# Problems with generating cpt palette files and ... odd problem after editing color palette files

**URL:** <https://forum.generic-mapping-tools.org/t/problems-with-generating-cpt-palette-files-and-odd-problem-after-editing-color-palette-files/1875>\
**Category:** Q&A\
**Created:** [July 8, 2021, 4:38pm UTC](https://forum.generic-mapping-tools.org/t/problems-with-generating-cpt-palette-files-and-odd-problem-after-editing-color-palette-files/1875 "2021-07-08T16:38:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![smauget](https://avatars.discourse-cdn.com/v4/letter/s/edb3f5/32.png) [@smauget](https://forum.generic-mapping-tools.org/u/smauget)\
**Post date:** [July 8, 2021, 4:38pm UTC](https://forum.generic-mapping-tools.org/t/problems-with-generating-cpt-palette-files-and-odd-problem-after-editing-color-palette-files/1875/1 "2021-07-08T16:38:35Z")

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OSX 10.14.6  
GMT Version = ? gmt --version gives me an error about a dylib not being loaded. Isuspect its really old though. The executables on my filesystem are from Nov 2012.

I’m having one relatively straightforward problem with generating cpt files.

When I enter::

makecpt -Cseis -T-600/600/50 \>& seis.cpt …the output looks fine

but …makecpt -Cpanoply -T-600/600/50 results in:

makecpt: GMT Fatal Error: Z slice with dz = 0

The other problem is a little more mysterious and may no be a GMT problem.

Occasionally I might edit a cpt file to replace one color with another. For instance, I might replace the yellow that occupies the region around 0.0 in the above seis.cpt file with white. A simple replacement of 255 255 0 with 255 255 255. When I input that file to psscale and plot the results in the Apple preview application it looks fine. But when I open the postscript file in Adobe Illustrator I get black sections across the color scale. Is this a GMT problem or an Adobe Illustrator problem?

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**Author:** ![pwessel](https://yyz1.discourse-cdn.com/flex047/user_avatar/forum.generic-mapping-tools.org/pwessel/32/30_2.png) [@pwessel](https://forum.generic-mapping-tools.org/u/pwessel)\
**Post date:** [July 11, 2021, 4:38am UTC](https://forum.generic-mapping-tools.org/t/problems-with-generating-cpt-palette-files-and-odd-problem-after-editing-color-palette-files/1875/2 "2021-07-11T04:38:22Z")

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Your panoply issue usually means you have a file called panoply.cpt in your current directory so it reads that instead but the file is empty. E.g.:

```
touch panoply.cpt
gmt makecpt -Cpanoply -T-600/600/50
makecpt [ERROR]: CPT panoply.cpt has no z-slices!

```

As for the Illustrator question: Usually means a bug - they have bugs every other version of Illustrator. Maybe you can work around it by making a PDF first before opening in AI.