Archived posting to the Leica Users Group, 2006/01/16

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] re: digital treadmill
From: abridge at (Adam Bridge)
Date: Mon Jan 16 13:51:07 2006
References: <DC4B73A4105FCE4FAE0CEF799BF84B366BA9BC@case-email> <> <> <>

I've not had hands-on with anything like Nuke - although I get your
point about workflow.

Looks like Nuke is aimed at movies though because they won't even tell
you what it costs.


On 1/16/06, feli <> wrote:
> On Jan 16, 2006, at 11:38 AM, Adam Bridge wrote:
> >
> > Ummm...could you give an example of the standards you're discussing to
> > which you are comparing Photoshop with regard to color correction and
> > masking?
> >
> > Adam
> Photoshop uses a layered, linear approach to assembling it's composites.
> Modern compositing systems use a flow chart approach. You still are
> stacking layers on top of each other in a linear fashion, but you can
> branch
> off the results of one operation/layer and feed it in to another
> layer etc., and
> recombine it etc. A flowchart approach allows a very unrestricted
> workflow.
> Trust me, once you experience it you will never want to go back to
> doing things
> in a linear system.
> Here is an example of a basic color correction tool:
> In PS most of the color correction tools like the brightness/
> contrast, histogram
> operator pretty much only allow you to adjust the black point, white
> point and
> gamma of an image. Any of these operations affect all three channels
> (RGB)
> simultaneously.
> In a modern system like Nuke, the color correction node is very
> similar to
> an equalizer in an audio system, where the total range of the image
> is divided
> in to distinct bands of control.
> Initially the image is divided in to three ranges; shadows, midtones,
> highlights.
> Each range is subdivided in to offset, gamma, gain (blackpoint,
> gamma, highlights), contrast and saturation.
> In addition, you can also adjust the RGB channels separately at every
> level of this division.
> Then there is something called a Grade operator, which basically
> emulates the printing
> controls in a traditional lab and was designed to effectively deal
> with high dynamic range images,
> like a RAW file or Cineon format film scan.
> There is an operator called Stops, which lets you manipulate an image
> in terms of traditional
> film operations. You can literally print an image up or down in
> photographic stops, or printer points etc,
> just like you would in the lab.
> There also is a very powerful HueCorrector. The PS equivalent would
> be the Selective Color operator.
> In the Nuke operator you see a horizontally oriented representation
> of the hue spread. The hue spread
> is overlaid with horizontal spline curves which represent red, green,
> blue, luminance, saturation, red-suppression,
> green-suppression, blue-suppression.
> Here's how it works. Lets say you have a still life of a bowl of
> fruit containing bananas and green apples.
> In this case lets say the bananas aren't ripe, yet, so they are a
> little green.  In NUKE, you would take the
> eyedropper tool and sample the banana color in the scan. The location
> of their color value, would be indicated
> on the hue spread of the HueCorrector. Now to make the bananas appear
> ripe and yellow, you would
> select the green adjustment spline and add a point at the location
> where the eye-dropper had indicated it.
> You would then pull this point down, subtracting a little green from
> the image in only that band of the
> color spectrum, this turning the bananas yellow.
> Imagine shooting indoors, in a room that contains daylight, tungsten
> and florescent light sources.
> Now, if you are shooting film, you can't filter for all different
> temperatures at the same time.
> So the florescent light would add a green spill, and the tungsten
> lights would be very warm. Using the
> HueCorrector you would be able to neutralize and balance all three of
> these lightsources, something,
> which would be very difficult or impossible to do with something like
> the Selective Color operator.
> There are more tools, but this is a small selection.
> feli
> ________________________________________________________
>                 2 + 2 = 4
> _______________________________________________
> Leica Users Group.
> See for more information

In reply to: Message from drodgers at (David Rodgers) ([Leica] re: digital treadmill)
Message from abridge at (Adam Bridge) ([Leica] re: digital treadmill)