Need Help in Finding Out the Average Correlated Color Temperature of 4-Door Sedans, in the '70s, in the U.S.

[TV_or_not_TV]

Greetings, everyone (new member here)!
As the title implies, what was the average Correlated Color Temperature (CCT) of the vast majority of classic 4-door sedans, in the United States, back in the 1970s? What was the most common color temperature value of the majority of headlights (in Kelvin)?
To simplify matters, for reference, I've included a link containing a screenshot of a car, which shows up in a classic 1970s TV series, as, from what I've seen, most of the cars that appear in 1970s movies had the same CCT as the one in my screenshot (take a sharp look at the headlights), notice that "glacier white" color (what's the CCT value?). I need that data.
I'm interested in both the average CCT low-beam values in the '70s and the high-beam values, as well.
Note: I was born in the 1980s, so, that's why I'm asking this question.
Here's the link to it: https://imgur.com/a/mRDZdXd.
Any help would be greatly appreciated.

[joe_padavano]

When I read a post like this, my first reaction is that someone is trying to market an LED headlight for older cars that isn't annoyingly blue-white. 😉

 

I'd be surprised if that data was readily available. I can't say that anyone paid attention to color temperature in the sealed beam days, or even knew what it was, frankly. Obviously the older sealed beam lights are well into the "warm" orange-yellow range, so 2700K or lower would be my guess. Just get a couple of vintage T3 bulbs and check them yourself.

[TerryB]

Most people would look at you quite strange with that request.  Color temperature in degrees Kelvin?  In the color TV world, the white balance was indeed set to a specific color temperature.  Later the AKB circuit automatically corrected for tube emission drop off.  All of which has nothing to do with automobiles!

[joe_padavano]

2 hours ago, TerryB said:

Most people would look at you quite strange with that request.

 

Not if they have ever read the package of a new LED bulb...

 

 

[TV_or_not_TV]

12 hours ago, joe_padavano said:

When I read a post like this, my first reaction is that someone is trying to market an LED headlight for older cars that isn't annoyingly blue-white. 😉

 

I'd be surprised if that data was readily available. I can't say that anyone paid attention to color temperature in the sealed beam days, or even knew what it was, frankly. Obviously the older sealed beam lights are well into the "warm" orange-yellow range, so 2700K or lower would be my guess. Just get a couple of vintage T3 bulbs and check them yourself.

Ha-ha, good one, even though, I'm not advertising anything here!  I'm just trying to do a little research, as, just like you said, that data isn't readily available on the Internet (thought maybe someone who lived in the 1970s, in the U.S. and was into cars could help me out with that) - I looked it up on the Internet, and came up empty-handed. I'm an Electronics & Software engineer, and I need that exact data for restoring a 1973 Oldsmobile Delta 88 that I bought off from a friend of mine down in Georgia. I need to give that car that '70s look & feel to it. Frankly, I'm quite surprised to read that (2700K or lower, in the 1970s?! that's called "warm white", yet, all the film industry from that era depict the 1970s car headlights as being "cool white" - "glacier white"/"alpine white", to be exact!). In all the U.S. TV series and movies from the 1970s I've watched, the only headlight color temperature pattern used is always in the 4000K to 5000K range. Now, obviously, I know movies are not extremely accurate (after all, it's only a movie!), BUT, I assumed they, at least, got some of the aspects from that era right, especially, seeing as how all the directors agree on that CCT headlight pattern (thought it was an objective pattern). Leaving that aside, I still enjoy that car-lighting pattern, and I would appreciate it if you would take a look at the screenshot I have uploaded (just click on the link) and tell me the CCT value of the headlights - I think it's 5000K, but I'm not exactly sure.
 

 

11 hours ago, TerryB said:

Most people would look at you quite strange with that request.  Color temperature in degrees Kelvin?  In the color TV world, the white balance was indeed set to a specific color temperature.  Later the AKB circuit automatically corrected for tube emission drop off.  All of which has nothing to do with automobiles!

