Fyris Alpha - ZLS Colour Tables

ZLS Colour Tables

The ZLS System used text file based colour tables. The colour tables are written in unecrypted text format in .ctab files. The complete set of tables including this file are available as a single download.

Each file has a simple header indicating the exact variation of the format, and the number of colours in the table, followed by the colour indices and RGB values (or index + single grayscale values for simple gray tables).

There are three basic formats, indicated by the first line of the ctab file:

0: Decimal values used, i.e. 0-255, or 0-65535
1: Hexadecimal values used: ie 00 - FF or 0000 - FFFF
2: Floating point values: 0.0 - 1.0

The next line indicates the number of bits per value. It an be 8 or 16 for Decimal and Hexadecimal formats, and 16 for floating point format.

The next line indicates the number of colour components, 1 (grayscale) o 3 (RGB) then the number of colours follows, and is usually 256.

Finally the indices and values follow, 1 entry per line. For grayscale there are two columns, index then value, and for RGB there are 4 columns, index and red, green, blue values.

Format Examples:

13.ps.ctab:	0.1.rss.ctab:	31.123.ctab:	0.2.gray.ctab:
1 8 3 256 0 00 00 7f 1 00 00 83 2 00 00 87 3 00 00 8b …	1 16 3 256 0 ffff ffff ffff 1 fefe fefe f7bd 2 fdfd fdfd ef7b 3 fcfc fcfc e739 …	0 8 3 256 0 0 0 0 1 0 0 0 2 95 0 114 3 98 0 112 …	1 8 1 256 0 ff 1 fe 2 fd 3 fc …
Hex 8 bit Values, RGB	Hex 16 bit Values, RGB	Decimal 8 bit Values, RGB	Hex 8 bit Values, Grayscale

Download Code for reading Colour Table Files and writing 8 bit TIFFs

Colour Tables Preview

ctabs/01.rss	ctabs/02.gray	ctabs/03.gray_inverse

ctabs/04.grey_mod	ctabs/08.blue	ctabs/09.green

ctabs/10.red	ctabs/11.blackbody	ctabs/12.idlstd

ctabs/13.ps	ctabs/14.stern2	ctabs/15.ag1

ctabs/16.ag2	ctabs/17.ag3	ctabs/18.bluegold

ctabs/19.goldblue	ctabs/20.r1	ctabs/21.r2

ctabs/22.r3	ctabs/23.r4	ctabs/24.p1

ctabs/25.p2	ctabs/26.p3	ctabs/27.tim

ctabs/28.air	ctabs/29.water	ctabs/30.earth

ctabs/31.123	ctabs/32.barb	ctabs/33.barb2

ctabs/34.blob1	ctabs/35.blob2	ctabs/36.carl

ctabs/37.contour	ctabs/38.lograinbow	ctabs/39.subdued

	ctabs/40.bbwy

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