I've decided to eventually get around to making 1:1 colour schemes for all of the Tyranid Warrior art works of the 9 main Hive Fleets. Kronos is to be the first as it was the Hive Fleet I played during 9th Ed (that, and I am thoroughly biased for it haha). 
For Kronos, the model used is a Norn Emissary as it is what I had at hand. I will eventually post a combined recipe for all 9 Hive Fleets, with the examples being 9 Tyranid Warriors, built (possibly cut up / kitbashed if necessary) and posed to be as close to the art as possible. Said combined post will also include Neuroloids to serve as examples for brain matter for each Hive Fleet, as close to the style each artwork was made with so to stay true to it.
The next 1:1 will be Jormungandr, followed by Behemoth, Kraken, Ouroboros, Hydra, Leviathan, Tiamat, and Gorgon in this order.
To keep things as simple to follow / do yourself, all paints used will be from Citadel, except for white. (Citadel white sucks, use literally any other brand) 
Each ratio and mix has been tested multiple times, and is made to be exactly as shown in the art, so each ratio mentioned will be extremely specific.
If anyone has any questions or requests for artwork 1:1 recipes, feel free to ask me through Discord, located in my profile.
  Carapace (Body)
- Prime with   Chaos Black .
 - Drybrush heavily with   Dryad Bark  for smaller infantry, and   Rhinox Hide  for monsters. Do so only on the main body, i.e. neck, chest / upper torso, waist, and the base of the tail. 
 - Drybrush with   Stormvermin Fur  to a medium extent. On areas like the neck, waist and any other parts that would be less armoured or considered squishy, add a light drybrush of   Mephiston Red  over the   Stormvermin Fur .
 - Paint the heat sinks (the open vents on spore chimneys and limbs) with   Bugman's Glow , then with   Carroburg Crimson  thinned to a quarter ratio, 1 part CC, 3 parts water.   Lahmian Medium  can be used alternatively for this if you wish, however I do not recommend it nor do I have a ratio for it as I don't own any Citadel mediums due to my dislike of them.
 
Chitin (Everywhere but the Head)
- Paint the Chitin with a 1:1 mix of   Khorne Red  and   Mephiston Red .
 - Apply a shade mix of 2 parts   Nuln Oil , 1 part   Agrax Earthshade , 1.75 (1_3/4) parts water, and 0.25 (1/4)   Abaddon Black   to the recesses of the chitin.
 - Gently drybrush the carapace with   Mephiston Red  consistently until you have full coverage. You should be at a point where it gives an effect similar to both dusting it with an airbrush to add an all aspect light sourced and a heavier drybrush, just without filling any shaded areas.
 - Continue to drybrush with   Mephiston Red , but this time slowly add   Wild Rider Red  into the   Mephiston Red  until you are only using   Wild Rider Red , brushing lighter and softer with each layer. This will build a gradient once again similar to airbrushing, but you get to keep those shaded areas.
 
Chitin (Head)
- Paint the Chitin with a 1:1 mix of   Khorne Red  and   Mephiston Red .
 - Apply a shade mix of 2 parts   Nuln Oil , 1 part   Agrax Earthshade , 1.75 (1_3/4) parts water, and 0.25 (1/4)   Abaddon Black   to the recesses of the chitin.
 - Gently drybrush the carapace with   Mephiston Red , then with 2 parts   Mephiston Red  and 1 part   Wild Rider Red .
 - Feather the chitin on the head with 1:1   Celestra Grey  and   Dawnstone , heavier towards the front.
 - Drybrush the front and second plate of the chitin with   Dawnstone , lightly on the front and only the most raised areas on the second.
 
Tertiary Colour for Weapons Claws and Hooves
- Paint claws, hooves, and weapons with   Stegadon Scale Green , darkened with a dot of   Abaddon Black  mixed in. After a solid colour is achieved, glaze with just   Stegadon Scale Green  to bring out as much of the often scarce details on these areas as you can.
 - Drybrush hooves with   Fenrisian Grey .
 - Scything talons, rending claws and other such pointy things that may be present all get a dry highlight of   Fenrisian Grey . Similar to dry brushing in application, simply drag the brush over just an edge. You will need both less paint on the brush and to be a great deal softer than normal for this. 
 - Continue until each dry highlight is of a similar appearance to a chunky highlight, then do a crisp highlight of   Blue Horror , starting at the tip and stopping halfway up. Selectively highlight the same area with a 1:1 mix of literally any white that isn't from citadel and   Blue Horror .
 - For boneswords, give every sharp edge and raised detail a thin, crisp highlight of   Fenrisian Grey , and selectively highlight these with   Blue Horror  
 - Ranged weapons, such as the venom cannon in the art, get a combination of the two, starting with slightly uneven, staggered highlights towards the rear, slowly transitioning into a drybrush at the tip.
 - Vents and cords on ranged weapons are all done with the same coating of   Bugman's Glow  and   Carroburg Crimson  as those on the body.
 
Head and Face
- Drybrush the face and back of the head heavily with   Stormvermin Fur .
 - For the tongue, once again use   Bugman's Glow  and   Carroburg Crimson .
 - The teeth and eyes are painted with   Celestra Grey .
 
Encephalitic Tissue (Brains) 
There are two options I have found that work with the colours of Hive Fleet Kronos. I am still deciding on which works better then the other, and on top of this, both methods are unfinished, and will be updated as soon as it is finalised.
Method 1 (Green-Blue)
- Thin 1 part   Sotek Green  to 2 parts water. This will help reach all the folds and recesses. Repeat when each layer dries until colour is solid and the brain is fully covered.
 - Thin   Lothern Blue  to the same ratio, and then apply one layer only into the recesses of the brain
 - Alternately, instead of   Lothern Blue , use 1 part   Aeldari Emerald  thinned with 2 parts water and glaze the brain for a darker, more sea-green type finish
 
Method 2 (Pale Orange)
- Thin 1 part   Flayed One Flesh  with 1 part water. Coat the brain until you achieve a solid colour.
 - Thin 1 part   Wild Rider Red  with 4 parts water. Glaze the brain twice over with two separate coats so that it has even coverage. This should tint the brain slightly orange.
 
         
        
        
          
  
  
    
      Any questions regarding a published recipe or have any requests for one? Reach me on Discord @_ieatmarmalade_#4822