Woodblock prints of the 19th century tend to be a bit anachronistic when depicting heroes of old.This is due partly because of artistic license and partly because 19th century artists had a little grasp of what a proper armour would look like when worn.They also followed the prevailing fashion which in the 19th century was for the resurrection of antique 12th -13th century armour(which would have been quite impractical for a 16th century warlord like Imagawa Yoshimoto).To all the above you can add the Tokugawa Bakufu's (military government) ban of representation of historical figures (for political reasons which would take a long time to explain).Having said all that,Imagawa Yoshimoto was head of an illustrious warrior house who met his end,tragically,at the battle of Okehazama(1560),the same battle that set the Japanese "Prince" (in the Machiavellian sense of the word) Oda Nobunaga on his way to glory.As such he could have worn an armour of an earlier style (like the one Nico Ableev gave him).Let me state right here that ,as so often the case,Nico(a fantastic artist) has done a grat job technically but little research and this work is full of inaccuracies and mistakes(I will stop here for this should be of no concern to anyone but to the most dedicated samurai fans and in no way should it distract you from having a lot of fun painting this miniature).When it comes to painting this,keep a few rules in mind.
In Japan almost all metal surfaces besides live blades were covered in multiple layers of "Urushi" which is not a lacquer but its visible effect is much the same.Urushi ( a tree sap with admixtures) tends to dry in dark brown-black glossy hues.It can be coloured but in a limited palette (dark red,gold)but for the style of armour worn by Yoshimoto,keep it black.
The multitude of laces visible (odoshi) which contrary to popular belief,were not there to hold the various sane (scales) and tare (lames) together (this was actually done by leather thongs beneath the odoshi and not visible) could take a bewildering array of colours from uniform bright red to multi-color variations.
Fabricks would tend to be expensive brocaded silks (or covered in silk) in the case of rich daimyo like Yoshimoto so you can feel free to experiment.
I could add a few reference books but if you are not into japanese arms and armour there is no reason for you to spend money on them.Pinterest could provide you with many photos of actual armours in museums as well as patterns for the odoshi and the fabrics.You can also look up David Thatcher on FB,one of the very few katsushi (armour maker) of non Japanese origins.He is a trasure trove of knowledge.Any publication with the name Ian Bottomley on the cover should also be unconditionably trusted.
Sorry for the lengthy post (hey,can't blame a junky for his addiction,right?).If you need any further info or wish to discuss on details,please feel free to PM me.
Oda.