This is the well known image of the Bf109K-4 from the JG27 captured by the end of war in Czechoslovakia. Image is not very sharp, the copy I have, but there are definitely much of the details visible for the detail analyze.
It is very interesting to mention how many variation this plane have in various publication as well in the model releases, scale kits or decals. This variation range from the plane shown in the topside colors of RLM81 and RLM82 with the fuselage sides, bottom as well tail and wings bottom in the grey green color. Fuselage number with bars were often present in blue color. But also the same plane could be seen in various decals manufacturers give its own description of this plane and there is variation in the number and bar color, red in some cases, as well camouflage colors range with RLM75 and green on topside with some variants where is fuselage and bottom color grey green or standard RLM76. Confusion in the research and modelers world still live on.
Lets try to describe what is seen on the image above. Airplane on the image is the Messerschmitt Bf109K-4 manufactured or maybe better to say assembled, in Messerschmitt-Regensburg factory and belong to the aircraft series with number range 332XXX. Feature of this series that they have RLM75 and RLM 83 colors on topside with most of the side and bottom surfaces in the RLM 76 color. One section of the wing bottom remained in the natural metal.

Image above show some of the very interesting details which is very interesting. First at all take attention on the wings which is mostly camouflaged except of the control tabs and outer flaps. They are obvious in the much pale and uniform color but it is doubtful to precise determine what color that could be. So there could be camouflage light blue but also protective grey green. As well the wings are partially camouflaged, I decide to use grey green protective color but again to say, this can not be proof. Also note that there is also visible part of the flaps from the other wing and it is also in very pale color.
Another very interesting detail is the fuselage cross and it is not white at all but in the bottom color, RLM 76. This is more then obvious on the image where could be noted grey value of the cross color and grey value of the underside color and they are the same. If you compare it with white elements of the insignia in the close, you have clear proof that this cross color is not white at all. So situation is crystal clear there. Also cross lack of the bottom shapes and the shape consist of the green camouflage color only in the inner space of the cross. All presentation of this plane, no matter modeling or illustrations, presents it as white cross.
Vertical rudder is a little bit different then the rest of the bottom light color and maybe it is made in the grey green color. But this is very weak possibility and not possible to proof as well this section are close to the ground where is influence of the dust and dirt moderate so this difference could be also result in the different level of dirt so it is hard to claim proof of the another color then the standard RLM76. There could be noted difference in the covering with camouflage spots of the rudder and stabilizer so maybe the same rudder was replaced and new color could look different then the same one apply some before. On image is visible that fabric covering is missing as result of the souvenir collector of the time.
One more detail of interest is the canopy frame which is in very dark color and possible that the same color is the RLM 66 which is much used in the basic covering of this assembly section. And finally to note small input image in which show that spinner is whole in the black green color so no white spiral as noted many times before.
Reference publication [
Aero Journal]