@TerryB : LOL, you AMUSE me! Like I previously stated, I'm an Electronics & Software engineer, and also a former Mathematics, Physics and Computer Science Olympian, so, I'll tell you this: ALL of the colors of light-bulbs are OBJECTIVELY and UNIVERSALLY calculated and specified based on the Correlated Color Temperature (CCT) value expressed in DEGREES KELVIN, ESPECIALLY in the AUTOMOBILE industry! It has EVERYTHING to do with the color of AUTOMOBILE light-bulbs! I've included 4 screenshots and 1 chart (the objective proof) from various scientific articles and encyclopedias (including The Encyclopedia Britannica!) for you to read up on (refer to "Screenshot 1.jpg", "Screenshot 2.jpg", "Screenshot 3.jpg", "Screenshot 4.jpg" and "KELVIN COLOR TEMPERATURE CHART - HEADLIGHTS.png", in the attachments section BELOW), and also 3 hyperlinks and a YouTube VIDEO link for you to READ & WATCH + EXTRA: a pair of H7 Philips DiamondVision 5000K headlight bulbs listing sold by the Philips Store on Amazon (see "EXTRA!.jpg" - NOTE: I'm not promoting it in ANY way, it's strictly a random listing, among all the other listings, for reference)! It's OBVIOUS to ME you UNDERSTAND and know NOTHING about lighting and Physics! You've got a lot of READING, UNDERSTANDING and CATCHING UP to do! End of PROOF.
Q.E.D. (Quod Erat Demonstrandum)       
Links: 1) https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/lightsources/whatisCCT.asp
           2) https://www.accessconnect.com/color_temperature.htm
           3) https://www.narva.com.au/blogs/blogs/2018/Mar/1/warm-or-cold-kelvin-light-rating
(YouTube video link): https://www.youtube.com/watch?v=PO-GIX4CStk

Edited September 16, 2020 by TV_or_not_TV (see edit history)

[joe_padavano]

1 hour ago, TV_or_not_TV said:

 BUT, I assumed they, at least, got some of the aspects from that era right,

 

HAHAHAHA. Good one!

In any case, no one had even heard the term "color temperature" in the early 70s, let alone be able to give you a reading on headlights. The original headlights were incandescent sealed beams. Light output was horrible. I don't even think you can buy them anymore. The modern halogen replacements are brighter and whiter in color. I wasn't kidding when I said that your best bet to get this data is to get your hands on some vintage T3 headlights and test them.

 

This chart is from Hella Lighting. Note that incandescent isn't even on the chart. It would definitely be to the left of halogens.

 

 

[Gary_Ash]

Halogen headlights were not used in the U.S. until the 1979 model year due to federal regulations.  So, any cars before that, including your 1973 Oldsmobile, would have had plain incandescent tungsten filaments in sealed beam housings.  Regulations also limited the brightness of headlights to 37,500 candela per side, so that also had an effect on filament design.  The lamp-making companies balanced light output against life since no one wanted to be changing sealed beam lamps very often.  Consequently, it is likely that the operating color temperatures were near 2850 K +/- 150 K.  This assumes that the alternator was working correctly, that the battery was charged, and the wiring was in good shape.

 

Computer screens, TVs, movies, and printed pictures do not accurately capture color temperature - even a wax candle flame can look "white" in a photo. 

 

EDIT:

I found my old collection of light bulb and infrared radiation calculators from General Electric.  The small, white one from March, 1969 shows some interesting data:  Raising the color temperature by 100 K over the nominal operating value for a tungsten filament increases the light output by about 30% but reduces the life to about 1/3 of the rated value.  So, you can't vary color temperature much without a BIG penalty in life.  The blackbody radiation slide rule hasn't been available for many years, but I was able to re-create its functions in an Excel spreadsheet.

Edited September 16, 2020 by Gary_Ash (see edit history)

[8E45E]

I believe the SAE would have documentation on this.

