The results from KrakatoaMX and Krakatoa for C4D are different with the same settings. Probalby a color mapping issue?
best mnu
The first thing to ensure is that the scenes are identical.
I tested here like this:
*In C4D with default scene scale of Centimeters I created a default Sphere with Radius 100cm and 24 segments.
*I created a PRT Volume from it and set Render Spacing to 1 cm and checked the Jitter option
*I placed a free camera at 0,0,-500 looking straight at the object
*I placed a Point light at -500,0,0 (to the left of the sphere)
*I rendered at 800x600 with all settings set to default, except for Final Pass Density Exponent set to -3
Then I repeated the same in Max:
*I set the Customize > Units Setup > System Units Setup to 1GU = 1 cm
*I created a Sphere at 0,0,0 with Radius of 100 and 24 segments (instead of the default 32)
*I made a PRT Volume from it (it defaults to 1 cm render spacing and jitter is on already)
*I created a Free Camera at 0,-500,0 looking straight at the front of the PRT Volume
*I set the Camera Focal Length to 36.0 to match the C4D camera (HFOV = 53.13)
*I created an Omni light at -500,0,0
*I rendered at 800x600 with default settings except fof the -3 Exponent.
I captured the C4D image viewer and pasted it in Gimp, then I pasted the 3ds Max image on top of it to create an animated GIF.
The only difference between the two render outputs is the random jitter because Max/KMX uses a different generator than Krakatoa SR:
So I would suggest you make sure you are using EXACTLY the same scene scale and exactly the same particle object.
Disabling the Linear Workflow in C4D is also something that people seem to suggest to ensure you see the original output of Krakatoa (in my 3ds Max, under Customize>Preferences, Gamma and LUT are disabled, too)