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Casey

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  1. If you have 3D printer, there are also pretty good models for doing it quite simply https://makerworld.com/en/models/569910
  2. This is just a measurement from a different reference. I do not claim that Neutral Grey 43 was of any particular color in history The measured LAB of Neutral Grey 43 in Official United States Aircraft Colors 1908 - 1993 - US Army Air Service and Air Corps Colors 1908-1941 L*: 44.3, a*=-1.23, b*=1.44. It's sRGB color (means D65/2 deg conversion with sRGB gamma) is If you want to replicate it using Tamiya Acrylics, try simple recipe 1:1:1 mix of 1 parts XF-12 - J.N. Grey 1 parts XF-24 - Dark Grey 1 parts XF-51 - Khaki Drab
  3. I doubt it was even a metallic paint. This thing is huge and it'd need a lot of metal flakes. The reflections you see are normal behavior of larger size of neutral painted object. Please look at the color reflections of yellow and blue planes on the lower wing side of Goose on photo from the museum. You don't need metallic paints to have it work that way, and the plane is not even glossy. I'd say it was low satin, but I had no glossmeter with me so it was my subjective check up-close.
  4. I was using this plane only as an currently existing object that is an airplane sized, is painted in spectrophotometer measured Neutral Grey and demonstrates the behavior of that paint under different light conditions. Spruce Goose is made of mostly wood and with restrictions on use of wartime strategic materials. Neutral grey would be the cheapest option.
  5. And here is the above exact Spruce Goose real color as measured by spectrophotometer:
  6. Some technical explanation: D65 standard daylight in measurements means that the object is illuminated by 6500K black body radiation passed throuh atmosphere. This color is, in reality, very blue. The jagged curve of D65 is a result of atmosphere effects on sunlight (gases absorption and emissions, Rayleigh scattering ect.) Still, there is much more blue light irradiance in that resulting illuminant spectra. Now, if you aim that light onto neutral paint it'll come back with the same shape (multiplied by how dark the paint is, say multiplied by X% for some mysterious neutral grey) because relative reflectance of neutral paint is flat. Now comes the problem of white point selection. Humans are funny beasts, we define what is white 'on the fly'. Let's assume we defined D65 as white. That means white is in fact corresponding to heavy blue shifted color. Now, imagine your camera picks a white point reference of 5000K. That color is way less blue and 5000k becomes interpreted as neutral white from now on. But at the same moment, 6500k light reflected from neutral grey object will be interpreted as blue. This is more or less what happens at the photo above. Only if you know the real illuminant and the measured reflectance relative to that illuminant is when you can make any assumptions about the object real color - which is what spectrophotometer does. Also, that same reason means thay without measuring the book itself it is hard to even say what the color in the book really is Photo based speculations are just speculations at this point.
  7. Nick recipe referenced above excludes blue possibility in paint itself. But there is another thing he mentioned: N colors have perfectly flat reflectance which means they effectively take color of the surrounding objects very easilly. You can see it for example on this plane painted in true neutral color: How do I know it is neutral? I have been there with spectrophotometer. Spruce Goose plane is not painted blue grey. It is absolutely flat neutral. All you see on the photo above is combination of camera white point adjustment and blue sky. Once I get back home I'll get the spectra of this particular plane paint color.
  8. This color on this photo is not only bluish, it is outright blue. And it is very not like the sample in Official United States Aircraft Colors 1908 - 1993 - US Army Air Service and Air Corps 1908 - 1941 If two sources have different results, you need to pick one which is the reference So, which one is the better reference? (I suspect it can be OUSAC, mostly because this color is suspiciously similar to neutral gray used on some air planes I saw, and also neutral color was always, well, neutral, but I leave that decision to others!)
  9. I do, from Official United States Aircraft Colors 1908 - 1993 - US Army Air Service and Air Corps 1908 - 1941 I haven't measured them on my newest device, so I only have bit old data. Want me to re-measure them? And no, Neutral Gray 43 is not blue. Maybe hobby paints don't bother making neutral paint since mix of black&white is good enough?
