8mm Forum: Colour Correction

This is topic Colour Correction in forum 8mm Forum at 8mm Forum.

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Posted by Stewart John Boyle (Member # 1785) on January 28, 2010, 12:02 PM:

Hi All,
A random question for all the members follows,
Has anyone ever tried to colour correct a red print by placing coloured filters in front of the lens? Eg blue or green?
Linear thinking i know.. but what where the results?
Thanks
Stewart

Posted by John Skujins (Member # 1515) on January 28, 2010, 12:31 PM:

I haven't tried it but I would assume if the print is all red then any filter would result in a single color also. A blue filter would give you blue + red = purple. A green filter would give you green + red = brown, since green = blue + yellow.

Posted by Michael O'Regan (Member # 938) on January 28, 2010, 12:42 PM:

No, no, no...never!!
It's like wearing earmuffs so that you won't hear the scratches on your beloved old Beatles record.

Faded is faded - get a better print or buy a DVD.

[Big Grin]

Posted by Martin Jones (Member # 1163) on January 28, 2010, 12:43 PM:

Colour filters are "subtractive". A BLUE filter cannot pass RED light, so if your try to shine red light (i.e. a very red print) through a blue filter the result is BLACK.
You can only "correct" if their are traces of other colours in the print as well and the filters are also "combinations of colours"; you can never "correct" completely
Martin

Posted by Stewart John Boyle (Member # 1785) on January 28, 2010, 12:45 PM:

Thanks John,Michael,Martin [Smile]

Question answered,almost immediatley !!
Best Wishes
Stewart

Posted by Winbert Hutahaean (Member # 58) on January 28, 2010, 12:53 PM:

There is a specific topic regarding this and Doug has tried once.

I would try to locate it. But definitely Doug reported that filter worked well for some films.

cheers,

Posted by Stewart John Boyle (Member # 1785) on January 28, 2010, 12:57 PM:

Good Morning Canada [Smile]

Thanks Winbert, it would be very interesting reading.
Doug, if you can post your results quicker i would be very thankfull.
Stewart

Posted by Winbert Hutahaean (Member # 58) on January 28, 2010, 01:00 PM:

Hi Stewart. Is afternoon over here [Wink]

.

Here is the link

Doug is suggesting Wittner which is of course expensive. Anyone can suggest a hand-made cheapo ones? [Big Grin]

cheers,

Posted by Stewart John Boyle (Member # 1785) on January 28, 2010, 01:03 PM:

[Smile]

Winbert
Reading it now my friend
Stewart

Posted by Osi Osgood (Member # 424) on January 28, 2010, 01:17 PM:

I mentioned this a little whiloe back.

I had went the way of a light blue/cyan filter, and while it does help the color (on a reddish print that still has some decent color, mind you), it cuts down on the available light.

Then I thought of an experiment.

I went to our local art store, (40 miles away, I happened to be ther for something else) and I bought a large light cyan blue poster board, going on the theory that you could get thye same color correction for the print with less loss of brightness. It worked quite well.

Admittedly, colored poster board is hard to come by and a little expensive. Note, I'm talking of the thick foam poster board that also has the shiny surface, which also cuts down on the light loss, being quite reflective of light.

Posted by Martin Jones (Member # 1163) on January 28, 2010, 01:24 PM:

Projecting onto a "coloured" board is "additive" and will add the colours of the board to the light reaching it, but only if some additional white light falls on the board to "generate" the board colour.

Martin

Posted by Stewart John Boyle (Member # 1785) on January 28, 2010, 01:34 PM:

I think the problem of Colour degridation will probably never be fixed completely, but perhaps with a number of trial and error experiments,some acceptable results could be produced.
Yours to ponder over
Stewart

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