Author Topic: aircraft paint opacity  (Read 2604 times)

Offline Berman

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aircraft paint opacity
« on: July 03, 2013, 03:03:15 AM »
 I have seen articles on various techniques to simulate sunlight passing through the upper wing and its representation on the lower surface. I can understand seeing a semblance of the framework if the wing is entirely covered with clear doped linen. However, I have seen models with a subdued color fuzzy edged representation of the red, white, and blue cockade on the lower surface. As these colors were not translucent, would it not be more accurate to display the shadow of the cockade in grey tones? Or can you detect colors through the lower surface. Photos of  reproduction aircraft would be useful to determine the truth.
  Regarding aircraft with PC-10 upper surfaces and CDL lower surfaces, PC-10 was a very opaque finish as it was composed a combination of yellow ochre and lamp black. I do not think it would be possible to see any framework detail through the lower surfaces from the effect of sunlight.   Is representing lower wing framework, on say a Camel, factual or artistic license? Your thoughts please.

Offline coyotemagic

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Re: aircraft paint opacity
« Reply #1 on: July 03, 2013, 05:39:10 AM »
Hi, Barry.  As to the translucency of roundel colors, I have no photographic evidence at my finger tips but I have seen it.  I'll have to poke around a bit more.  However, in re the difference in CDL shades on the undersides of wings where an opaque color (PC10, PC12, camo patterns, etc.) is used on the upper surface, I can say with conviction that the CDL over the ribs appears lighter than the surrounding area.  This is a photo of Javier Arango's SE5a repro which I had the honor of viewing up close at Paso Robles. 

Cheers,
Bud
« Last Edit: July 03, 2013, 05:40:49 AM by coyotemagic »
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Offline Des

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Re: aircraft paint opacity
« Reply #2 on: July 03, 2013, 08:03:18 AM »
Here is a classic example of opacity, the wing and fuselage framing are clearly visible as is the cockade on the top wing, a hint of red can be seen, the blue would show as just a dark shadow.

Des.

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Offline Ian from Doncaster

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Re: aircraft paint opacity
« Reply #3 on: July 03, 2013, 05:05:43 PM »
Also, with CDL on the lower surfaces, and PC10/12 on the upper, the lower surface appears glossier where the ribs are and duller in between.  This could be due to the linen holding a little more tension over the ribs?

I do like the concept of using artistic licence sometimes.  It's ok to produce rib shadowing on an aircraft where it wouldn't appear in reality, where the modeller wishes to practice the technique?

Offline JoeDxMB

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Re: aircraft paint opacity
« Reply #4 on: July 04, 2013, 05:11:01 AM »
Also, it  would seem to me that where the darker areas are more prominent would depend on if the (bright ) sun was shinning through the wing or not.

So, it might come down to how  you want your model displayed as depicting.
Is there really a right or wrong way ?

« Last Edit: July 04, 2013, 05:17:38 AM by JoeDxMB »

Offline ALBATROS1234

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Re: aircraft paint opacity
« Reply #5 on: July 04, 2013, 05:01:11 PM »
also i like to think of models as sorta like a stage actor. even men wear full face of make up to accent the eyes lips and ruddyness in the cheeks. so we tend to over accentuate  details like ribs etc to give that same effect as a stage actor trys to do so the face wont look like a "cotton ball" from a distance under lights. we do it so it wont look so monotone,plain and toyish. plus its great fun.

Offline Steven Robson

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Re: aircraft paint opacity
« Reply #6 on: July 13, 2013, 03:38:10 PM »
I have to pause for a moment and respond to this very interesting topic.  I’m rather passionate about the shadows of wing spars on the underside wings of our models.

Des’ photo is excellent and please note: the rather dramatic or distinct shadows in this photo are taken of an aircraft in flight and at a distance.  The intensity of the shadows is an artefact or result of the lighting conditions when the aircraft was photographed.  Note: I also don’t usually comment on non-German aircraft.

I align myself with The Red Baron’s comments about tending towards Representation.  Usually, our audience, at the model shows, are seeing our aircraft on the table, not in flight.  We also (modellers) enjoy our models in our display cabinets, not in flight.  So, the intensity of the shadows cast by the wing spars needs to be a little (or quite a bit) less than an aircraft represented in flight, like in Des’ photo.

