[Tig] Sprit 'Film Type' Setting

Kevin Wheatley kevin.j.wheatley at gmail.com
Wed Jul 13 11:35:25 BST 2016


On Wed, Jul 13, 2016 at 9:09 AM, Steve Roberts via Tig <tig at colorist.org> wrote:
> Print - pos/neg
> Intermediate - pos/neg
> Primetime - pos/neg
> Colour - pos/neg
>
> For a projectable print in either colour or monochrome Print - Pos would be used. Is there any circumstance in which you would select Colour - Pos? (the filterwheel would have a blue filter selected at this point to counteract the orange dye mask in neg). What's the difference between a colour neg and an intermediate neg that requires a different filter in the colour wheel? Both are dye-masked, aren't they? Maybe by different amounts?
>
> Do some of these combinations simply not make sense for any film stock, so you would never select them in the real world?

The filter wheel is used to 'bias' the spectral distribution of the
light to better match the sensor sensitivities after passing through
the film base. If you look at the colour of a blank frame of the
different film types you will see that they are different colours, neg
looks more orange than interpos, print is mostly clear (to the eye),
etc. So you select the best filter position to get the best signal to
the CCD.

The negative/positive selection just inverts the interpretation of the
signal, most obvious case this is needed for is with intermediate
elements used during bulk printing, the first IN made from an original
camera neg (-ve image) will be made into a positive image on the IN
base, the second IN made from that will be negative image on IN base,
the print will then be positive image on a print base.

So you can have an intermediate element on intermediate base stock but
with either image state.

It is possible to have this occur on camera negative too if somebody
has a film recorder that can expose onto camera negative, it is
unlikely to occur with print or primetime.

Kevin



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