U.S. insignia decals with a gray tint--what are they?

Adam, what vintage aircraft are you seeing this on?  Also, are the tinted ones colored and then greyed, or all grey?  If they are all grey, then they are probably for a low visibility scheme.  Otherwise, I am not sure what you have found.  Could you post a picture?

John

Most likely you're looking at low-vis insignias found on modern jets.

Some US WWII aircraft had their insignia & codes painted in light gray to reduce visibility to enemy fighters. Some Korean war era navy & marine  aircraft also had insignia & codes in blue/gray to reduce visibility for night operations

If we are talking about WWII era, they grayish tent is to simulate fading of the insignia. The harsh sunlight of the PTO, and the UV rays planes were exposed to at high altitudes of the ETO were not kind to the original colors painted on the aircraft.

Simulated fading or reduced visibility... Here's a link to a photo of a decal sheet:  http://imgur.com/3JBhu8V

Looks to me as though the lower aircraft in the photo had a grey background instead of white on his insignia.  May have just been a personal choice of the pilot?

The greyed areas were done solely to make them less visible in combat; the RAF did it to their roundel by either doing away with white, or making the ring too thin to be seen at distance. In the Pacific, when the red centre was deleted, the remaining circle was painted a light blue, rather than white.

Okay, so it's a visibility thing.  Interesting how the insignia changed from star-in-circle to stars-and-bars to increase the recognizability (if that's a word) of a U.S. insignia, to then downplaying its visibility.  I wonder if that evolution took place once it was determined that the U.S. was gaining air superiority.

Yes, it was a camouflage/visibility thing. "Grayed out" stars were most common on USAAF aircraft in the ETO in 1942/1943. By the time the white bars were introduced, first with the red surround, and later with the blue border, the practice was less and less in use. It was usually done at the unit level, such as squadron or group. Heavy Bomber and Medium Bomber units were the most frequent users of the practice. It was not commonly seen on fighters as often due to US fighter types having the opposite problem- confusion with Luftwaffe fighter types. So they tended to use more prominent ID markings as a result.

It was also done with the squadron code letters of the English-based bomb groups starting about early 1943 as I remember from Freeman's "The Mighty Eighth".  The letters changed from Insignia Yellow to gray.

That depended upon the Fighter & Bomb Group. When the codes were introduced they were painted on in gray, white or yellow. Again it was quite dependent  upon the sub unit such as Wing or Group, rather than at Air Force level. For example, the 91st Bomb Group kept their Yellow codes on OD B-17s all thru the war.

It was a practice started in the 8th Af on B-24s... The fuselage insignias had the star & bar "greyed out" to deny the Luftwaffe pilots an "aiming point" on flank-attacks. It subsequently went on to be applied to all types, but sheer numbers prevented it happening to all aircraft in the 8th, so instead of a general order, it was left to individual squadron & group COs as an option.

This followed the removal of the roundel-star insignia from all US aircraft from the right wing upper and left wing lower surfaces.

This practice was also to deny enemy pilots an aiming point of "Shoot between the stars" to hit the cockpits during a high or low-side deflection attack...

The Star & Bar insignia was put back on the lower right wing of some P-47s after D-day to increase recognition for Allied anti-aircraft gunners due to the Jugs being utilized heavily in ground attacks ("Rhubarbs") in proximity to Allied ground units.

The red center on early US insignia was removed just prior to the Battle of Midway, to preveant friendly-fire incidents by gunners mistaking the red center for Japanese hinomaru. Ted Lawson mentioned this in his book, "Thirty Seconds Over Tokyo", as an explination of why Japanese civilians were waving at his B-25 as they flew overhead. (More likely that they just assumed any aircraft over Japan were theirs, though)

The addition of the red surround in 43 was short-lived because of PTO airgunners' reports of them still "seeing red" and firing on other US planes in the heat of battle (That's also where the expression of "makes me see red" came from)

USAAF aircraft in the MTO and ETO did not routinely have the stars on both upper and lower wing positions in 1942/1943 prior to introduction of the white bars and red outlined insignia in June 1943. That was a USN PTO marking practice. AAF aircraft in the PTO were usually operating under a Navy area command, and as such had to conform to their regulations. Check out Dana Bell's Air Force Colors volumes I, II, & III for a full breakdown on what marking practices were in place at what time period and where.

One thing I've missed seeing any photos of, is one in which the greyed-out insignia is applied to the upper or lower wing... Was it confined to just fuselages?  

Upper wings as well.

I believe this is what grayed insignia is being talked about. The bottom plane has grayed insignia on fuselage and wings

Here we go.... (now that i have a real computer and not my phone...)

compare the stars on the fuselage to the later added bars

even the 1st Air Division triangle appears to be grayed out on this 306th BG B-17 in Summer 1943. 

and on some B-26s

Stik, the first B-17 is one from the 1st AD, 303rdBG, while the second B-17 is from the 305th BG, 1st AD, before it went to Depot, and sent to the 381st BG when it was lost on October 14, 1943, Black Thursday.  "Viscious Virgin" also had the triangle grayed out as can be seen by the white plane in squadron letter.  The 303rd used white when they could not get Insignia Yellow paint.

I had a different version of this image on my last post... it shows on the desktop but not on my laptop, so in case it did not show on anybody else's device, I'll try it again. I believe these re 91st BG B-17s in late 1942 or early 1943.