Hi all - I’m finishing up an F-104, and I painted the major part of the fuselage about three months ago (olive drab and neutral gray) using Model Master’s Acryl. When I painted the intake scoops yesterday they are an obvious shade lighter. Could the original paint on the fuse have darkened over the three months? Could the clear coat have made a difference? It’s been kept out of direct sunlight.
stinger
Wet paint and dry paint rarely are the same shade. I haven’t noticed an appreciable darkening with age. Usually any color change is due to a varnish.
With Tamiya acrylics, I noticed that it seemed like the paint did change color as it cured. If MM Acryl does the same thing, it may well be that your intake scoops will darken over the next day or two to match the fuselage.
Paint does darken as it dries, and some paints change color as they cure. Most (but not all) modern pigments are pretty stable, and all are very stable unless exposed to ultraviolet light or some other destructive agent. Most binders in modern paints are also very color stable, again with the same exceptions.
If the color of the fully cured paint is not the same, then it is likely that it was not completely mixed either the first time you applied it, or the second.
I was careful to make sure that the paint was fully mixed, and it has been a full day now, so I’m sure it is dry enough (especially at this mile high (dry) climate).
I had on hand a test piece of styrene that had the original paint on it, so I sprayed a line of the new over that original sample. I have the sample in direct sunlight now waiting to see if it changes.
I guess only time will tell. Even though the scoops are now attached to the model, at least I can mask it off and respray it if I need to.
Thanks to all for the info and help.
stinger
This might be the key to your question. If the previous work has been gloss coated and the new paintwork hasn’t, then the “old” paint work could definitely appear to be darker.
The difference lies in the way that a “flat” surface and a “gloss” surface reflect light, but the best analogy I can make is to throw a bucket of water over a concrete driveway and see the difference. You are not changing the colour at all, just the reflectivity of the surface.
The entire model (before the scoops) received a coat of Future for the decals, then a clear flat coat. The color on the scoops is now just a coat of flat paint, so I see what you mean. All those other layers on top of the raw paint certainly could make the difference. I’ll repeat the process above on the scoop area and see what results from it.
Thanks for the advice,
stinger
Good catch, Phil! I should have read the original post more carefully.
Absolutely, the clear coat makes a huge difference. Smear a drop of water over a flat paint surface and you will see what I mean.
All the above makes perfect sense. Since the subject has come up, though, maybe it’s worth talking a little about the general effect of age on paint. I learned some interesting stuff about that, albeit in an extremely informal, un-scientific way, when I was working as a curator in a maritime museum some years back.
Modern paints are wonderful, sophisticated things, but any paint is going to change color at least a little bit as it gets older. The worst enemy of a painted finish (or virtually any other form of coloration) is light, and the most damaging form of light is sunlight. I can get out of my depth in a hurry here, but I do know that sunlight contains a high concentration of rays at the ultra-violet end of the spectrum, and ultra-violet light is devastating to paints, inks, and dyes. Red seems to be especially susceptible.
I once had two identical copies of a paperback book, printed on glossy paper, in my office. One item on the cover was an American flag. I left one copy on a shelf in the shade, and accidentally left the other one on my desk, where the sun hit it for several hours each day. Over a period of three or four months the red on the flag that was in the sun disappeared completely; it looked like the flag had been printed in grey.
Quite a few years ago I paid a visit to the British Army Museum, in London. Red-dyed fabric is pretty important to that institution. Visitors were warned before they entered that the light levels were kept extremely low, in order to preserve the uniforms, battle flags, etc. It was so dark in the galleries that I was afraid of falling over something - though of course my eyes eventually got used to it. That was quite a long time ago; I don’t know whether that particular museum may have come up with a better solution to the problem since then.
If you want your models to last, keep them out of the sun. If there’s no way to avoid letting sunlight fall on them, look into the possibility of putting UV-proof film on the windows. This stuff used to be available only to the museum and preservation trade, but recently places like Lowe’s and Home Depot have started selling it. (It also cuts down on heat, lowering your air conditioning bill - and raising your heating bill in the winter.)
The second-worst light source is flourescent light, which also has a pretty high UV content. It’s nowhere near as dangerous to models as sunlight is, but it makes sense to avoid it if possible. You can buy UV-blocking plastic tubes that slip over flourescent tubes; if you have a big, valuable model collection that has to be kept in that kind of light, those tubes might be a reasonable investment. (They don’t cost much.) Nowadays dealers sell quite a variety of flourescent tubes that give off dramatically different kinds of light for different applications; if you want your models to look their best to the human eye, it’s worth taking a look at what’s available.
To my eye, most models look their best under plain, old-fashioned incandescent light. The good old light bulb casts a warm, friendly light that, though the harsh shadows it casts can sometimes be distracting, shows off the detail and color of the typical model at its most attractive. When I was at the museum I discovered that old ship models, like old people (such as myself) tend to look better when the light isn’t too bright and harsh.
Hope a little of that is of at least a little interest. Lighting can make a surprising difference in how a model looks - and on how long it lasts.