Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Guillermo Luijk on January 16, 2021, 08:04:29 pm

Title: Photoshop curves to implement perceptually uniform colourmaps (VIRIDIS)
Post by: Guillermo Luijk on January 16, 2021, 08:04:29 pm

This is of no use to photographers but could interest those Photoshop users involved in data visualization. I have recreated through Photoshop curves (16-point ACV files), the complete VIRIDIS colourmap set, very familiar to R, Python and Matlab users: 'magma', 'inferno', 'plasma', 'viridis' and 'cividis' colourmaps.

These colour scales have the property to be perceptually uniform (designed on constant delta E increments) and strictly respect a conversion to grayscale (interesting for printing for instance).

The R code used to generate the ACV files and a TIFF containing those 5 curves can be found here: https://github.com/gluijk/photoshop-colourmaps

http://guillermoluijk.com/misc/photoshopcurves.png

These are the curves:
http://guillermoluijk.com/misc/photoshopcolourmaps.gif

Regards

Title: Re: Photoshop curves to implement perceptually uniform colourmaps (VIRIDIS)
Post by: Bart_van_der_Wolf on January 17, 2021, 02:12:08 pm

Quote from: Guillermo Luijk on January 16, 2021, 08:04:29 pm

This is of no use to photographers but could interest those Photoshop users involved in data visualization. I have recreated through Photoshop curves (16-point ACV files), the complete VIRIDIS colourmap set, very familiar to R, Python and Matlab users: 'magma', 'inferno', 'plasma', 'viridis' and 'cividis' colourmaps.

These colour scales have the property to be perceptually uniform (designed on constant delta E increments) and strictly respect a conversion to grayscale (interesting for printing for instance).

The R code used to generate the ACV files and a TIFF containing those 5 curves can be found here: https://github.com/gluijk/photoshop-colourmaps

http://guillermoluijk.com/misc/photoshopcurves.png

These are the curves:
http://guillermoluijk.com/misc/photoshopcolourmaps.gif

Well done. I've been using the VIRIDIS colormaps for my graphs/(heat)maps/etc. of my local Air Quality Measurement project. Very useful for such visualization applications.

Title: Re: Photoshop curves to implement perceptually uniform colourmaps (VIRIDIS)
Post by: Guillermo Luijk on January 19, 2021, 06:25:06 am

Very interesting Bart, are you publishing your results somewhere?

BTW I wrote a short article about the subject:

https://www.overfitting.net/2021/01/mapas-de-color-viridis-en-photoshop.html

Regards

Title: Re: Photoshop curves to implement perceptually uniform colourmaps (VIRIDIS)
Post by: Guillermo Luijk on January 19, 2021, 07:04:47 pm

For the same price I just added the curves for the five R built-in colourmaps: "rainbow", "heat.colors", "terrain.colors", "topo.colors", "cm.colors":

http://guillermoluijk.com/misc/photoshopcolourmapsrstd.png

Regards