | 24 | 175 | AF |
| P | 25 | 182 | B6 |
| Q | 26 | 189 | BD |
| R | 27 | 197 | C5 |
| S | 28 | 204 | CC |
| T | 29 | 211 | D3 |
| U | 30 | 219 | DB |
| V | 31 | 226 | E2 |
| W | 32 | 233 | E9 |
| X | 33 | 240 | F0 |
| Y | 34 | 248 | F8 |
| Z | 35 | 255 | FF |
file extensions
Each file-extension character triplet corresponding to a 3-digit base-36 number between 000 and ZZZ now represents one of 363 = 46656 possible colors from #000000 to #ffffff.
- View this table in Portable Document Format.
- View this table in LibreOffice Calc format (
ods). - View this table in Microsoft Office Excel format (
xlsx).
| extension | triplet | hexcolor | color |
|---|---|---|---|
DefaultIcon
|
000 | #000000
|
|
7z
|
7Z0 | #33ff00
|
|
css
|
CSS | #57cccc
|
|
doc
|
DOC | #5faf57
|
|
docx
|
DOX | #5faff0
|
|
htm
|
HTM | #7cd3a0
|
|
ico
|
ICO | #8357af
|
|
jpg
|
JPG | #8ab675
|
|
mediawiki
|
MED | #a0665f
|
|
mht
|
MHT | #a07cd3
|
|
ods
|
ODS | #af5fcc
|
|
odt
|
ODT | #af5fd3
|
|
oxps
|
OXP | #aff0b6
|
|
pdf
|
#b65f6d
|
||
png
|
PNG | #b6a875
|
|
svg
|
SVG | #cce275
|
|
txt
|
TXT | #d3f0d3
|
|
xht
|
XHT | #f07cd3
|
|
xls
|
XLS | #f099cc
|
|
xlsx
|
XLX | #f099f0
|
|
xml
|
XML | #f0a099
|
|
xps
|
XPS | #f0b6cc
|
|
zip
|
ZIP | #ff83b6
|
|
^^DIRECTORY^^
|
ZZZ | #ffffff
|
SVG
A simple monochromatic icon can be created with Scalable Vector Graphics (SVG) Extensible Markup Language (XML). View icon examples.
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"> <svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="16" width="16"> <title>MEDIAWIKI (Wikimedia MediaWiki) icon</title> <rect height="16" width="16" fill="#a0665f" /> <!-- © (Copyright) 2026-04-13 Nicole Sharp Nicole Sharp’s Homepage: https://www.nicolesharp.net/ Content in this file is available under the Creative Commons Attribution-ShareAlike (CC BY-SA) 4.0 International Public License: https://www.nicolesharp.net/wiki/CC_BY-SA --> </svg>
HTACCESS
The new icons can now be implemented in ASF (Apache Software Foundation) Hypertext Protocol (HTTP) Server Access (HTACCESS) Index Options.
IndexOptions +FancyIndexing DefaultIcon /images/icons/filetypes/000.svg AddIcon /images/icons/filetypes/zzz.svg ^^DIRECTORY^^ AddIcon /images/icons/filetypes/7z0.svg .7z AddIcon /images/icons/filetypes/css.svg .css AddIcon /images/icons/filetypes/doc.svg .doc AddIcon /images/icons/filetypes/dox.svg .docx AddIcon /images/icons/filetypes/htm.svg .htm .html AddIcon /images/icons/filetypes/ico.svg .ico AddIcon /images/icons/filetypes/jpg.svg .jpg .jpeg AddIcon /images/icons/filetypes/med.svg .mediawiki AddIcon /images/icons/filetypes/mht.svg .mht .mhtml AddIcon /images/icons/filetypes/ods.svg .ods AddIcon /images/icons/filetypes/odt.svg .odt AddIcon /images/icons/filetypes/oxp.svg .oxps AddIcon /images/icons/filetypes/pdf.svg .pdf AddIcon /images/icons/filetypes/png.svg .png AddIcon /images/icons/filetypes/svg.svg .svg AddIcon /images/icons/filetypes/txt.svg .txt AddIcon /images/icons/filetypes/xht.svg .xht .xhtml AddIcon /images/icons/filetypes/xls.svg .xls AddIcon /images/icons/filetypes/xlx.svg .xlsx AddIcon /images/icons/filetypes/xml.svg .xml AddIcon /images/icons/filetypes/xps.svg .xps AddIcon /images/icons/filetypes/zip.svg .zip IndexOptions +IconsAreLinks # https://httpd.apache.org/docs/current/mod/mod_autoindex.html
problems
There are still a couple of problems here. The first is that most file extensions do not contain decimal number characters so about ten thousand or thirty percent (~10/36) of available colors are under-utilized. An attempt to solve this can be by contracting the hexatrigesimal (base-36) color space from 036 to Z36 to a hexavigesimal (base-26) color space from A26 to Z26. This results in 263 = 17576 possible colors. But even eliminating 29080 extraneous colors does not help to significantly resolve the second problem in that consecutive colors such as for ".ods" versus ".odt" are extremely difficult to practically impossible to distinguish visually. Even if the human viewer cannot tell the difference though, the assigned colors are still mathematically unique which provides a second semantic signal to indexing bots in addition to the file extension. For practical usage by humans, consecutive file extensions are often for the same application. For example: both ".ods" and ".odt" are for LibreOffice so this still provides a useful semantic cue for the human viewer (as intended) even if these two individual colors cannot be differentiated visually. There may exist other extension pairs though that could be visually conflated but this problem exists with a traditional icon set as well in that with limited icons available, multiple file extensions have to be assigned the same icon.