  10. Here are the colors: Conversion to RGB swatch is using sRGB conversion, with CIE 1931 2 Degree Standard Observer, D65 illuminant and CAT02 chromatic adaptation (https://en.wikipedia.org/wiki/CIECAM02#CAT02). And then squished to closest integer in 0-255 ranges destroying all the math RGB sucks. NS Light Gray CIELab d/8 (D65/10°) L*=73, a*=0, b*=1 Recovered reflectance curve: Recipes: ICM Acrylics (Volume) 1 parts ICM-1001 - White 3 parts ICM-1029 - White Grey 1 parts ICM-1034 - Dark Sea Grey 1 parts ICM-1044 - Basic Skin Tone DE00: 0.58 ICM Acrylics (Mass) 3 parts ICM-1001 - White 1 parts ICM-1034 - Dark Sea Grey 1 parts ICM-1044 - Basic Skin Tone DE00: 0.64 Tamiya Acrylics (Volume) 6 parts XF-02 - Flat White 2 parts XF-19 - Sky Grey 1 parts XF-20 - Medium Grey DE00: 1.14 Tamiya Acrylics (Mass) 6 parts XF-02 - Flat White 2 parts XF-19 - Sky Grey 1 parts XF-20 - Medium Grey DE00: 1.10 Tamiya Lacquers (Mass) (I do not have enough paints measured to make an easier mix) 16 parts LP-02 - White 1 parts LP-25 - Brown (JGSDF) 8 parts LP-34 - Light Gray 4 parts LP-36 - Dark Ghost Gray 1 parts LP-59 - NATO Brown DE00: 1.75 Liquitex Basic Acrylic Fluid (Mass) 1 parts #432 - Titanium White 2 parts #434 - Unbleached Titanium 1 parts #599 - Neutral Gray 5 1 parts #680 - Light Blue Violet 1 parts #810 - Light Pink DE00: 0.58 Golden Fluid Acrylics (Mass) 1 parts #2370 - Titan Buff 3 parts #2371 - Titan Green Pale 1 parts #2380 - Titanium White 2 parts #2401 - Ultramarine Violet DE00: 0.64 Dark Earth CIELab d/8 (D65/10°) L*=49, a*=6, b*=14 Recovered reflectance curve: Recipes: ICM Acrylics (Volume) 1 parts ICM-1008 - Deep Brown 2 parts ICM-1035 - Grey-Green 1 parts ICM-1040 - Beige 1 parts ICM-1059 - Green Ochre DE00: 0.38 ICM Acrylics (Mass) 1 parts ICM-1008 - Deep Brown 2 parts ICM-1035 - Grey-Green 1 parts ICM-1042 - Pale Sand 1 parts ICM-1059 - Green Ochre DE00: 0.41 Tamiya Acrylics (Volume) 1 parts XF-04 - Yellow Green 1 parts XF-09 - Hull Red 1 parts XF-21 - Sky 1 parts XF-60 - Dark Yellow DE00: 0.41 Tamiya Acrylics (Mass) 1 parts XF-10 - Flat Brown 1 parts XF-14 - J.A. Grey 2 parts XF-60 - Dark Yellow DE00: 0.49 Tamiya Lacquers (Mass) 2 parts LP-34 - Light Gray 1 parts LP-57 - Red Brown 2 2 parts LP-59 - NATO Brown 1 parts LP-83 - Mixing Yellow DE00: 0.5 Liquitex Basic Acrylic Fluid (Mass) 1 parts #330 - Raw Sienna 1 parts #331 - Raw Umber 1 parts #430 - Transparent Mixing White 2 parts #590 - Brilliant Purple 1 parts #680 - Light Blue Violet 1 parts #830 - Cadmium Yellow Medium Hue DE00: 0.36 Golden Fluid Acrylics (Mass) 2 parts #2350 - Raw Umber 3 parts #2370 - Titan Buff 1 parts #2385 - Transparent Red Iron Oxide 3 parts #2401 - Ultramarine Violet 1 parts #2410 - Yellow Oxide DE00: 0.39 Dark Green CIELab d/8 (D65/10°) L*=43, a*=-1, b*=6 Recovered reflectance curve: Recipes: ICM Acrylics (Volume) 1 parts ICM-1035 - Grey-Green 1 parts ICM-1038 - German Grey 2 parts ICM-1059 - Green Ochre DE00: 0.40 ICM Acrylics (Mass) 1 parts