 

As well, in the US, headlights were limited to tungsten element sealed beam bulbs until 1979 or so when the new halogen bulb within a sealed beam became standard on the Lincoln.  In Canada, the European H4 and H1 bulbs for headlamps and fog/driving lights were legal, and some imports, including Citroen, Peugeot, Renault, Saab, and some others were equipped with them.

 

Craig

[TV_or_not_TV]

32 minutes ago, Gary_Ash said:

Computer screens, TVs, movies, and printed pictures do not accurately capture color temperature - even a wax candle flame can look "white" in a photo. 

Yes, I already knew that, obviously, that was the main reason I was asking that question. I never knew all the other technical information on 1970s car headlights & CCT data from that era, though, as: 1) like I previously mentioned, there isn't any data on that on the Internet regarding that particular topic, 2) like I said before, I was born in the 1980s and 3) no one else besides joe_padavano, you (Gary_Ash) and 8E45E has ever been able to provide me with that information, up until now.
That being said, I would like to thank @joe_padavano, @Gary_Ash and @8E45E for that.
Well, in that particular case, I think I'll just stick to my 5000K CCT determination and the movie-industry CCT headlight-pattern, as, although it isn't "realistically" accurate for that era (like you guys have said): 1) I do enjoy that "headlight-movie" pattern and correlated color temperature, 2) I enjoy the "uniqueness" (a bit of an oxymoron, in this specific case, though) of that shade of color, namely "glacier white"/"alpine white" and the anachronism of it all, and also, 3) for the cinematic stereotype, so, the incandescent sealed beams are out of the question, ha-ha! It's only a matter of personal choice, then.
Thanks again!
Cheers!

[TV_or_not_TV]

1 hour ago, Gary_Ash said:

Halogen headlights were not used in the U.S. until the 1979 model year due to federal regulations.  So, any cars before that, including your 1973 Oldsmobile, would have had plain incandescent tungsten filaments in sealed beam housings.  Regulations also limited the brightness of headlights to 37,500 candela per side, so that also had an effect on filament design.  The lamp-making companies balanced light output against life since no one wanted to be changing sealed beam lamps very often.  Consequently, it is likely that the operating color temperatures were near 2850 K +/- 150 K.  This assumes that the alternator was working correctly, that the battery was charged, and the wiring was in good shape.

 

Computer screens, TVs, movies, and printed pictures do not accurately capture color temperature - even a wax candle flame can look "white" in a photo. 

 

EDIT:

I found my old collection of light bulb and infrared radiation calculators from General Electric.  The small, white one from March, 1969 shows some interesting data:  Raising the color temperature by 100 K over the nominal operating value for a tungsten filament increases the light output by about 30% but reduces the life to about 1/3 of the rated value.  So, you can't vary color temperature much without a BIG penalty in life.  The blackbody radiation slide rule hasn't been available for many years, but I was able to re-create its functions in an Excel spreadsheet.

Once again, thank you kindly for your update! I appreciate it. 

[TV_or_not_TV]

If the moderators wish, they can close this topic.

Edited September 16, 2020 by TV_or_not_TV
Typo. (see edit history)

[TerryB]

Color TV picture tubes were adjusted to 6550k “whites” by controlling the cathode bias settings. Minolta made the meters we used to measure this parameter in the lab.   For 6v automobile headlights, especially those using a separate bulb and reflector, the reference color was best described as “two pi$$ holes in snow”.  I’m not sure how you equate that to degrees kelvin.

[Frank DuVal]

2 hours ago, TerryB said:

 I’m not sure how you equate that to degrees kelvin.

Well, in the chart above, a candle flame was 1000° K, so around there, just look at any 6 volt VW Beetle with typical corrosion on the fuses!😁

[joe_padavano]

55 minutes ago, Frank DuVal said:

Well, in the chart above, a candle flame was 1000° K, so around there, just look at any 6 volt VW Beetle with typical corrosion on the fuses!😁

 

Sorry, Frank, but that's not nearly as good a line as "two pi$$ holes in the snow".  🤣