Do not underestimate that all photos, are themselves representations, and not the real object.  And also remember that your visual experience of even seeing a WW1 aircraft flying over your head, like in Des photograph, is also a representation of the object, mediated by your optic nerve and by a set of innate visual expectations in the viewer.

Seeing any scale model (object) carries with it, a set of visual expectations from the audience.  We all experience this when we are weathering our models.  While weathering, our models  can come alive (this is very exciting), and then, if we over-do the weathering, right in-front of our eyes, we’ve lost it!  The model doesn’t look as good.

Why is this so?

It’s because we are dealing with an optical illusion and visual perception.  Plastic model wings are opaque, we must represent an illusion of light shining through a linen wing and casting shadows because of the wing spars.  Wing spar shadows are appropriate for the underside of wings, not the top of wings.

Much confusion results from period photos of aircraft (usually) taken on the ground and in variable lighting conditions.  Silver-grey on the factory Pfalz was opaque, no shadows here.  Olive green on upper surfaces of Allied aircraft was also opaque, no shadows here.  Lozenge printed wings on German aircraft was semi-translucent, subdued shadows here and we’ll still see a fuzzy outline of the national insignia.

Sorry about carrying on a bit.  But presenting good optical illusion (Representation) strikes at the heart (or art) of good modelling.  And this makes all the difference.

Yes, represent wing spar shadows and keep it subtle unless you’re photo-shopping your models and presenting them in flight.

On the issue of coyotymagic's (aka Bud) photo of the SE5A, with the wing spars presenting lighter than the surrounding linen.  This is a result of the aircraft being photographed in-doors, wheel the SE5a outside and the spars would likely to cast a faint shadow or non at all because of the opaque paint on the upper surface.  Representing wing spars in a lighter colour than the surrounding wing fabric is an artifact of modellers masking off the wing spars of their models and darkening the surrounding fabric with over-spray or weathering and then removing the masking tape.  In Bud's photo, the light is being reflected off fabric under different tension and from different angles, hense the change in colour. 

Happy Landings
Steven Robson   
« Last Edit: July 13, 2013, 07:40:16 PM by Steven Robson »
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Offline Ian from Doncaster

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Re: aircraft paint opacity
« Reply #7 on: July 13, 2013, 05:56:37 PM »
I'm with Bud on this one, in the main, as the lighter rib effect is what I have seen with my own eyes in several museums.

However, I also think the shadow effect as seen is Des' photo is very striking and it takes some great painting techniques to reproduce this on a model constructed of opaque plastic.

Ultimately for a free-standing model displayed in the privacy of your home, it is whatever takes your fancy.  We sometimes display our models suspended or on clear stands to appear to be flying, but the props aren't spinning and more often than not will be piloted by the Invisible Man!

Putting a PC-10 upper-winged model on the ground in a diorama setting, with underwing rib shadows, may not be appropriate for a competition or exhibition.

Offline Des

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Re: aircraft paint opacity
« Reply #8 on: July 13, 2013, 06:35:10 PM »
Here are some more examples of the light passing through the linen to highlight the ribs and spars, note the different lighting conditions, even under poor light the ribs and spars still are visible.

Des.







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Offline Des

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Re: aircraft paint opacity
« Reply #9 on: July 13, 2013, 07:18:52 PM »
Viewed from above.

Des.

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Offline Steven Robson

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Re: aircraft paint opacity
« Reply #10 on: July 13, 2013, 07:52:25 PM »
This is a most fasinating thread.

I think Ian from Doncaster is on the money.  Tension in the wing fabric does make a difference, and this difference is in the angle of light reflected back to the camera (or eye) for the photo.  we'd all agree the fabric is the same colour.  The rib spars change the angle of the reflected light from the same coloured surface.  We can all do this with a piece of white paper from our computer printers by bending it.  Yes, I trust Ian's eyes and what he's seen in the museums.

Please note: a facinating example of this effect in the Wingnut wings: German Rib Tapes for Lozenge Decal Sheet  No: 30005.  The same wing photographed from different angles and the upper rib tapes changing quite markedly from dark to light in a B&W photo. 

Des' upper photo of the Pfalz, I believe, is also illustrating this point.  That is to say, the upper wing rib tapes are different (darker) not because we can see shadows of the underlying spars but a difference in the angle of reflected light.  The tensioned wing fabric between spars is slightly concave and the wing fabric that's compressed directly under the spar is flat.