ICM-1035 - Grey-Green 1 parts ICM-1038 - German Grey 2 parts ICM-1059 - Green Ochre DE00: 0.33 Tamiya Acrylics (Volume) 1 parts XF-25 - Light Sea Grey 1 parts XF-27 - Black Green 2 parts XF-52 - Flat Earth DE00: 0.30 Tamiya Acrylics (Mass) 1 parts XF-25 - Light Sea Grey 1 parts XF-27 - Black Green 2 parts XF-52 - Flat Earth DE00: 0.39 Tamiya Lacquers (Mass) 4 parts LP-25 - Brown (JGSDF) 1 parts LP-36 - Dark Ghost Gray 2 parts LP-59 - NATO Brown 1 parts LP-68 - Clear Blue DE00: 0.50 Liquitex Basic Acrylic Fluid (Mass) 4 parts #128 - Burnt Umber 2 parts #599 - Neutral Gray 5 2 parts #660 - Bright Aqua Green 1 parts #770 - Light Blue Permanent DE00: 0.30 Golden Fluid Acrylics (Mass) 2 parts #2350 - Raw Umber 1 parts #2371 - Titan Green Pale 1 parts #2386 - Transparent Yellow Iron Oxide 1 parts #2400 - Ultramarine Blue 1 parts #2407 - Yellow Ochre DE00: 0.38
  11. I have very limited selection of UA paints, and I've tested only those that were in the corresponding theme sets.
  12. Would you like me to make recipes for those too?
  13. You are getting there, the first layer was quite uneven which can be seen on the model, and the next layers do not cover the plastic color (yet). Airbrush can help you do it much faster, but for white you need more layers. Humbrol enamels were much easier because they were enamels, they flow very differently on plastic, tend to self level and also dry much slower which makes them more forgiving. But there is one more good thing you can do with acrylics: If you feel that the above model needs a 'new attempt', simply soak them in IPA (not the beer though), it'll remove the paint.
  14. Here is comparison: Target: ANA623 | Glossy Sea Blue 623 | GU 2.1, 17.1, 36.3, RGB: #464D55 (L*=32.69, a=-1.50, b=-5.32), Light source/angle=D65/10, RGB conversion=srgb Closest sample in: Tamiya Areosol (compared with 1 samples) DE00: 2.99 - #3F4D59 - AS-8 | Navy Blue | 0.5 | 5.0 | 18.1 (L*=32.47, a=-3.22, b=-8.38) It is a borderline match, with ~3.0DE color difference. Having near identical lightness level the difference comes only from difference of color and saturation. It is too blue and too green (and because of that - it is more saturated blue) Additionally, it has flat surface, while the target should be satin. Real amount of difference is not shown well by RGB simulations. Please look at the spectral data:
  15. Here are the recipes for the above LAB data: Notes: The LAB data was used to recover spectral curve using: Jakob, W., & Hanika, J. (2019). A Low-Dimensional Function Space for Efficient Spectral Upsampling. Computer Graphics Forum, 38(2), 147-155. doi:10.1111/cgf.13626 The matches are using only the paints I've measured. I use D65/10 illuminant/observer and D/8 SCI geometry for the device ICM by VOLUME ICM by MASS Tamiya Acrylics by VOLUME Tamiya Acrylics by MASS Tamiya Lacquers by MASS Liquitex Basic Acrylic Fluid by MASS Golden Fluid Acrylics by MASS HTH!
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