8mm Forum: Color correction filters for reddish prints

This is topic Color correction filters for reddish prints in forum 8mm Forum at 8mm Forum.

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Posted by Pablo Alvarez Roth (Member # 655) on August 28, 2007, 01:09 AM:

Hi everyone, has anyone bought these filters, there´s a person in ebay selling them, I might give them a try?.

cheers
pablo.

Posted by Joerg Polzfusz (Member # 602) on August 28, 2007, 06:26 AM:

Hi,

it's most likely the "COLOR REBALANCE FILTER" as sold by Wittner:
http://www.wittner-kinotechnik.de/katalog/07_vorfu/a_allgem.php
(There's a "with and without"-picture on the page, too.)

There has been a test in the "Schmalfilm" some years ago. If I remember correctly the test-result was:
* Works fine on not too reddish films
* Can't save anything once the film is completely "black & red & white"
* Reduces the amount of light on the screen

Unfortunately the test doesn't seem to be availble online and I'm away from my magazines at the moment.

And no, I haven't used this filter, hence I'm my knowledge is restricted to the above test.

Jörg
P.S.: This seems to be the only "test result" available online:
http://forum.filmvorfuehrer.de/viewtopic.php?t=618&view=previous&sid=8d6f332466c08ab1eda1a50d669dcd01
Short summary/translation:
* The filter also gets hot. Hence one of those filters got destroyed by the heat while projecting "Lawrence of Arabia" (it's unclear whether this was a projection in Super8 or 70mm or something in between).
* It depends on the film's reddishness whether the filter is the correct one.
* The filter also reduces the contrast and negatively affects the white-balance. "stefan2" states that it's a matter of personal taste whether someone prefers the filtered version over the unfiltered one. "stefan2" claims that he doesn't like and doesn't use his filter anymore.

Posted by Osi Osgood (Member # 424) on August 28, 2007, 11:35 AM:

This is a very interesting subject!

A short time ago, I found two 3D glasses, but they were a curious variety, instead of red blue, they were purple green. It's a very light green. Now, I had seen those filters on the internet that you were talking about, and I decided to try putting one of the light green in front of a pinkish film I was projecting. A little change, but not much. then I thought,

"Hey, why not sandwich two of those light greens together?"

... which i did, and I was amazed at the results!!

(I really need to see how to do screen shots here, as this would really help illustrate this)

Now, night scenes it didn't help as much, of course, as the blacks were a brown colour, but the daylight scenes were enormously better. Not as good as the original colour, of course, but very watchable and fortunately, due to the very light green, not much light was lost at all. There was a slight softening of the image, but not too bad. Very nice
skin tones. Also, due to the light green, it barely showed up on the screen in the whites, (essential, as the film in question "Gorky park" takes place in the snowy winter.)

Very interesting topic, to be sure.

Posted by Winbert Hutahaean (Member # 58) on August 29, 2007, 03:44 AM:

Osi,

I reallly want to see the screen shot. Would you do that for us please.

thanks,

Posted by Jeff Taylor (Member # 442) on August 29, 2007, 09:35 AM:

Sorry to say, but color filters are like the proverbial cure for VS--there just ain't none! Filters can neutralize some of the red, but they can't really put back the blues and greens. What you get is an overall blue haze to the picture, and if it's really a red print you'll loose sharpness of focus and brightness by the time you load down the image with so much blue. Xenon projection helps a little with its high color temperature, but after experimenting with everything out there I've given up.

Posted by Kevin Faulkner (Member # 6) on August 29, 2007, 11:01 AM:

I have to agree with Jeff on this one. Once the colour has gone...it's gone for good....infinitum.

After that its down to adding filters to make the red hue more acceptable. Adding filters will affect the whites, will reduce the light getting through to the screen and yes it will in some cases reduce the sharpness. Also most of these filters are blue/cyan in colour. Adding enough of this to the red hue will give you purplish colours overall and cold, dirty looking whites.
Filters do however help with films where the colour is just starting to go and where you still have greens and blues present. The addition of these filters does help to boost those colours. If the prints are all red then I would give up and watch them red.

Kev.

Personally..I've been there...done that and now don't bother any more.

Posted by Pablo Alvarez Roth (Member # 655) on August 29, 2007, 12:55 PM:

Well finnaly I bought the filters on ebay to give them a try.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=200136795697&ssPageName=STRK:MEWN:IT&ih=010

It had a very interesting result, on some prints that were awfully red these did improve greatly the color balance, on others it gave em blueish tint, I see If I can post a few pics later on but on the other side I was a bit dissapointed on the material since these filters were not rigid plastic or glass but more celofane type and doubt the material cost 10 us dollars, but the result was interesting.

worth the try.

cheers
pablo.

Posted by Douglas Meltzer (Member # 28) on August 29, 2007, 02:19 PM:

I've tried various types of filters over the years, and have found that a light plus green (1/4-1/2) worked the best on fading prints, but like Kevin, I prefer having the sharpness and the full amount of light over a very slight color correction. After a bit, the eye adjusts anyway and that last reel somehow doesn't seem as bad as the first.

Doug

Posted by Jean-Marc Toussaint (Member # 270) on August 29, 2007, 02:33 PM:

Doug, I use a 1/4 blue (is it colored gel #203? can't remember the code, it was given to me by a DP friend) when the print is very red. But Jeff, Kev and you are right, sharpness and light throughput are more important.

Posted by Winbert Hutahaean (Member # 58) on August 31, 2007, 03:50 AM:

Hi all,

Some screen shots can be seen here.

I my self prefer to have afilter that can change the reddish print to become Black and White.

Anyone knows it?

thanks,

Posted by Kevin Faulkner (Member # 6) on August 31, 2007, 04:02 AM:

It depends on which you prefer.....red prints or blue prints!

You wont be able to get any filters to give you a black and white image. Because you are adding filters to the existing image/light the whites will also turn that colour as can be seen in some of those screen shots by the seller. The 3 last comparisons show that up very well indeed.
Whats needed is a filter system which is graduated so the darker areas are corrected more than the lighter areas and this is just not possible with filters over an existing lens etc.

Kev.

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