In principle a thin film with a printed image on one side and water soluable glue on the other. How well decals adhere to the surface depends on flexibility of the film, quality and age of the glue and last not least texture of the surface to which the decal is to be applied. - And here the problems begin. Non specular paint is rough like a field of pebbles. The decal film lies on top of each pebble and therefore there are a lot of gaps where the glue doesn't stick. The result is not a painted-on appearance but something with a silvery surround. Decal softeners help a little, but not too much. What is needed is a complete coverage of glue and therefore an even, smooth surface.
Use paint of high gloss and apply a coat of semi matt paint after the decal has dried. If glossy paint isn't available bring it to a glassy sheen by overspraying with transparent laquer (caution: both kinds of paint have to go together).
Details make a model more realistic, giving it a convincing look. Real details are found on the real stuff (or photos of it) the others in model magazines (especially German ones).
The left column should be self explanatory (at least I think so). If in doubt, check photos. None of the "details" on the right side are/were found on real airplanes (even tanks don't show bare metal on every edge).
Before applying any of these spurious details T H I N K !
Is that what I intend to do possible? - And if yes, can I reproduce it in scale?
In my opinion a model is a good one when in a photo it can't be distinguished from the real airplane. The most important point here are sharp trailing edges. Especially in 1/72 most models are readily discernible as such because of their rounded edges. But also in larger scales all the effort to superdetail a model is wasted when thick rounded edges on rudders and so on reveal the model at once. The manufacturers can't be blamed for this. The form needs to tell the liquid plastic where to stop.
For another exaggeration manufacturers are as responsible as modellers: Overdetailing. A kit not showing a multitude of grooves gets a bad press for lack of detail. Because lines the plan shows are missing. Here the question arises: Lack of detail in the kit or overdetailed/wrong plan? There are two kinds of plans: The blueprint in the factory and the plan published elsewhere. Apart from the almost usual omission or mistake the latter shows the external appearance of construction details as lines. The toolmaker (not necessarily an aircraft expert) now engraves these lines into the mould. Take for instance a Me (Bf-) 109. In kits you see vertical grooves behind the cockpit. Obviously panel joints. In reality not a single groove was to be seen. This part of the bird was manufactured by overlapping segments. In the 1/48 kits of the Tamiyas F4F/FM Wildcat and the Hasegawas F6F Hellcat, both manufacturers depict these vertical segments verly clearly as steps, but forgot that these aircraft weren't assembled by four inch boards. As the thickness of the original metal sheet was in the millimeter range it can't be depicted in 1/48 or less. In short: Grossly overdone!
Most wartime planes were manufactured by riveting overlapping panels to internal bulkheads and stringers. So gaps were only to be seen around doors, service panels or different structural members (rudder, ailerons, cowling and so on). As the laminar flow wing of the P-51 was very sensitive to flow distortion North American sealed every panel joint with putty and if not painted anyway gave the whole wing an overspray with aluminum color. Only the covers of the weapons bays had a distict outline. "Highlighting" such non existent panel lines may show your painting skills but not your knowledge of the real thing. Due to the high speed of modern aircraft gaps have to be kept to a minimum. Otherwise the plane would disintegrate. In general panel lines in kits are as wide as in the original. Grossly overdone too. In my opinion in 1/72 a model without such grooves is more convincing than one with them.
To cure exaggerated grooves they have to be filled with putty (slightly thinned with liquid plastic cement), sanded smooth and rescribed with the tip of a scalpel or a needle. Use of templates can be helpful. Another and very convincing way is to use a hard sharp pointed pencil for outlining all details after the model has been painted (naturally after all grooves have been filled and sanded smooth).
Not to forget sizeable rings on landing gears, especially in 1/72. In reality they were thin metal strips fixing the gear covers. The latter invariably were also of (thin) external metal sheet with some reinforcement structure welded or bolted to the inside. Again moulding restrictions are to be taken in consideration. Therefore collecting thin plastic from wherever you get is highly recommended.
Japanese paint was as good as any and the most common error is to take manually applied irregular paint as chipped paint (see page J).
To bleach paint it takes a lot of time. Not all paints detoriate the same way. Did the aircraft "live" long enough? And was the aircraft actually exposed to so much sun and heat?
In any case before applying paint see also page A, "Ageing"
Miniature still life. A real situation depicted in model form. Makes models interesting for girl friends, mothers-in-law, wifes and other natural enemies of modeling.
Miniature figurines help a lot, but only so if they show a good paint job.
The situation though fictious should depict a moment in real life. Its therefore absolutely necessary to know what the real life looked like.
Beware of propaganda photos! Mission briefings are not held in front of some aircraft, and leisurely chats with the mechanic are very scarce when enemy aircraft have to be intercepted. Equally so after landing. The deck of an aircraft carrier is crowded, windy, loud and dangerous. Nobody in sane mind would be there longer than necessary (Absolutely no chats!).
Remember also that servicing an aircraft doesn't require to strip it down to the bones. An oil check doesn't require to open the panel for the elevator trim. And if a panel is removed it isn't placed on the floor (you'd step on it sooner or later). And tools are kept in the toolbox (in contrary to Mr. Verlinden's opinion).
Well, I know such scenes are to be seen in many modelers magazines. Therefore these lines. - Think before beginning.