Steven

Yes, late reading of the Rittmeister while writing this post, and I agree, I see rib tapes darker than the wing because they are reflecting light at a different angle.

Hmm.. Do you know the other aspect of Des photo that I didn't really consider, at first view, it that the spars themselves, with or without any back-lighting may show through the linen wings.  This can't be dismissed, and, would add a great deal of complexity to this issue.  So, I'm now more confused than when first reading the thread.  Will have to go my local aviation museum with the camera and catch some of this phenomena.  Any thoughts?

JoeDxMB makes a very good point, is there a right or wrong answer?  Likely not, so long as you carry a convincing representation to the viewer. 
« Last Edit: July 13, 2013, 08:18:08 PM by Steven Robson »
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Offline coyotemagic

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Re: aircraft paint opacity
« Reply #11 on: July 14, 2013, 04:23:19 AM »
Here's a photo of a Sopwith Tabloid from the same collection as the SE5a, taken in the hanger under poor lighting conditions.  No backlighting whatsoever, yet the wing structure, and even the roundel colors, show through.  Now bear in mind, this is a very small plane with a fairly thin wing, covered in unbleached linen.  These aircraft are displayed in a manner similar to how our models are usually displayed.  These are the effects I struggle to replicate with my models.




Now, the Bleriot is a different story alltogether, due to the use of wood and metal battens and darker rib tapes.


I hope these photos help.
Cheers,
Bud
"All men dream: but not equally. Those who dream in the dark recesses of the night awake in the day to find all was vanity. But the dreamers of day are dangerous men, for they may act their dreams with open eyes, and make it possible." -T. E. Lawrence

Offline Steven Robson

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Re: aircraft paint opacity
« Reply #12 on: July 14, 2013, 06:34:22 AM »
I agree, the roundel can be seen on the underside of the Tabloid's top wing without direct backlighting.  And the wing structure is also visable.  These are certainly subtle effects, I also struggle to achieve this on a model.  As our Baron points out, it is an effect seen on CDL.  I also believe this occurs on German Lozenge covered wings, under the right lighting conditions.  I've been through all my Datafiles and can't see these effects when the linen has been painted.

Paul Carpenter aka Carpo has an excellent tutorial on how to achieve these subtle CDL effects on models.  It would make a very useful additon to this thread.

Steven

« Last Edit: July 14, 2013, 06:45:38 AM by Steven Robson »
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Offline coyotemagic

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Re: aircraft paint opacity
« Reply #13 on: July 14, 2013, 07:07:45 AM »
Good photos that underline the unique nature of CDL, but I've yet to see any silhouettes or shadows on a painted surface.
Well, mate, you won't.  I think we're pretty much in agreement about that.  The opacity of PCs and paints is just too great to allow any light to pass through.  The Fokker wing was painted, top and bottom.  No sign of structure at all.  The Camel, although flying in bright sun light, shows no structural shadows, either.  Protective coating obviously doing it's job.  Sorry these photos are not more clear.  I think I was too excited to keep the camera steady.








Cheers,
Bud
"All men dream: but not equally. Those who dream in the dark recesses of the night awake in the day to find all was vanity. But the dreamers of day are dangerous men, for they may act their dreams with open eyes, and make it possible." -T. E. Lawrence

Offline coyotemagic

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Re: aircraft paint opacity
« Reply #14 on: July 14, 2013, 07:17:31 AM »
I agree, the roundel can be seen on the underside of the Tabloid's top wing without direct backlighting.  And the wing structure is also visable.  These are certainly subtle effects, I also struggle to achieve this on a model.
I sometimes go overboard with this, Steven, and end up with a result I can live with, rather than one I'm happy with.

Paul Carpenter aka Carpo has an excellent tutorial on how to achieve these subtle CDL effects on models.  It would make a very useful additon to this thread.
Paul is truly a master of this art form.  Red ain't no slouch, either.  Check this out.
http://forum.ww1aircraftmodels.com/index.php?topic=597.135
Cheers,
Bud
"All men dream: but not equally. Those who dream in the dark recesses of the night awake in the day to find all was vanity. But the dreamers of day are dangerous men, for they may act their dreams with open eyes, and make it possible." -T. E. Lawrence