TK-41 Question

[vallieone]

Reading a number of the threads here reminded me of an incident from my childhood.

I attended parochial school back in the 50's and was taught by the Sisters of St. Dominic who had worn black and white habits. My teacher was also part of the choir of St. Dominics and the nuns were invited to perform on the Perry Como show which was broadcast in color from the old Brooklyn studios.

The following morning after the show she showed up in class with her white habit tinted yellow and apologized to us for her appearance since the producers requested that their habits be tinted yellow due to the color cameras having difficulty picking up the white habits.

Was there a problem with the cameras as she stated? Always wondered about that.

Thanks

George

[John Hafer]

If I remember, the older color cameras had problems with highlights in that the whites could often reproduce as color, sometimes blue or magenta (purple). I think the dynamic range of the older cameras was very limited.

I remember when I used to watch the Jack Parr Show on NBC Friday nights at 10:00 PM EST back in 1964. The set used RCA TK-41 cameras and when a guest would sit under the spotlights and interview with Jack Parr, their white shirts would, at times wash out to a slight purple or bluish color. It was minor but would show up that way.

[old_tv_nut]

The gamma correctors in the TK-41 had less correction than would be desirable to compensate for the receiver, due in part to a desire not to amplify the shadow noise too much. AS a result, there was always a balancing act between getting the flesh tones not to be too dark while not overexposing whites or bright reds. Men were often dressed in blue shirts, or I have heard, sometimes light gray.

This is the first time I have heard of yellow being used to tone down the whites.
Was the tint very yellow, or more of a beige off-white?

[vallieone]

Thanks for the replies.

If memory serves me it was not bright yellow but closer to the beige family but a stark contrast to the normal crisp white habits that they wore.

George

[Aussie Bloke]

Interesting to hear these facts on the old TK-41s.

I know in modern studios in Australia the lighting is set to an orangy colour and the camera white balance is adjusted to make it look of normal colour, I assume this is done to bring out the reds in the flesh tones as it seems to be the desire these days for people to look beat red on TV lol.

Anyhow I somewhat assumed yellow was used because of the bright spotlights back then would of overexposed the whites and lighter colours hence yellows looking like normal whites, but after reading the replies from the experts makes me wonder if the white balance on the TK-41s is at that of a yellow colour?

[old_tv_nut]

Running incandescent studio lighting at 70% for the base setting has been a long-term practice, since before color started. It greatly increases the bulb life, and provides a base light from which the lighting director may go up or down. The cameras would have been (or should have been) white balanced on this base level.

Regarding the use of toned white clothing, since the white color of a TV set is nowhere near the typical 2750K home lighting, fudging the color of white objects is likely to be unnoticed unless someone comes on screen with a real white shirt.

[old_tv_nut]

An August 1954 SMPTE Journal paper "CBS Color Television Staging and Lighting Practices," (which referrerd to the newly adopted NTSC system using either TK-41s or the Chromacoder) said that a "tattle-tale gray" must be used in place of the light blue or tan fabrics used in black and white. The reflectance suggested is 60%. [For those too young to recall, "tattle-tale gray" was an advertising phrase for something to be avoided by use of a certain brand of clothes-washing detergent.]

This article also explains that incandescent lamps can be dimmed about 30% by reducing the voltage from 120V to 110V, which incidentally reduces the color temperature by about 100K and increases the life by about four times. The article claimed that image orthicon color cameras could be white balanced succesfully with incandescent color temperature as low as 2300K.